Feedback-induced dissipation and noise suppression in medium-scale systems

Abstract

A high-gain and low-noise negative feedback control ("feedback control") system can detect charge transfer in a quantum system at room temperature. The feedback control system can reduce the dissipative coupling between the quantum system and its thermodynamic environment. The feedback control system can be integrated with a standard commercial voltage-impedance measurement system, such as a potentiostat. On the one hand, the feedback control system includes: a plurality of electrodes configured to be electrically coupled to a sample, and a feedback mechanism coupled to a first electrode of the plurality of electrodes. The feedback mechanism is configured to detect a potential associated with the sample through the first electrode. The feedback mechanism provides a feedback signal to the sample through a second electrode of the plurality of electrodes, and the feedback signal is configured to provide excitation control of the sample at a third electrode of the plurality of electrodes.

Description

[0001] Related Applications

[0002] This application claims the benefit of priority under 35 USC §119(e) to U.S. Provisional Patent Application No. 62 / 328,798, filed on April 28, 2016, the entire contents of which are expressly incorporated herein by reference.

[0003] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0004] This invention was made with Government support under Contract N66001-11-1-4111 awarded by the Defense Advanced Research Projects Agency. The U.S. Government has certain rights in this invention. Technical Field

[0005] The subject matter described herein relates to the detection of analytes. Background of the Invention

[0007] Potentiostats are commonly used in electrochemical experiments to detect the properties of physical systems, for example, the electrochemical interface between a solid phase and a liquid phase. The potentiostat uses a three-electrode system, including a reference electrode, a working electrode, and a counter electrode. The potentiostat can be operated by maintaining a fixed potential difference between the working electrode and the reference electrode and measuring the current flowing through the analyte and flowing through the electrode-analyte interface via the counter electrode. For example, in most electrolysis experiments, a potentiostat can be used to measure the total charge transferred across the electrochemical interface under a fixed potential difference. The measured charge can indicate a reduction / oxidation reaction at the interface.

[0008] The physical system (e.g., electrode-electrolyte interface) detected by the potentiostat can include systems that exhibit quantum properties such as transport properties associated with mesoscale phenomena. However, the coupling of the quantum system to its environment (e.g., the surrounding thermodynamic bath) at room temperature can cause classical behavior in the quantum system. Due to the coupling with the electronic system, the dissipative forces acting on the quantum system, etc., external noise (e.g., voltage noise) is introduced into the quantum system, so the conventional potentiostat is limited in its ability to detect quantum properties at room temperature in the electrochemical system. Therefore, the conventional potentiostat cannot detect quantum phenomena and mesoscale phenomena (phenomena located between the behavior of classical mechanics and quantum mechanics). The detection of mesoscale properties can be very important for novel sensing, timing and communication paradigms. Therefore, it is desirable to develop a potentiostat that can detect and quantify mesoscale phenomena. SUMMARY OF THE INVENTION

[0010] The present application provides a high-gain and low-noise negative feedback control system that allows the detection of quantum mechanical properties of analytes at room temperature. In a medium-scale system including the analyte, this can be accomplished by reducing dissipation and suppressing noise during the charge transfer process.

[0011] Accordingly, in one aspect, the present invention provides a system comprising at least: (a) a plurality of electrodes configured to be electrically coupled to a sample; and

[0012] (b) a feedback mechanism coupled to a first electrode of the plurality of electrodes and configured to detect a potential associated with the sample through the first electrode, wherein the feedback mechanism provides a feedback signal to the sample through a second electrode of the plurality of electrodes, and the feedback signal is configured to provide excitation control of the sample at a third electrode of the plurality of electrodes. On the other hand, the sample is a charge transfer system at a molecular level. On the other hand, during the process of electron excitation transfer (EET) in the charge transfer system at the molecular level, the feedback signal provides excitation control of the charge transfer system at the molecular level. In any aspect of the above and aspects herein, the excitation control weakens the dissipation of the charge transfer system at the molecular level from the surrounding thermodynamic pool. In any aspect of the above and aspects herein, the excitation control can reduce the dissipative coupling of one or more electronic vibration energy levels in the charge transfer system at the molecular level with the external pool. In any aspect of the above and aspects herein, the first, second and third electrodes are the reference electrode, counter electrode and working electrode of the potentiostat, respectively. In any aspect of the above and aspects herein, the feedback mechanism may include: a first negative feedback amplifier configured to generate a first signal based on the difference between the detected potential and the set potential value. In any aspect of the above and aspects herein, the feedback mechanism may include: a second negative feedback amplifier configured to receive the first signal and generate the feedback signal. In any aspect of the above and aspects herein, the system may include: a current detection system configured to detect the current associated with the second electrode. In any aspect of the above and aspects herein, the detected current indicates an analyte in the charge transfer system at the molecular level.

[0013] On the one hand, the present invention provides an analyte detection method including at least the following: (a) detecting an electric potential associated with a sample by a first electrode in a plurality of electrodes by a feedback mechanism. The plurality of electrodes may be electrically coupled to the sample; (b) generating a feedback signal by the feedback mechanism; and (c) providing the feedback signal to the sample by a second electrode in the plurality of electrodes. The feedback signal may be configured to provide an excitation control of the sample at a third electrode in the plurality of electrodes. On the other hand, the sample is a charge transfer system at a molecular level. On the other hand, during an electron excitation transfer (EET) in the charge transfer system at the molecular level, the feedback signal provides an excitation control of the charge transfer system at the molecular level. In any aspect of the above and herein, the excitation control weakens the dissipation of the charge transfer system at the molecular level from the surrounding thermodynamic pool. In any aspect of the above and herein, the excitation control weakens the dissipation of the charge transfer system at the molecular level from the surrounding thermodynamic pool. In any aspect of the above and herein, the excitation control may reduce the dissipative coupling of one or more electronic vibrational energy levels in the charge transfer system at the molecular level with an external pool. In any aspect of the above and aspects herein, the first, second and third electrodes are respectively the reference electrode, counter electrode and working electrode of the potentiostat. In any aspect of the above and aspects herein, the feedback mechanism may include: a first negative feedback amplifier configured to generate a first signal based on the difference between the detected potential and the set potential value. In any aspect of the above and aspects herein, the feedback mechanism may include: a second negative feedback amplifier configured to receive the first signal and generate the feedback signal. In any aspect of the above and aspects herein, the system may include: a current detection system configured to detect the current associated with the second electrode. In any aspect of the above and aspects herein, the detected current indicates the analyte in the charge transfer system of the molecular scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 An implementation of a feedback system for a process is presented;

[0016] Figure 2 An implementation of a potentiostat with a high gain and low noise feedback control system is presented;

[0017] Figure 3 Demonstrates the effect of a high-gain and low-noise feedback circuit on the power spectral density (PSD) of voltage noise;

[0018] Figure 4A A circuit model of an oscillator in contact with a thermodynamic cell is shown;

[0019] Figure 4B Demonstrates the use of applying a signal to Figure 4AThe three-terminal feedback system of the oscillating system shown in;

[0020] Figure 5 Shows the effect of feedback and no feedback on Figure 4B Simulation diagram of the oscillation amplitude measured at C1 in response to a small signal AC excitation;

[0021] Fig. 6A Demonstrated that without feedback Figure 4A The oscillator node V x The voltage noise spectral density is given by X r Simulation of the function of ;

[0022] Figure 6B Demonstrated that in the presence of feedback Figure 4B The oscillator node V x The voltage noise spectral density is given by X r Simulation of the function of ;

[0023] Figure 6C Demonstrated that in the presence of feedback Figure 4B The oscillator node V x The voltage noise spectral density is given by X m Simulation of the function of ;

[0024] Fig. 7A A circuit model of a two-state electron excitation transfer (EET) system coupled to an external cell in a reservoir mode is presented according to various example embodiments described herein; and

[0025] Figure 7B Shown with Fig. 7A The EET system shown in FIG. 1 is coupled to a feedback system for attenuating environmentally induced dissipation. DETAILED DESCRIPTION OF THE INVENTION

[0027] A high-gain and low-noise negative feedback control (hereinafter referred to as "feedback control") system can detect the quantum mechanical properties of charge transfer occurring in a quantum system at room temperature. The feedback control system can weaken the dissipative coupling between the quantum system (e.g., electron vibration energy levels) and its thermodynamic environment by suppressing the internal energy fluctuations associated with the quantum system (e.g., fluctuations in the electric field). Dissipative coupling that is significant at room temperature can hinder the detection of quantum phenomena (e.g., transport properties associated with mesoscale phenomena). A measurement architecture with a low-noise feedback control system can detect quantum phenomena at room temperature that may not be observable using traditional measurement equipment and techniques.

[0028] The feedback control system can be integrated with a standard commercial voltage-impedance measurement system, such as a potentiostat. The standard potentiostat has a three-electrode circuit topology, and can measure the electrical characteristics of an electrochemical system. The electrochemical system can include an electrode (e.g., metallic or semiconductor), an electrolyte (e.g., aqueous solvent, organic solvent, etc.), a buffer salt, a test sample (e.g., a composite matrix) component, one or more analyte species, can serve as a charge source or a sink (sink) to carry out a redox species of charge exchange with an electrode, etc. Redox species can include, for example, ferrous cyanide / iron pairs, ferrocenium ions, and ruthenium hexaamine complexes. Analytes can include, for example, overall microorganisms or their components, including DNA, RNA oligomers, peptide fragments, proteins, polysaccharides, polysaccharides, metabolites, etc. The three-electrode circuit topology includes a counter electrode, a working electrode, and a reference electrode that can be electrically coupled to an electrochemical system.

[0029] The feedback control system can be integrated with a potentiostat, and the potential and / or current at one or more of the three electrodes can be controlled. The feedback control system can be configured to control the potential of the electrochemical system (e.g., by setting it to a desired value) and / or suppress the voltage noise in the electrochemical system. The feedback control system can detect the potential of the electrochemical system (e.g., at a reference electrode) and send a corrective feedback signal (e.g., a current signal, a voltage signal) to change the potential and / or reduce the voltage noise associated with the electrochemical system. The corrective feedback signal can also change the electron exchange process at the working electrode. The feedback control system can include one or more high-gain amplifiers, which can be cascaded together in some embodiments. The feedback system can also include a voltage buffer, which allows the potential to be detected with minimal impact on the electrochemical system. For example, from the perspective of the electrochemical system, the impedance of the voltage buffer can be very high. This can prevent the current from the electrochemical system from flowing into the voltage buffer. Therefore, the potential of the electrochemical system can be detected with minimal disturbance to the electrochemical system.

[0030] The suppression of the voltage noise of the electrochemical system can lead to the suppression of the energy fluctuations of the quantum electrochemical system (e.g., near the interface between the electrolyte and the working electrode). This can lead to, for example, efficient resonant charge transfer between the redox species dissolved by the electrolyte and the working electrode (e.g., charge transfer between discrete electronic energy levels of vibration-dressed electronic states in the redox species of the molecular charge transfer system and the energy levels of the working electrode). The feedback control system can limit various scattering contributions from the thermodynamic cell mode, which may lead to resonant charge transfer.

[0031] The effect of the analyte on the charge transfer process between the redox species and the working electrode can be detected due to the suppression of voltage noise and the resulting electric field fluctuations at the electrode-electrolyte interface (e.g., the interface between the electrochemical system and the working electrode). For example, the charge transfer process may be modified by the vibrational structure of the analyte, which can be seen from the perturbing effect of the introduction of the analyte on the electrode-electrolyte interface. The analyte can be detected by comparing the modified charge transfer process of the analyte with a database containing information related to the effect of each analyte on the charge transfer process.

[0032] The use of a low-noise potentiostatic feedback control system to detect analytes based on their interaction with a charge transfer process provides several advantages. For example, some embodiments allow label-free and probe-free chemical / biological detection using information about the vibrational structure of the analyte target. For example, analyte detection using vibrational mode information does not require ultra-low temperatures (less than 20 Kelvin) and high vacuum (e.g., less than 10 -5 The analyte can be detected under ambient conditions. In an embodiment, the detection can be performed with high sensitivity (e.g., less than 1 pg / ml detection limit) and high specificity (e.g., close to 100%) over a large dynamic range (e.g., 1 pg / ml-1 ug / ml). This concept can be extended to other types of systems, such as interfaces between combinations of solid-state metals, semiconductors, and insulators.

[0033] In one aspect or embodiment, Figure 1 A standard feedback system 100 is shown in which the output of a process 102 is used to determine the input to the process in order to maintain the desired operation of the process 102. Figure 1 1 , the output 116 of the process 102 is used to determine a feedback signal 118 via the feedback system 104. The feedback signal 118 may be used together with the input signal 112 to determine a process input 114 for the process 102. Determining the process input 114 may involve, for example, calculating the difference between the input signal 112 and the feedback signal 118 and amplifying the difference via the gain stage 108.

[0034] Figure 2An embodiment of a potentiostatic device 200 having a feedback control system coupled to an electrochemical system is shown. The electrochemical system 250 may include a molecular-scale charge transfer system (e.g., electrolyte 212 and electrode 204), and an analyte (not shown) contained in the electrolyte phase of the system. The potentiostatic device 200 and the electrochemical system 250 may be electrically coupled via one or more of the counter electrode 202, the working electrode 204, and the reference electrode 206. The potentiostatic device 200 may apply a potential bias across the electrochemical system 250 (e.g., between the reference electrode 206 and the working electrode 204). The applied bias may cause charge transfer between the redox active species in the electrolyte 212 and the nanoscale working electrode 204. The exchange of electrons between the electrode and the redox species may cause energy exchange, and is therefore referred to as electron energy transfer (EET). The transport of redox species in the electrochemical system 250 may supplement the electron flow in the potentiostatic device 200 and complete the charge flow circuit.

[0035] For example, when the counter electrode is much larger in area than the working electrode and the current entering the reference electrode 206 is small (e.g., zero), the current flowing into (or out of) the counter electrode 202 can be related to the electron exchange between the redox species and the working electrode 204. Therefore, measuring the current flowing into (or out of) the counter electrode can indicate the rate and nature of the electron exchange at the working electrode 204 (or the counter electrode 202). The impedance (e.g., X) of the electrical coupling to the counter electrode 202 can be measured. m ) to detect the current. The voltage difference can be measured, for example, by using a low noise voltmeter or a transimpedance amplifier chain. In some embodiments, by measuring the current at the working electrode 204 (e.g., by measuring the voltage difference across an impedance electrically coupled to the working electrode 204), the electron exchange rate at the working electrode 204 can be detected.

[0036] Electrons in redox species can occupy vibrationally modified electronic energy states (also referred to as electronic vibration states). The electronic exchange between the electronic vibration states of the redox species and the energy states in the electrode can be affected by the environment or thermodynamic pool (e.g., the dielectric environment of the solvent). The electron exchange process is also affected by the presence of the analyte (e.g., the analyte present on or near the surface of the working electrode) and the background matrix of the sample being tested. The interaction between the polarization mode of the analyte (e.g., the slow-moving vibration mode of the analyte species) and the electronic vibration state of the redox species can disturb the electron exchange process, or the interaction with the available electronic mode of the analyte can even directly participate in the electron exchange process between the redox species and the working electrode. The effect of the analyte on the electron exchange process can be detected by measuring the charge exchange current at the working electrode (204)-electrolyte (212) interface, which can be measured at the counter electrode 202 (or working electrode 204) as described above. By measuring the charge exchange current at the working electrode (204)-electrolyte (212) interface, the charge exchange current ... at the working electrode 202 (or working electrode 204) can be measured at the working electrode 204) as described above. By measuring the charge exchange current at the working electrode ( 设定 By measuring the current, a current vs. voltage (IV) trace (which may include the effects of the analytes) can be generated for the electrochemical interface 250. By quantifying the perturbations introduced by these analytes to the measured charge transfer flux at the interface, the analytes in the electrochemical system 250 can be fingerprinted (e.g., their determined IV traces).

[0037] Thermal interference with the electric field energy near the working electrode 204 affects the electron exchange process at the working electrode 204. Thermal interference affects the electron exchange process between the redox species and the electrode, and thus hinders the determination of the analyte in the electrochemical system. For example, fluctuations in the electric field can be proportionally related to the dissipative force acting on the electron exchange process, which can obscure any resonant interactions present in the electrochemical system. Thermal interference in the electric field may be caused by the inherent electrostatic environment at the electrochemical interface or by electronic noise injected from the bias and current measurement circuit system coupled to the electrochemical system (e.g., from the reference electrode 206, the counter electrode 202, etc.). Thermal interference can increase or decrease with the temperature of the system, making it difficult to detect analytes under ambient conditions (e.g., above 50 Kelvin).

[0038] The feedback control system in the potentiostatic device 200 can mitigate the effects of thermal interference and dissipation, and thus allow analyte detection at room temperature during electron exchange, for example, through resonant properties. The feedback control system can use negative feedback to apply a desired bias across the electrochemical interface between the electrolyte 212 and the working electrode 204, and can suppress intrinsic and extrinsic sources of thermal interference.

[0039] like Figure 2As shown in FIG. 1 , the feedback control system includes a pair of ultra-low noise amplifiers 210 and 220 electrically coupled to an electrochemical system 250 via a counter electrode 202 and a reference electrode 206. The feedback control system detects the potential V of the redox active species in the electrolyte 212 at the reference electrode 206. 参考 . V 参考 may represent the electronic vibration energy of the redox species in the charge transfer system 212 .

[0040] In some embodiments, the feedback control system may include a low noise voltage buffer 260 that can detect the potential V with minimal disturbance to the charge transfer system 212. 参考 This can be achieved, for example, by designing the voltage buffer 260 to have a high impedance from the perspective of the charge transfer system 212. Figure 2 As shown in FIG. 1 , the voltage buffer includes cascaded field effect transistors 262 and 264 (eg, pMOS transistor, nMOS transistor). The transistor 262 (eg, nMOS transistor) may have a potential +V at its drain. B The voltage source is electrically connected to the reference electrode 206 at its gate (via the reference electrode impedance X 参考 ) is electrically connected. The drain of transistor 264 (eg, nMOS transistor) can be electrically connected to the resistor R B1 The source of transistor 264 can be electrically connected to the source of transistor 262. B2 With potential -V B In addition, the gate of transistor 264 may also be electrically connected to a voltage source having a potential of -V B The voltage buffer 260 can generate a voltage signal V 测量 (at the drain of transistor 264), which voltage signal represents the voltage V detected by voltage buffer 260 at reference electrode 206. 参考 .

[0041] A pair of cascaded amplifiers 210 and 220 are configured to deliver a high-gain, low-noise correction signal to the electrochemical system 250 via the counter electrode 202. The correction signal is related to the potential V 设定 (related to the desired potential of the electrochemical system 250) and the detected potential V 测量 Amplifier 210 has a gain of A1 and has two inputs: V 设定 (at the inverting input) and V 测量 (at the non-inverting input terminal). The output terminal of the amplifier 210 is connected to the input terminal of the amplifier 210 through the resistor R F1 The output of the amplifier 210 can also be connected to the inverting input terminal through the resistor R S2The output terminal of the amplifier 220 can be connected to the inverting input terminal of the second amplifier 220. The non-inverting input terminal of the amplifier 220 can be connected to the ground potential. The output terminal of the amplifier 220 can be connected to the ground potential through the resistor R F2 The arrangement of connecting the output of the amplifiers (e.g., 210 and 220) to their inverting inputs is called negative feedback. The cascaded negative feedback amplifiers (cascaded amplifiers 210 and 220) can be used to generate a negative feedback signal for an input signal (e.g., V 设定 With V 测量 The difference between the output voltage and the output voltage of the amplifier 210 can provide high gain and improve the signal-to-noise ratio of the output signal. 设定 and the measured voltage V 测量 The output of the amplifier 220 may be proportional to the difference between the input at the inverting input terminal (eg, the output of the amplifier 210 ) and the input at the non-inverting input terminal (eg, a ground potential value).

[0042] The cascaded amplifiers can control the potential of the electrode 202 and / or the current flowing into (or out of) the electrode. The output of the amplifier 220 (corrective feedback signal) can be connected to the electrode 202 through the impedance X M The corrective feedback signal can, for example, set the potential of the counter electrode 202 to a desired potential (e.g., with respect to V 设定 ), injecting a correction current into the electrochemical system 250, etc. By measuring the impedance X M The potential V at both ends TIA (e.g., by a voltmeter) and using the measured potential V TIA Divide by the impedance X M , the corrective current signal flowing into (or out of) the electrode can be detected. As described above, by 设定 By measuring the corrected current flowing into (or out of) the counter electrode, a current vs voltage (IV) plot can be generated. This IV trace can contain the "fingerprint" of the analyte in the electrochemical system, and the identity of the analyte can be detected by comparing the detected IV data with the IV data of other analytes.

[0043] By electrically connecting the electrochemical system (analyte and electrolyte) to the potentiostatic device 200 via the counter electrode 202, the reference electrode 206, and the working electrode 204, the analyte (or multiple analytes) in the electrolyte can be detected. The user can set the voltage at the inverting input of the first amplifier 210 (for example, by using a low-noise tunable voltage source). The voltage buffer 260 can detect the voltage at the reference electrode without increasing the inherent noise and can send a signal with a voltage value (related to the detected voltage) to the non-inverting input 210 of the first amplifier. Based on these two inputs, the cascaded high-gain low-noise negative feedback amplifier (e.g., 210 and 220) sends a corrective feedback signal (e.g., a current signal) to the electrochemical system via the counter electrode. The feedback detection system (e.g., a voltmeter, an ammeter, etc.) in the potentiostatic device 200 can detect the feedback signal. The feedback detection system can communicate with a control system (e.g., a computing device), which can record information related to the detected feedback. The control system can also control the set voltage V 设定 For example, the control system can sweep the set voltage V 设定 The control system can generate a data set of multiple set voltage values ​​and corresponding feedback signals (e.g., current). The control system can compare the generated data set with feedback response data sets for other electrochemical systems (with different electrolytes, analytes, etc.) and determine the identity of the analyte in the electrochemical system at hand.

[0044] Figure 3 The effect of a high-gain and low-noise negative feedback circuit on the power spectral density (PSD) of voltage noise at the reference node of a constant potential device 200 is shown. PSD indicates noise at various frequencies. Curves 302 and 304 represent the PSD of the voltage noise detected at the reference electrode of the constant potential device in the absence of low-noise feedback control and with low-noise feedback control, respectively. A constant potential device (e.g., constant potential device 200) with low-noise feedback reduces the PSD at the reference electrode by several orders of magnitude. Reduced fluctuations cause less thermal interference from the fluctuating electric field to the electronic vibration state of the redox active species in the electrolyte. In addition, in contrast to existing constant potential devices, the high gain of the low-noise feedback control system of the constant potential device 200 can weaken any dissipation from the thermodynamic pool acting on the electron transfer process at the electrochemical interface.

[0045] Can be used Figure 4A , Figure 4B , Fig. 7A and Figure 7BThe circuit elements described in (e.g., inductors, capacitors, resistors, etc.) simulate the coupling between the energy levels involved in the electron transfer process (e.g., electronic vibration states of redox species, energy levels of metal electrodes, etc.) and the thermodynamic environment and between themselves. For example, a resistor (e.g., Figure 4A and Figure 4B X in r , Fig. 7A and Figure 7B R 1 and R 2 ) represents dissipative coupling to the external environment and / or adds noise (e.g., voltage noise) to the energy levels related to thermal fluctuations, which is itself represented by reactance (capacitance and inductance). Circuit elements (e.g., resistors, inductors, and capacitors) specify the electrostatic relaxation of the electrochemical interface in response to a time-varying voltage bias, which is generally separable from the much faster dynamics of the nuclear and electronic modes of the system. It can be argued that for high-gain and low-noise negative feedback control systems, the dissipative coupling of the participant energy states (e.g., electronic vibrational modes of redox species) to the environment is reduced when the time scale of the feedback response is comparable to the relaxation time scale of the electrochemical interface. For example, as demonstrated in Eqs. 7.1a and 7.1b, for high gain (e.g., A 1 A 2 ), with a damped kernel γ 11 The terms in the denominators of Equations 7.1a and 7.1b approach zero. This indicates that, for high gains, the damping of the electron transfer process is reduced.

[0046] For the case of quantum systems coupled to a large number of modes, preserving the superposition of quantum probability amplitudes requires reducing the interaction between the system and the pool, or reducing the number of pool modes that can interact with the system. Schemes for preserving interference between states will enable new room temperature systems to exhibit quantum behaviors that can be applied to sensing, computing, and energy conversion. For example, it is believed that persistent quantum coherent interference of exciton waves promotes the efficiency of the EET process and, by extension, the efficiency of photosynthetic processes mediated by EET transport.

[0047] In the context of the above summary, the embodiments described herein are intended to excite control of medium-scale charge transfer systems with the aid of classical electronic negative feedback loops. The embodiments can extend the resonant interaction between electronic modes and vibrational modes in electrochemical systems. An environmentally coupled molecular system composed of single-stage donor and acceptor species, "dressed" by a pool vibrational mode set, is used to simulate the charge transfer process. This produces an equivalent circuit model in which the kinetic variables describe the wave function probability amplitude. The effect of feedback on the wave function probability amplitude can then be described with respect to the kinetic variables of the circuit model.

[0048] "Medium" scale properties are typically observed in devices at ultra-low temperatures and in high vacuum type environments, and these unique properties can enable novel applications in many industries, including timing references, memory, communications, and sensing. However, these medium structures are relatively unsuitable for practical deployment because these properties only manifest for an idealized set of conditions, and achieving these idealized conditions requires huge overhead. With the feedback topology described herein, these properties can be achieved at room temperature and in "dirty" systems, making these devices a practical reality. The proposed topology can be easily scaled, thereby minimizing the space and energy overhead used to implement such systems.

[0049] The equation of motion for a one-dimensional particle (system) coupled to a cell with damped vibration modes is given below:

[0050] and (1.1)

[0051]

[0052] in, is the damping kernel, and m, k B , T, and V(x) are the system mass, Boltzmann constant, cell temperature, and conservative potential, respectively. is a zero mean and in the classical limit Gaussian function of the given correlation.

[0053] Thus, the magnitude of the thermal disturbance acting on the system is related to the dissipative forces exerted by the environment, subject to the assumption that the thermal reservoir is large enough so that the pool vibration mode continues to be in equilibrium throughout its interaction with the system. These equations of motion are derived from a Hamiltonian description of the system and the environment, where the environment is modeled as a collection of non-interacting harmonic oscillators (ho) and the interaction between the system and the environment is bilinear in the environment ho coordinates and in the system coordinates, as follows:

[0054]

[0055] Among them, except for the interaction term In addition, there are compensation items This compensation term results in a shift in the cell coordinates due to coupling with the system. In this framework, the damping kernel and thermal fluctuations are given by:

[0056]

[0057]

[0058] in, and are randomly chosen initial values ​​of the position and momentum coordinates of the vibration mode α. Under the assumption that these values ​​are sampled from an equilibrium Boltzmann distribution, the fluctuation dissipation relation can be shown to hold in, is the real part of the kernel. gives the equivalent cell temperature as seen by the system. In the Markov limit, when the environment-system interaction has no memory, The real part of the parameter η will represent the effective viscosity of the mechanical system, or can be interpreted as the linear resistance in an oscillating circuit, e.g. Figure 4B The one shown in .

[0059] Figure 4A A circuit model of an oscillator in contact with a thermodynamic cell is presented according to various exemplary embodiments described herein, wherein a classical excitation source applies a signal to the oscillator system through a dissipative contact. Before further describing the drawings, it is noted that the Figure 4A , Figure 4B , Figure 5 , Fig. 6A ,and Figure 6B The purpose is to demonstrate the concept of feedback and the reduction of dissipation and noise according to the embodiments described herein. The application of this feedback in the basic system shown in these figures is also representative and is provided to explain the concept of the present invention, which includes feedback applied to various medium-scale (and potentially other) charge transfer systems.

[0060] The system in question (whether quantum or classical) is stimulated with thermal disturbances induced by a randomized environment, and these disturbances are balanced by dissipative forces as the system moves in a field described by an electric potential. According to these embodiments, a mechanism based on electronic feedback is proposed for bandwidth-limited control of these thermal disturbances and the associated damping forces. The case of an electrical oscillator is considered here for exemplary purposes, but the proposed mechanism can also be extended to mechanical systems.

[0061] As described herein, a scheme is introduced by means of which a system is decoupled from a physical reservoir in contact with it and coupled to another pool with a pre-specified spectral density, thereby ensuring control of the effective "temperature" of the pool and the damping experienced by the system. In this context, Figure 4B A three-terminal working electrode (WE), reference electrode (RE), and counter electrode (CE) feedback system is presented to Figure 4A The same signal shown in is applied to an oscillating system, where the gain in the feedback loop reduces the dissipative coupling to the environment. Figure 4BThe feedback system shown in FIG. 13 provides feedback to the three-electrode analog measurement topology circuit 1300 shown in FIG. 13 of U.S. Patent Publication No. 2014 / 0043049, for example, which also shows a WE electrode, a RE electrode, and a CE electrode. The entire contents of U.S. Patent Publication No. 2014 / 0043049 are incorporated herein in their entirety.

[0062] like Figure 4B As shown in the example, the sequence of cascaded amplifiers A1 and A2 is configured to: When transmitting and and The measurement is made using a buffer amplifier A1 with a high impedance input, thereby minimizing leakage current in the measurement. Ideally thought of for detecting the reservoir voltage The physical reference electrode (RE) has zero source impedance and is directly proportional to the correction signal V applied to the system. x' In response to the classical voltage excitation bias applied at the reference electrode, Figure 4A and Figure 4B The circuit diagram in the figure measures the current flowing through the system across the dissipative element X. r and X m The current I x and I x’ .

[0063] against Figure 4A and Figure 4B The corresponding transimpedance response of the system in is:

[0064] and (4.1)

[0065]

[0066] Among them, Y s is the resonant component of the system, represented by Y s =(1 / ωC 1 -ωL 1 ) is given. 1 ,A 2 is the gain function of the corresponding amplifier; the dissipative element X in (4.1, 4.2) r and X m has real and imaginary components obtained by averaging over all vibration modes:

[0067]

[0068] Therein, the first term comprising the main part of the integration on the complex plane (symbol PP) represents the resonant frequency shift, and the real term is the dissipation experienced by the oscillating system.

[0069] Thus, the response of an oscillatory system to thermal excitation is specified by the ensemble-averaged lumped circuit representation of the environmentally induced dissipation and by the ensemble-averaged "dressing" down of the resonant frequency of the system and also by the ambient vibration modes. In this context, Figure 5 Shows the effect of feedback and no feedback on Figure 4B 1, for example, in response to a small signal AC excitation of about 0.4V. For LTSpice IV simulation, the amplifier is selected from its component library and the following component values ​​are set: L1 = 0.198H, C1 = 142nF, X r =9878ohm, and X s = 100kohm. The selected values ​​of the components were chosen as representative examples of how feedback can attenuate dissipative interactions between an oscillating system and its thermal environment.

[0070] like Figure 5 As shown in , the application of high gain negative feedback cancels the observed dissipation and the downward modification of the resonance. The thermal disturbances induced by the reservoir on the system are measured at the RE node. These disturbances can be estimated and quoted to Figure 4A and Figure 4B The input source V in the schematic diagram 激励 , as is standard practice in noise analysis in electronic circuits.

[0071]

[0072]

[0073] The input-referred noise at the reference node is obtained by summing each voltage noise source in the feedback loop and referring it to the input:

[0074]

[0075] And Δf i is the bandwidth of the ith voltage noise source. For larger X m and A 1 , Smaller reference node bandwidth and a sufficiently quiet feedback network, the system will experience significantly less thermal disturbance, or lower equivalent pool temperature, than without feedback. The equivalent mode temperature of the oscillating system in equilibrium with the reservoir mode is estimated by the equipartition theorem to be T s =(1 / 2πCs k B )·∫ s 2 >dω, where

[0076]

[0077] Assumption |A 1 A 2 |>>1 and is independent of frequency, so ω s 2 =1 / L s C s . Integrating in the frequency domain yields:

[0078]

[0079] In effect, exchanging the physical environment surrounding the system with the cell modes associated with the measurement and feedback instrumentation allows the latter to be tailored for lower equivalent cell temperatures by selecting components with minimal thermal noise signatures. This approach to electronic "cooling" contrasts with other active feedback-based approaches in optomechanical systems that exploit large gain to enhance dissipative coupling between the mechanical system and its single-mode optical environment that has been preconditioned at cryogenic temperatures to enhance cooling efficiency.

[0080] Fig. 6A and Figure 6B Depicted in Figure 4B The oscillator node V x and Figure 4B The oscillator node V x The voltage noise spectral density of <V x 2 > / Δf and <V x' 2 > / Δf according to X r The series LC configuration representing the oscillator system creates a high Q bandpass filter due to the reduced dissipation caused by feedback. When the simulation indicates that feedback causes the system to "cool", the core with the maximum damping is cooled the most. Further, Figure 6C Showing feedback Figure 6B The oscillator node V x The voltage noise spectral density of ' is based on X m Simulation of a larger X m This results in lower total voltage noise power, resulting in lower effective cell temperature. m Increase, Figure 6C Also evident is the reduction in total integrated noise power, and equivalent system mode temperature.

[0081] ​The effect of feedback on a medium-scale charge transfer system is now described in detail, citing the simpler example of a single oscillator in contact with a thermal environment developed above. It is known that the quantum mechanics of the Hermitian Hamiltonians corresponds to the coupled motion of classical mechanical or electrical oscillators. Specifically, the classical probability amplitude describing the time-dependent state of the oscillating system is equivalent to the quantum amplitude that characterizes the evolution of the wave function of the excited quantum system by means of the time-dependent Schrödinger wave equation. Consider single-level donor and acceptor states, immersed in a reservoir pool and coupled to each other to stimulate the transition of electrons from the electron source to the sink, as follows:

[0082]

[0083] The "momentum" and "position" coordinates of the system and environment can be appropriately non-dimensionalized as follows:

[0084]

[0085] and (6.3)

[0086]

[0087] The dynamics of the system and the environment can be re-derived from the modified dimensionless Hamiltonian:

[0088]

[0089] and (6.6)

[0090]

[0091] Based on the dynamic equations of motion 6.5 to 6.7, Fig. 7A As shown in , an equivalent circuit description of the mutually coupled single-electron energy level donor and acceptor charge transfer system is proposed. Specifically, Fig. 7A A circuit model of a two-state electron energy transfer (EET) system coupled to an external pool in a reservoir mode is presented according to various example embodiments described herein. Individual energy levels are modeled as resonant elements that are dissipatively coupled to the physical environment or, in the case of feedback, to the pool reservoir in an instrumentation mode through resistors at reference nodes. Fig. 7A The reference node in defines where an external bias is applied, or in the case of feedback, where a reference probe is inserted to measure the "energy" of one of these levels constrained to the desired set point by the feedback loop. In this context, the reference is viewed as an indirect measure of a second energy level in an experimental system where direct access to the state energy is not available. Additionally, a capacitor between the resonant cell and the reference probe simulates a non-dissipative coupling between the energy levels. Fig. 7A The “ground state” of the circuit model proposed in defines the energy ground state relative to which the resonant element (ω 1 ,ω 2 ) and source excitation signal energy.

[0092] The probability amplitude Z of the donor / acceptor state 1,2 =Q 1,2 +jp 1,2 , and the probability amplitude Z of the environmental pattern α =q α +jp α Recalculate the equations of motion,

[0093] and (6.8)

[0094]

[0095] After integrating the ambient mode dynamics, it can be obtained from Estimate the state occupancy probability. Z α0 is a randomly chosen initial value for the mode occupation probability α. The form of the dynamical equations 6.8 and 6.9 constitutes a Hermitian generalization of the Hamiltonian system in equation 6.1 with linear position and momentum off-diagonal coupling, which is also known as a system with p&q coupled oscillators. By changing the variables Equations 6.8 and 6.9 are transformed by redefinition, and the first integral term on the RHS of equation 6.8 can be simplified to:

[0096]

[0097] in, and γ 11 =2πv 1 (ω 1 )g(ω 1 ) constitute the effective resonance shift and damping core, respectively. The final term on the RHS of equations 6.8 and 6.9 constitutes the noise source term for the thermally excited transfer event. Similar simplifications can be introduced for the other integral terms, resulting in equations 6.8 and 6.9 being rewritten as:

[0098] as well as

[0099]

[0100] Among them, the parameters And γ ij =2πv i (ω j )v j (ωj )g(ω j ).

[0101] For large and small interstage coupling (v 12 ) is considered as the asymptotic limit of the proposed “classical” charge transfer model. Without any loss of generality, the pooling modes of the two charge transfer component systems are assumed to be identical, i.e., for all α, v 1α =v 2α =v α , simplify the model. When , the eigenvalues ​​of equations 6.11 and 6.12 are:

[0102] and (6.13a)

[0103]

[0104] For i = 1,2Δω ii ,γ ii →0, the results in Eqs. 6.13a and 6.13b indicate that: 1 and ω 2 The amplitude of the strongly coupled ho potential well is 2v 12 The creation of new energy surfaces caused by the splitting of . The occupation probabilities of these new energy surfaces according to time are given below:

[0105] P(ω=Ω 1 ,t:Δω ii ,γ ii →0)=1 and (6.13c)

[0106] P(ω=Ω 2 ,t:Δω ii ,γ ii →0)=0, (6.13d)

[0107] For the initial condition, the equation is required to be in state ω 1 These results indicate an adiabatic transfer process characterized by the confinement of the electron charge to the adiabatic energy surface through the process of transfer from the donor to the acceptor. On the other hand, when v 12 →0, the eigenvalue is given by:

[0108] and (6.14a)

[0109]

[0110] It indicates the nonadiabatic crossing of the weakly coupled ho potential well, which is also the limit for zero dissipation. The following gives the energy surface ω of the system at the intersection of the nonadiabatic curves. 1 To the surfaceω 2 The corresponding probability of the quantum transition is:

[0111] and (6.14c)

[0112] P(ω=Ω 1 ,t:Δω ii ,γ ii →0)=1-P(ω=Ω 2 ,t:Δω ii ,γ ii →0) (6.14d)

[0113] At a small v that tends to zero 12 In the limit of and by neglecting the effects of the environment on the transition process. The transition probability as derived from equation 6.14c obeys Fermi's golden rule. The results in equations 6.13 and 6.14 confirm that the classical model is suitable for describing charge transfer in the asymptotic limit of adiabatic and non-adiabatic transfers. The effect of including the reservoir pool in the estimation of the eigenfrequency and the transition rate in the non-adiabatic case shows that the excitation caused by the coupling between the donor state and the acceptor state can be dissipated by many mechanisms for energy exchange between the charge transfer system and the external reservoir. Specifically, the interference term in equation 6.14c is now modified as:

[0114]

[0115] In addition to the damping interference between states, which is considered as the first term on the RHS, the electron moves from the energy surface Ω 1 Transition to Ω 2 The transition probability of is also determined by the indirect path through the environment in the following way: the state of a single 1 ,Ω 2 The inelastic energy exchange with the reservoir mode is determined by the density of states of the ambient mode and its coupling strength to the charge transfer system, as seen in the second term on the RHS. The third term represents the scattering into and out of the state Ω due to the environment, independent of the transfer process. 2 .

[0116] Applying an electronic feedback mechanism to attenuate the damping induced by the physical reservoir can: (a) reduce the non-dissipative coupling between the two energy states, resulting in the EET process being non-adiabatic, and / or (b) enable the preservation of coherent interference phenomena between the vibronic states of the secondary system. Simultaneous reduction of the rms voltage fluctuations between the participant energy states by a low voltage noise feedback mechanism will also help suppress the background due to the inelastic process.

[0117] In the context of electronic feedback mechanisms, Figure 7B According to various exemplary embodiments described herein, Fig. 7A The two-state EET system shown in is coupled to a feedback system for attenuating environmentally induced dissipation. According to the embodiments described herein, there is also provided Fig. 7A and Figure 7B As a representative demonstration of using feedback to reduce dissipation and noise. In embodiments, this type of feedback can be applied to various medium-scale charge transfer systems.

[0118] Here, the reference electrode or probe (RE) measures the energy of quantum state 2, and feedback sets the energy to the desired set point based on a correction signal applied to the energy of state 1. All state energies are measured relative to the system ground state as mentioned before. An ideal non-dissipative reference probe is assumed to be in contact with the participant energy state 2 so that it is subsequently adjusted at Δω. 22 ,γ 22 → 0. The analysis can be extended to the more general case with dissipation in the reference channel. In the case of applied feedback, the probability amplitudes of the states of the two participating species in the charge transfer process are given below:

[0119]

[0120] and (7.1a)

[0121]

[0122] Among these descriptors for probability amplitude, Figure 7B As shown in , the excitation signal applied to the EET system through the input of the feedback loop consists of two separable frequency components: a high-frequency part that characterizes the energy difference between the two participant states (V) of the quantum mechanical charge transfer system, and a low-frequency signal that describes the time response of the electrical feedback mechanism (ω). In the asymptotic limit of large gain, the kinetic equations governing the evolution of the probability amplitude derived from equations 7.1a and 7.1b are given below:

[0123] and

[0124]

[0125] While the probability amplitude evolves rapidly towards the steady state, the significantly slower dynamics of the time scalar ~ω are considered static. The eigenfrequencies of the charge transfer system in the limit of large gain and for the special case of a low dissipation reference probe are given below:

[0126] Ω 1 (Δω 22 ,γ 22 →0)=ω 1 and (7.3a)

[0127] Ω 2 (Δω 22 ,γ 22 →0)=ω 2 , (7.3b)

[0128] It is independent of the non-dissipative coupling between the participating species v 12 The feedback decouples the interacting energy states from each other and constrains the EET process to be essentially non-insulating. Therefore, a linear sweep of the voltage at the reference node (where ) is similar to the sweep of energy in state 2. The rms voltage noise determines the frequency ω 2 The diffusion around the cell is reduced and the low noise voltage excitation signal mitigates this diffusion, similar to the effect of a cryostatic reduction of the cell temperature.

[0129] The species involved in the transfer process are indistinguishable from the environment at t = 0, and the frequency ω 1 and ω 2 The probability amplitudes of the environmental patterns are Z 10 and Z 20 The ambient patterns are assumed to evolve along deterministic trajectories determined by the dynamics of the classical excitation signal V acting on the patterns. Thus, the energy ω 1 and ω 2 The amplitude of the ambient mode at is described by its corresponding coherent state amplitude as:

[0130] and (7.4a)

[0131]

[0132] Here, ΔV is the thermal rms voltage fluctuation of the excitation signal, which is related to The corresponding initial conditions in Equations 7.2a and 7.2b will be modified to:

[0133] and (7.5a)

[0134]

[0135] At the ambient mode frequency ω 1 and ω 2 The surrounding diffusion It is determined whether the cell modes near the characteristic frequency can contribute to the evolution of the wave functions of subsystems 1 and 2 participating in the EET process. Minimization of the rms voltage noise at the reference node in the feedback loop or an equivalent reduction in the cell temperature reduces the contribution of these background processes to states 1 and 2. Thus, the environmentally induced scattering into and out of electronic states 1 and 2 is limited to the states with the energy ω 1 and ω 2 Resonant pool mode.

[0136] Solving the dynamical equations 7.2a and 7.2b yields the time evolution of the probability amplitudes for states 1 and 2:

[0137]

[0138] as well as For the ambient mode 1 and ω 2 The ideal initial condition of zero diffusion around. Due to the weakening of the dissipative coupling between state 1 and its surrounding modes as described above, the electronic state ω 1 The line width around is also minimized. Therefore, the fundamental EET process is confined to the electronic energy level of state 1 with frequency ω 2 Energy exchange between pool modes at , where the state energy levels of each participant are characterized by a narrow spread.

[0139] The participant electronic states also exchange energy with the pool modes, which resonate with the corresponding electronic energies. State 1, whose feedback reduces its dissipative coupling with the ambient modes, is also characterized by a persistent spectral coherence with the pool modes, which resonate with state 2, as seen in Eq. 7.6a. The dynamic variables Q that characterize the EET participants 1 、p 1 The interference between the electronic state observed in and the vibronic state enables the measurement of the vibronic structure of the complementary participant subjected to the energy scan. This measurement method is particularly useful in cases where direct measurement of the dynamic variables of the complementary participant during the EET process is not possible, such as in molecular electrochemical charge transfer systems, where State 2 characterizes redox-active molecules dissolved in a liquid electrolyte medium.

[0140] In summary, a feedback mechanism is proposed to attenuate the dissipation from the thermodynamic pool, thereby preserving the coherent interference between the participant states during the EET process. Classical circuit simulations are shown to characterize the effect of electronic feedback on the quantum EET system. Additionally, the dissipationless state can probe the vibronic properties of the complementary participant states by suppressing the rms voltage fluctuations between the two states using negative feedback. Example

[0141] A potentiostatic device with a feedback control system detects Staphylococcal enterotoxin B in an electrolyte containing redox-coupled potassium ferrocyanide (ii) / (iii). The concentration of the analyte in the electrolyte ranges from 1 pg / ml to 1 μg / ml. The potentiostatic device includes a counter electrode, a reference electrode, and a working electrode in electrical contact with the electrolyte. The counter electrode, the reference electrode, and the working electrode are made of metal (e.g., gold, platinum, platinum-iridium, silver, silver / silver chloride). The potentiostatic device detects the potential of redox-active species in the electrolyte at the reference electrode, and provides a low-noise, high-gain feedback current signal to the electrolyte through the counter electrode based on the detected potential. The charge in the current signal is carried between the counter electrode and the working electrode by monohydrogen phosphate and dihydrogen phosphate anions and potassium cations. The working electrode is grounded (i.e., connected to ground potential), and the charge received by the working electrode is transferred to the ground terminal.

[0142] The reference electrode is electrically coupled to a voltage buffer via an impedance. The voltage buffer includes an nMOS transistor cascaded with another nMOS transistor. The drain of the first nMOS transistor is connected to a potential +V B The voltage source is electrically connected, and the gate of the first nMOS transistor is connected through an impedance X 参考 The drain of the second nMOS transistor is electrically connected to the reference electrode through an impedance R B1 The source of the second nMOS transistor is electrically connected to the source of the nMOS transistor. B2 With potential -V B In addition, the gate of the nMOS transistor is electrically connected to a voltage source having a potential of -V B The potential at the drain of the second nMOS transistor is the output V of the voltage buffer. 测量 .

[0143] A pair of cascaded high-gain amplifiers can deliver a high-gain correction signal to the electrolyte through the counter electrode. The first high-gain amplifier receives a set potential V 设定 (at the inverting input terminal), and the output of the voltage buffer, V 测量 (at the non-inverting input terminal) as input. The output of the first gain amplifier is connected through a resistor R F1The output terminal of the first high gain amplifier is connected to the inverting input terminal of the first high gain amplifier. S2 The output terminal of the second high gain amplifier is electrically connected to the inverting input terminal of the second high gain amplifier. The non-inverting input terminal of the second amplifier is connected to the ground potential. The output terminal of the second high gain amplifier is connected to the ground potential through the resistor R F2 The output terminal of the second high-gain amplifier (corrective feedback current signal) is connected to the inverting input terminal of the second high-gain amplifier through the resistor X M Electrically connected to the counter electrode.

[0144] By measuring the resistor X using a low noise voltmeter or a transimpedance amplifier M The voltage across the two terminals is used to detect the corrective feedback current signal. The corrective feedback current signal determines the potential of the counter electrode and suppresses the dissipation acting on the charge transfer process and the thermal voltage fluctuations acting on the species in the electrolyte. The corrective feedback signal can thus influence the electron exchange process at the working electrode. When the set potential V 设定 When the voltage is set to V, the corrective feedback signal changes. 设定 The voltmeter is connected to a controller (e.g., a general purpose computer) which changes the set potential V 设定 The controller then generates current vs. voltage data for the electrolyte with the analyte. The analysis routine then compares the properties in the acquired IV trace with the properties in the reference database to ascertain the identity of the analyte.

Claims

1. A system, include: (a) a plurality of electrodes configured to be electrically coupled to a sample; as well as (b) a feedback mechanism coupled to a first electrode of the plurality of electrodes and configured to detect an electrical potential associated with the sample through the first electrode, wherein the feedback mechanism provides a feedback signal to the sample through a second electrode of the plurality of electrodes, and the feedback signal is configured to provide excitation control of the sample at a third electrode of the plurality of electrodes, The feedback mechanism includes: a first negative feedback amplifier configured to generate a first signal based on a difference between a voltage signal indicating a detected potential associated with the sample and a set potential value, The feedback mechanism includes: a second negative feedback amplifier configured to receive the first signal and generate the feedback signal, The excitation signal applied to the feedback mechanism includes a high-frequency part characterizing the energy difference between the states of two participants of the quantum mechanical charge transfer system and a low-frequency signal describing the time response of the feedback mechanism.

2. The system of claim 1, in, The sample is a charge transfer system at the molecular level.

3. The system of claim 2, in, The feedback signal provides excitation control of the molecular scale charge transfer system during an electron excitation transfer (EET) process in the molecular scale charge transfer system.

4. The system of claim 2 or claim 3, in, This excitation control attenuates the dissipation of the charge transfer system at this molecular scale from the surrounding thermodynamic pool.

5. The system of any one of claims 2, 3 or 4, in, The excitation control reduces the dissipative coupling of one or more electronic vibrational energy levels in the charge transfer system at the molecular scale to the external pool.

6. The system of claim 1 or claim 5, in, The first, second and third electrodes are the reference electrode, the counter electrode and the working electrode of the potentiostat, respectively.

7. The system of claim 2 or claim 5, include: A current detection system is configured to detect a current associated with the second electrode.

8. The system of claim 7, in, The detected current is indicative of the analyte in the charge transfer system at that molecular scale.

9. A method for detecting an analyte, include: (a) detecting, by a feedback mechanism, an electrical potential associated with a sample through a first electrode of a plurality of electrodes, wherein the plurality of electrodes are electrically coupled to the sample; (b) generating a feedback signal by the feedback mechanism, wherein the feedback mechanism comprises: a first negative feedback amplifier configured to generate a first signal based on a difference between a voltage signal indicating a detected potential associated with the sample and a set potential value, and a second negative feedback amplifier configured to receive the first signal and generate the feedback signal; and (c) providing the feedback signal to the sample via a second electrode of the plurality of electrodes, the feedback signal being configured to provide excitation control of the sample at a third electrode of the plurality of electrodes, The excitation signal applied to the feedback mechanism includes a high-frequency part characterizing the energy difference between the states of two participants of the quantum mechanical charge transfer system and a low-frequency signal describing the time response of the feedback mechanism.

10. The method of claim 9, in, The sample is a charge transfer system at the molecular level.

11. The method of claim 10, in, The feedback signal provides excitation control of the molecular scale charge transfer system during an electron excitation transfer (EET) process in the molecular scale charge transfer system.

12. The method of claim 10 or claim 11, in, This excitation control attenuates the dissipation of the charge transfer system at this molecular scale from the surrounding thermodynamic pool.

13. The method of any one of claims 10, 11 or 12, in, The excitation control reduces the dissipative coupling of one or more electronic vibrational energy levels in the charge transfer system at the molecular scale to the external pool.

14. The method of claim 9 or claim 13, in, The first, second and third electrodes are the reference electrode, the counter electrode and the working electrode of the potentiostat, respectively.

15. The method of claim 10 or claim 13, include: A current detection system is configured to detect a current associated with the second electrode.

16. The method of claim 15, in, The detected current is indicative of the analyte in the charge transfer system at that molecular scale.

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