Ion trap chip parameter correction method and device, electronic equipment and medium

Abstract

The present disclosure provides a method, device, electronic device, computer-readable storage medium and computer program product for correcting parameters of an ion trap chip, and relates to the field of quantum computers, and in particular to the field of ion trap chip technology. The implementation scheme is: determining the intrinsic phonon frequency of the first ion in the ion trap chip; performing the following operations multiple times: adjusting the power value of the laser and determining the equivalent amplitude after the laser irradiates the first ion at the current power value; obtaining and setting the second pulse duration of the laser, changing the frequency difference between the two laser beams divided by the laser through the beam splitter, so as to determine the second probability that the first ion is in an excited state at each frequency difference; determining the first phonon frequency based on the change of the second probability with the frequency difference; determining the difference between the first phonon frequency and the intrinsic phonon frequency; and performing function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so as to correct the phonon frequency at the corresponding equivalent amplitude based on the fitting function.

Description

Technical Field

[0001] The present disclosure relates to the field of quantum computers, in particular to the field of ion trap chip technology, and specifically to an ion trap chip parameter correction method, device, electronic device, computer-readable storage medium and computer program product. Background Art

[0002] Ion trap quantum computing is a computing method based on quantum mechanics. Its principle is to use the stable movement of ions in an electric field to process information as quantum bits. Through the precise control of laser and microwave fields, quantum gate operations can be realized, thereby performing quantum computing. This method is currently considered to be one of the promising ways to achieve quantum computing.

[0003] The basic process of ion trap quantum computing is to use lasers to cool ions and form a bound potential in space through direct current and alternating electric fields, so that the ions can be stationary at a point in three-dimensional space, and then adjust the laser to achieve quantum entanglement and manipulation between ions. Since each ion can be abstracted as a quantum bit, many important tasks in quantum computing can be achieved by manipulating them, such as quantum random walks, quantum simulations, and quantum searches. Ion trap quantum computing is highly controllable, can implement efficient quantum algorithms, and has broad application prospects. At the same time, ion trap quantum computing has very high requirements for experimental technology, requiring precise control of the position, energy level, and interaction of ions, as well as high-precision measurement and control of ions. Summary of the invention

[0004] The present disclosure provides an ion trap chip parameter correction method, device, electronic device, computer-readable storage medium and computer program product.

[0005] According to one aspect of the present disclosure, a method for correcting parameters of an ion trap chip is provided, comprising: determining the position of a first ion to be calibrated in the ion trap chip; obtaining and setting an initial power value of a laser so that an equivalent amplitude after the laser irradiates the first ion is less than a first threshold value; obtaining and setting a first pulse duration of the laser, and changing a frequency difference between two laser beams split by a beam splitter to determine a first probability that the first ion is in an excited state at each frequency difference; determining an intrinsic phonon frequency based on a change in the first probability with the frequency difference; performing the following operations N times, where N is a positive integer greater than or equal to 2: adjusting the laser pulse duration; and determining a first probability that the first ion is in an excited state at each frequency difference. The invention relates to a method for obtaining a power value of an optical device, and determining an equivalent amplitude after the laser irradiates the first ion at the current power value; obtaining and setting a second pulse duration of the laser, and changing the frequency difference between the two laser beams into which the laser is divided by a beam splitter, so as to determine a second probability that the first ion is in an excited state at each frequency difference; determining a first phonon frequency based on a change of the second probability with the frequency difference; determining a difference between the first phonon frequency and the intrinsic phonon frequency; and performing function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so as to correct the phonon frequency at the corresponding equivalent amplitude based on the fitted function.

[0006] According to another aspect of the present disclosure, an ion trap chip parameter correction device is provided, comprising: a first determination unit, configured to determine the position of a first ion to be calibrated in the ion trap chip; an acquisition unit, configured to acquire and set an initial power value of a laser, so that the equivalent amplitude after the laser irradiates the first ion is less than a first threshold value; a second determination unit, configured to acquire and set a first pulse duration of the laser, and change the frequency difference between two laser beams into which the laser is split by a beam splitter, so as to determine a first probability that the first ion is in an excited state at each frequency difference; a third determination unit, configured to determine an intrinsic phonon frequency based on a change in the first probability with the frequency difference; and an execution unit, configured to perform the following operations N times, N is a positive integer greater than or equal to 2: adjusting the power value of the laser, and determining the equivalent amplitude after the laser irradiates the first ion at the current power value; acquiring and setting the second pulse duration of the laser, and changing the frequency difference between the two laser beams divided by the laser through the beam splitter, so as to determine the second probability that the first ion is in an excited state at each frequency difference; determining the first phonon frequency based on the change of the second probability with the frequency difference; determining the difference between the first phonon frequency and the intrinsic phonon frequency; and a correction unit, configured to perform function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so that the phonon frequency at the corresponding equivalent amplitude is corrected based on the fitted function.

[0007] According to another aspect of the present disclosure, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the method described in the present disclosure.

[0008] According to another aspect of the present disclosure, a non-transitory computer-readable storage medium storing computer instructions is provided. The computer instructions are used to cause a computer to execute the method described in the present disclosure.

[0009] According to another aspect of the present disclosure, a computer program product is provided, including a computer program, which implements the method described in the present disclosure when executed by a processor.

[0010] According to one or more embodiments of the present disclosure, the equivalent amplitude and phonon frequency are correlated and calibrated, and the relationship between the corresponding equivalent amplitude and the difference is fitted, so that the relevant phonon frequency can be corrected based on the difference, so that the phonon frequency calibration is more accurate, and the corrected phonon frequency can be better suitable for ion trap experiments, providing a guarantee for the accuracy of the experimental results.

[0011] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings exemplarily illustrate the embodiments and constitute a part of the specification, and together with the text description of the specification, are used to explain the exemplary implementation of the embodiments. The embodiments shown are for illustrative purposes only and do not limit the scope of the claims. In all drawings, the same reference numerals refer to similar but not necessarily identical elements.

[0013] Figure 1 A flow chart of a method for correcting ion trap chip parameters according to an embodiment of the present disclosure is shown;

[0014] Figure 2 A schematic diagram showing the determination of ion positions by scanning laser and fluorescence imaging according to an embodiment of the present disclosure is shown;

[0015] Figure 3 A schematic diagram showing possible transitions after coupling of ions and phonons according to an embodiment of the present disclosure is shown;

[0016] Figure 4 A schematic diagram showing a blue sideband transition frequency sweep result and a baseline model theoretical fitting result according to an embodiment of the present disclosure is shown;

[0017] Figure 5 A schematic diagram of determining the phonon frequency based on a frequency sweep experiment according to an embodiment of the present disclosure is shown;

[0018] Figure 6 A structural block diagram of an ion trap chip parameter correction device according to an embodiment of the present disclosure is shown; and

[0019] Figure 7 A structural block diagram of an exemplary electronic device that can be used to implement the embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0020] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present disclosure. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0021] In the present disclosure, unless otherwise specified, the use of the terms "first", "second", etc. to describe various elements is not intended to limit the positional relationship, timing relationship, or importance relationship of these elements, and such terms are only used to distinguish one element from another element. In some examples, the first element and the second element may refer to the same instance of the element, and in some cases, based on the description of the context, they may also refer to different instances.

[0022] The terms used in the description of various examples in this disclosure are only for the purpose of describing specific examples and are not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element can be one or more. In addition, the term "and / or" used in this disclosure covers any one of the listed items and all possible combinations.

[0023] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0024] So far, all the different types of computers in use are based on classical physics as the theoretical basis for information processing, and are called traditional computers or classical computers. Classical information systems use binary data bits, which are the easiest to implement physically, to store data or programs. Each binary data bit is represented by 0 or 1, called a bit or bit, as the smallest unit of information. Classical computers themselves have inevitable weaknesses: one is the most basic limitation of energy consumption in the computing process. The minimum energy required for logic elements or storage units should be several times more than kT to avoid misoperation due to thermal expansion and fall; the second is information entropy and heat energy consumption; the third is that when the wiring density of computer chips is very high, according to the Heisenberg uncertainty relation, when the uncertainty of the electron position is very small, the uncertainty of the momentum will be very large. Electrons are no longer bound, and there will be quantum interference effects, which may even destroy the performance of the chip.

[0025] A quantum computer is a physical device that follows the properties and laws of quantum mechanics to perform high-speed mathematical and logical operations, store and process quantum information. When a device processes and calculates quantum information and runs quantum algorithms, it is a quantum computer. Quantum computers follow the unique laws of quantum dynamics (especially quantum interference) to achieve a new mode of information processing. For parallel processing of computational problems, quantum computers have an absolute advantage in speed over classical computers. The transformation of each superposition component by a quantum computer is equivalent to a classical calculation. All these classical calculations are completed at the same time and superimposed according to a certain probability amplitude to give the output result of the quantum computer. This calculation is called quantum parallel computing. Quantum parallel processing greatly improves the efficiency of quantum computers, allowing them to complete tasks that classical computers cannot complete, such as factoring a large natural number. Quantum coherence is essentially used in all quantum ultra-fast algorithms. Therefore, quantum parallel computing, which replaces classical states with quantum states, can achieve computing speeds and information processing functions that are incomparable to classical computers, while saving a lot of computing resources.

[0026] In order to achieve high-performance ion trap quantum computing, parameter calibration of the ion trap system is crucial. In order to achieve high-fidelity quantum operations, researchers need to accurately calibrate the parameters of the ion trap system, including lasers, phonon frequencies, and interactions between ions.

[0027] In ion trap quantum control, each ion in the trap represents a quantum bit, and the two internal states of the ion |↓>, |↑> can be exactly represented as the quantum bit's |0>, |1> states. If two quantum bits need to be entangled, it is often necessary to guide the laser to irradiate the two ions. The two ions acted upon by the laser interact with each other in charge Coulomb and share the quantized phonon mode in the ion chain. For such an experimental system, its equivalent Hamiltonian is generally related to the parameters of the ion trap system, including the laser frequency, amplitude and phase, phonon frequency, coupling strength, etc. Among them, in experiments, the amplitude and phase of the laser pulse are generally adjusted to achieve the adjustment of the equivalent Hamiltonian.

[0028] Therefore, in quantum operations based on the ion trap system, corresponding quantum operations can be implemented based on the calibrated parameters. For example, laser pulses are modulated based on more accurate system parameters, and more accurate quantum gates are obtained by applying laser pulses to corresponding ions, thereby implementing more accurate quantum computing operations based on the obtained quantum gates. Therefore, the precise calibration of these parameters can improve the efficiency and accuracy of quantum operations in ion traps, thereby improving the performance of ion trap quantum computing.

[0029] Among these parameters to be calibrated, the collective vibration mode of the ion trap, the phonon frequency, is particularly important. This is because in ion trap quantum computing, the generation of dual-bit and multi-bit quantum gates requires precise operation and control of ions, and after each operation of the quantum circuit, phonons need to be used for cooling and reset, all of which are inseparable from the calibration of the phonon frequency.

[0030] Theoretically, the phonon frequency corresponding to the collective vibration of ions in an ion trap is limited. The limitation of phonon frequency is caused by the Coulomb interaction between ions and the interaction between the positions of each ion in the steady state. These interactions cause the collective vibration of ions to form some specific frequency modes, which can be excited and adjusted by precisely controlling the frequency and power of the laser. Therefore, the value of the phonon frequency corresponding to the collective vibration of ions in the ion trap can be used to precisely control the position and momentum of the ions. Operations in ion trap quantum computing often require precise control of the interactions between ions and the positions of ions, so it is necessary to precisely control the phonon frequency in the ion trap. If there is an error in the calibration of the phonon frequency, the interaction between ions will cause errors and noise in the calculation, thereby affecting the accuracy and reliability of the entire calculation. Therefore, the accurate value of the phonon frequency is one of the keys to ensure high efficiency and accuracy in ion trap quantum computing.

[0031] In the ion trap experiment, the built ion trap system needs to be calibrated. A more accurate method is the Ramsey interferometry. The Ramsey interferometry is a measurement method based on quantum interference. By adjusting the free evolution time and observing the periodic changes of the interference fringes, the energy difference between the internal energy levels of atoms or ions can be measured. In the ion trap experiment, the Ramsey interferometry can be used to measure the phonon frequency of ions. The specific operation method is: prepare an atom or ion from one energy level to another, then let it evolve freely for a period of time, and finally convert it back to the prepared state. If the two ions are at the same energy level, they will interfere and produce interference fringes; if the two ions are at different energy levels, they will not interfere and no interference fringes will be produced. By adjusting the free evolution time, the periodic changes of the interference fringes can be observed. According to the period of the interference fringes, the phonon frequency of the ion can be calculated.

[0032] However, the sensitivity of Ramsey interferometry is limited by the free evolution time. A shorter free evolution time will result in a decrease in the visibility of the interference fringes, while a longer free evolution time will cause the periodic changes of the interference fringes to become less obvious. Ramsey interferometry requires high-precision lasers and control systems as well as stable environmental conditions to obtain high-precision phonon frequency calibration results. Factors such as environmental noise or temperature changes may affect the experimental results. Ramsey interferometry requires multiple experiments to determine the phonon frequency, which increases the complexity and time-consuming nature of the experiment. In addition, Ramsey interferometry also requires the ion trap to have a high quality factor and a long lifetime to ensure the stability of the interference fringes. This places certain requirements on the preparation and adjustment of the ion trap.

[0033] Therefore, according to an embodiment of the present disclosure, a method for correcting ion trap chip parameters is provided. Figure 1 FIG. 4 shows a flow chart of a method for correcting ion trap chip parameters according to an embodiment of the present disclosure, as shown in FIG. Figure 1As shown, the method 100 includes: determining the position of the first ion to be calibrated in the ion trap chip (step 110); obtaining and setting the initial power value of the laser so that the equivalent amplitude after the laser irradiates the first ion is less than a first threshold value (step 120); obtaining and setting the first pulse duration of the laser, and changing the frequency difference between the two laser beams divided by the laser through the beam splitter to determine the first probability that the first ion is in an excited state at each frequency difference (step 130); determining the intrinsic phonon frequency based on the change of the first probability with the frequency difference (step 140); performing the following operations N times, where N is a positive integer greater than or equal to 2 (step 150): adjusting the power value of the laser, and determining the current The invention relates to an embodiment of the present invention, wherein the first ion is irradiated with the laser at a power value of 0.1 % after being irradiated by the laser to the first ion (step 1501); obtaining and setting a second pulse duration of the laser, and changing the frequency difference between the two laser beams divided by the laser through a beam splitter to determine a second probability that the first ion is in an excited state at each frequency difference (step 1502); determining a first phonon frequency based on a change in the second probability with the frequency difference (step 1503); determining a difference between the first phonon frequency and the intrinsic phonon frequency (step 1504); and performing function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so that the phonon frequency at the corresponding equivalent amplitude is corrected based on the fitted function (step 160).

[0034] According to the embodiments of the present disclosure, the equivalent amplitude and the phonon frequency are correlated and calibrated, and the relationship between the corresponding equivalent amplitude and the difference is fitted, so that the relevant phonon frequency can be corrected based on the difference, so that the phonon frequency calibration is more accurate, and the corrected phonon frequency can be better suitable for ion trap experiments, thereby improving the accuracy of the experimental results.

[0035] Due to the particularity of ion trap quantum computing, the ions that serve as quantum bits float in the space of 10 to 100 μm above the ion trap chip. The distance between each two ions is related to the total number of ions, which is about 2 to 10 μm. The ions are generally not equidistant, showing the characteristics of dense in the middle and sparse on both sides. As the first step of ion trap quantum computing, it is necessary to find the location of the quantum bit in space before subsequent quantum operations can be performed.

[0036] In some embodiments, determining the position of a first ion to be calibrated in the ion trap chip includes: changing the incident angle of the laser within a first preset range according to a first preset step size to determine the position of the first ion by fluorescence imaging.

[0037] In some examples, multiple ions in an ion trap can be scanned one by one by a scanning laser method to find the positions of each of the multiple ions. Scanning laser method, that is, if there are multiple ions in an ion trap, a laser can be used to scan the ions one by one. The position of the ion can be found by changing the incident position of the laser beam and monitoring the fluorescence signal. When the laser beam coincides with an ion, the fluorescence signal changes significantly, thereby determining the position of the ion. Figure 2 A schematic diagram of determining the position of ions (qubits) by scanning laser and fluorescence imaging according to an embodiment of the present disclosure is shown.

[0038] Specifically, the position of ions can be calibrated by fluorescence imaging and scanning laser beams. By laser cooling and exciting ions to a higher energy level, the ions emit fluorescent photons and de-excite back to the ground state. These fluorescent photons can be collected and detected by an imaging system such as an optical microscope and a photomultiplier tube or a charge-coupled device (CCD) camera. Since the intensity of the fluorescence signal is related to the degree of overlap between the ion position and the laser beam, the position of the ion can be found by processing and analyzing the collected fluorescence imaging.

[0039] It is understandable that the ions have a slight movement in their corresponding positions, so the determined position of the ions can also be called the central position, which is not limited here.

[0040] In some embodiments, obtaining and setting an initial power value of the laser so that the equivalent amplitude after the laser is irradiated to the first ion is less than a first threshold value includes: adjusting the power value of the laser until the determined equivalent amplitude is less than the first threshold value and determining the power value corresponding to the equivalent amplitude being less than the first threshold value as the initial power value; determining the frequency difference between the |g> state and the |e> state of the first ion to determine the frequency difference between the two laser beams divided by the laser through a beam splitter based on the frequency difference; adjusting the pulse duration of the laser and determining the probability that the first ion is in an excited state after the laser is irradiated to the first ion at each pulse duration; determining a third pulse duration corresponding to a probability that the first ion is in an excited state is close to 1; and determining the equivalent amplitude after the laser is irradiated to the first ion based on the third pulse duration.

[0041] According to some embodiments, the equivalent amplitude Ω after the laser irradiates the first ion is determined based on the following formula:

[0042] Ω=π / 2τ

[0043] Wherein, τ is the duration of the third pulse.

[0044] In some examples, after the position of the first ion is determined, the frequency difference of the two opposing laser beams can be modulated to be the same as the frequency difference between the internal states of the first ion, the |g> state and the |e> state, and the number of the first ion in the |e> state (excited state) is observed to change with time by continuously changing the pulse duration τ of the laser action, until the probability of the first ion in the |e> state is close to 1 after the laser pulse duration τ. In this way, the equivalent amplitude (i.e., Rabi drive strength) after the laser irradiates the first ion can be calibrated to Ω=π / 2τ.

[0045] According to some embodiments, the first threshold comprises 0.01 MHz.

[0046] It is understandable that a corresponding first threshold can be set according to a specific ion trap chip or actual needs, so that when the equivalent amplitude is smaller than the threshold, it can be assumed that the laser is difficult to couple the first ion with the phonon and the phonon frequency is close to its intrinsic frequency.

[0047] According to some embodiments, the first pulse duration is greater than the second pulse duration.

[0048] It can be seen from the above that the equivalent amplitude (i.e., Rabi drive intensity) is inversely proportional to the laser pulse duration. Therefore, when the equivalent amplitude is small, a longer pulse duration τ can be selected to change the frequency difference between the two laser beams split by the laser through the beam splitter, determine the first probability of the first ion being in the excited state at each frequency difference, and then determine the intrinsic phonon frequency.

[0049] Due to the problems of the Ramsey interferometer method being complicated and time-consuming, in the embodiment of the present disclosure, the phonon frequency of the ion is measured by using a laser frequency sweep method. Specifically, by adjusting the frequency of the excitation signal (i.e., the frequency difference between the two laser beams) through a laser frequency sweeper and observing the change in ion fluorescence, the number of configurations of the ion in the excited state can be obtained.

[0050] In the example of determining the phonon frequency through a frequency sweep experiment, when the frequency difference between the two laser beams split by the laser through the beam splitter is close to the phonon frequency, an obvious peak will appear. Therefore, the frequency difference corresponding to the peak of the first probability can be determined as the corresponding phonon frequency.

[0051] Similarly, according to some embodiments, determining the equivalent amplitude after the laser irradiates the first ion at the current power value includes: determining the frequency difference between the |g> state and the |e> state of the first ion, so as to determine the frequency difference between the two laser beams divided by the laser through the beam splitter based on the frequency difference; adjusting the pulse duration of the laser, and determining the probability that the first ion is in an excited state after the laser irradiates the first ion at each pulse duration; determining a fourth pulse duration corresponding to a probability that the first ion is in an excited state close to 1; and determining the equivalent amplitude after the laser irradiates the first ion based on the fourth pulse duration.

[0052] According to some embodiments, the equivalent amplitude Ω after the laser irradiates the first ion is determined based on the following formula:

[0053] Ω=π / 2τ

[0054] Here, τ is the duration of the fourth pulse.

[0055] According to some embodiments, acquiring and setting the second pulse duration of the laser includes: setting the second pulse duration to be equal to the fourth pulse duration or close to the fourth pulse duration within a preset error range.

[0056] In some embodiments, after calibrating one ion (i.e., the first ion), the laser incident angle can be changed to address the next first ion to be calibrated, and the corresponding calibration process can be repeated to complete the functional relationship between the equivalent amplitude of the next ion and the corresponding phonon frequency difference until all ions are calibrated.

[0057] In some examples, after obtaining the functional relationship between the equivalent amplitude obtained by fitting and the corresponding difference, the quantum frequency corresponding to the corresponding ions in the same or similar ion trap chip can be corrected based on the functional relationship. For example, in some experiments, the intrinsic phonon frequency is required, but the phonon frequency calibrated by the user is not its intrinsic frequency. Since in the calibration of ion trap chip parameters, it is usually necessary to calibrate the equivalent amplitude and further calibrate the phonon frequency on this basis, the frequency difference corresponding to the equivalent amplitude calibrated by the user can be determined according to the equivalent amplitude calibrated by the user and the functional relationship obtained according to the embodiment of the present disclosure, and then the corresponding intrinsic frequency can be obtained by subtracting the frequency difference from the phonon frequency calibrated by the user. For another example, the manufacturer gives the corresponding phonon frequency, but in the user's experiment, due to the influence of the laser power, phase, amplitude, etc. used, its actual phonon frequency is different from the given phonon frequency. Therefore, the frequency difference corresponding to the equivalent amplitude calibrated by the user can be determined based on the equivalent amplitude calibrated in the user experiment and the functional relationship obtained according to the embodiment of the present disclosure, and then the actual phonon frequency in the current user experiment can be obtained by adding the frequency difference to the given phonon frequency.

[0058] It is understandable that the above correction of the quantum frequency corresponding to the corresponding ions in the same or similar ion trap chip based on the functional relationship is only exemplary. In real physical experiments, users can obtain more accurate phonon frequencies under corresponding equivalent amplitudes based on the functional relationship according to their experimental needs, and there is no limitation here.

[0059] In some frequency sweep experiments, when determining the phonon frequency based on the number of configurations (i.e., probability) of ions in an excited state, the difference between the observed frequency corresponding to the first blue-sideband transition peak (i.e., the frequency difference between the two laser beams split by the beam splitter) and the frequency corresponding to the main transition peak is usually regarded as the phonon frequency. However, only the blue-sideband transition is considered at this time, while the influence of the main transition and the red-sideband transition on the results is ignored; and only the two-level system is considered, i.e., |g>|n> and |g>|n+1>, while the actual ion trap system has multiple energy levels.

[0060] Therefore, in some embodiments, the method according to the present disclosure further includes: determining a Hamiltonian expression of a quantum system corresponding to the first ion, so as to determine the respective probabilities that the first ion is in an excited state based on the Hamiltonian expression. The Hamiltonian expression includes a term corresponding to a blue sideband transition, a term corresponding to a red sideband transition, and a term corresponding to a main transition.

[0061] As mentioned above, the difference between the first blue sideband transition frequency and the main transition frequency is usually directly read as the phonon frequency. However, in reality, only the blue sideband transition is considered, while the main transition and red sideband transition are ignored, so there will be a deviation between the calibrated phonon frequency and the actual value.

[0062] In the embodiment according to the present disclosure, the influence of three transitions is considered at the same time, and the corresponding complete Hamiltonian is as follows:

[0063]

[0064] Among them, j and k are ion and phonon indicators respectively, Ω j is the equivalent Rabi drive frequency (i.e. equivalent amplitude), is the upgrading operator of the jth ion from the |g> state to the |e> state, It represents the large detuning of the two laser beams split by the beam splitter, that is, the frequency difference between the two laser beams, which is generally a variable that can be controlled in the frequency sweep experiment. j,k is the strength of the coupling between ions and phonons, a k is the annihilation operator of the phonon, ω k is the frequency of the phonon and is also the main object to be calibrated. hc represents the conjugate term.

[0065] As above, the Hamiltonian is j,k When it is small, it can be expanded into the following form:

[0066]

[0067] When Δ j = 0, people generally ignore the high-frequency terms behind, and the Hamiltonian is only term, called the main transition. j ≈ω k When the Hamiltonian is approximately term, called blue sideband transition. j ≈-ω k When the Hamiltonian is approximately The above three transitions are generally all the terms that people currently consider. The corresponding transition diagram is as follows Figure 3 shown.

[0068] When only the blue sideband transition is considered, after the Hamiltonian of the interaction between the laser and the two-level system evolves over time t, the probability of the ion being in the |e> state can be conveniently calculated based on the corresponding Hamiltonian:

[0069]

[0070] Among them, the result of the frequency sweep deviates from the actual situation, which is called "frequency drift". Figure 4 shown.

[0071] In the above embodiment, the Hamiltonian expression used takes into account the three transitions, so based on the Hamiltonian, the number of layouts in the excited state can be calculated as it changes with the laser frequency difference. It should be noted that equipment (such as fluorescence detection equipment) for observing the number of layouts (probability) of ions in the excited state can be easily obtained. In the simulation experiment, the change in the number of layouts of ions in the excited state under different laser parameters can be calculated based on the determined Hamiltonian. Therefore, by calculating the change in the number of excited state layouts with frequency, the three layout numbers of the main red and blue |e>|n>, |e>|n-1>, and |e>|n+1> and the total |e> state layout number can be recorded, such as Figure 5 shown.

[0072] As described above, in the example of determining the phonon frequency by frequency sweeping experiment, the frequency difference corresponding to the first probability peak can be determined as the corresponding phonon frequency. Figure 5 In the example shown, the first probability peak generally corresponds to the peak corresponding to the blue sideband transition. Therefore, the frequency difference corresponding to the peak in the region where the frequency difference is greater than 0 (i.e., the peak corresponding to the blue sideband transition) can be read as the corresponding phonon frequency.

[0073] In the above embodiment, the influence of the main transition, the red transition and the blue transition is retained in the Hamiltonian expression, and the calibration result is more consistent with the actual experimental situation, and the calibrated parameters are closer to the actual experimental parameters.

[0074] According to the embodiments of the present disclosure, Figure 6As shown, an ion trap chip parameter correction device 600 is also provided, including: a first determination unit 610, configured to determine the position of the first ion to be calibrated in the ion trap chip; an acquisition unit 620, configured to acquire and set the initial power value of the laser, so that the equivalent amplitude after the laser irradiates the first ion is less than a first threshold value; a second determination unit 630, configured to acquire and set the first pulse duration of the laser, and change the frequency difference between the two laser beams divided by the laser through the beam splitter to determine the first probability that the first ion is in an excited state at each frequency difference; a third determination unit 640, configured to determine the intrinsic phonon frequency based on the change of the first probability with the frequency difference; an execution unit 650, configured to execute the following The operation is performed N times, where N is a positive integer greater than or equal to 2: adjusting the power value of the laser, and determining the equivalent amplitude after the laser irradiates the first ion at the current power value; acquiring and setting the second pulse duration of the laser, and changing the frequency difference between the two laser beams divided by the laser through the beam splitter, so as to determine the second probability that the first ion is in an excited state at each frequency difference; and determining the first phonon frequency based on the change of the second probability with the frequency difference; determining the difference between the first phonon frequency and the intrinsic phonon frequency; and a correction unit 660, configured to perform function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so that the phonon frequency at the corresponding equivalent amplitude is corrected based on the fitted function.

[0075] Here, the operations of the above-mentioned units 610 to 660 of the ion trap chip parameter correction device 600 are similar to the operations of the above-described steps 110 to 160, and will not be described in detail here.

[0076] According to an embodiment of the present disclosure, an electronic device, a readable storage medium and a computer program product are also provided.

[0077] refer to Figure 7 , a block diagram of an electronic device 700 that can be used as a server or client of the present disclosure will now be described, which is an example of a hardware device that can be applied to various aspects of the present disclosure. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present disclosure described and / or required herein.

[0078] like Figure 7 As shown, the electronic device 700 includes a computing unit 701, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 702 or a computer program loaded from a storage unit 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the electronic device 700 can also be stored. The computing unit 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0079] Multiple components in the electronic device 700 are connected to the I / O interface 705, including: an input unit 706, an output unit 707, a storage unit 708, and a communication unit 709. The input unit 706 can be any type of device that can input information to the electronic device 700. The input unit 706 can receive input digital or character information and generate key signal input related to user settings and / or function control of the electronic device, and can include but is not limited to a mouse, a keyboard, a touch screen, a track pad, a track ball, a joystick, a microphone, and / or a remote controller. The output unit 707 can be any type of device that can present information, and can include but is not limited to a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 708 can include but is not limited to a disk, an optical disk. The communication unit 709 allows the electronic device 700 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can include but is not limited to a modem, a network card, an infrared communication device, a wireless communication transceiver, and / or a chipset, such as a Bluetooth device, an 802.11 device, a WiFi device, a WiMax device, a cellular communication device, and / or the like.

[0080] The computing unit 701 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 701 performs the various methods and processes described above, such as method 100. For example, in some embodiments, the method 100 may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 708. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 700 via the ROM 702 and / or the communication unit 709. When the computer program is loaded into the RAM 703 and executed by the computing unit 701, one or more steps of the method 100 described above may be performed. Alternatively, in other embodiments, the computing unit 701 may be configured to perform the method 100 in any other appropriate manner (e.g., by means of firmware).

[0081] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0082] The program code for implementing the method of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0083] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0084] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0085] The systems and techniques described herein can be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), the Internet, and a blockchain network.

[0086] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0087] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in this disclosure can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this document does not limit this.

[0088] Although the embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above-mentioned methods, systems and devices are merely exemplary embodiments or examples, and the scope of the present invention is not limited by these embodiments or examples, but only by the claims after authorization and their equivalent scope. Various elements in the embodiments or examples can be omitted or replaced by their equivalent elements. In addition, each step can be performed in an order different from that described in the present disclosure. Further, the various elements in the embodiments or examples can be combined in various ways. It is important that with the evolution of technology, many elements described herein can be replaced by equivalent elements that appear after the present disclosure.

Claims

1. A method for correcting ion trap chip parameters, comprising: Determining the position of a first ion to be calibrated in the ion trap chip; Acquiring and setting an initial power value of a laser so that an equivalent amplitude after the laser irradiates the first ion is less than a first threshold value; Acquire and set a first pulse duration of the laser, and change a frequency difference between two laser beams split by the laser through a beam splitter to determine a first probability that the first ion is in an excited state at each frequency difference; determining an intrinsic phonon frequency based on a change in the first probability as a function of the frequency difference; Perform the following operation N times, where N is a positive integer greater than or equal to 2: adjusting the power value of the laser, and determining the equivalent amplitude after the laser irradiates the first ion at the current power value; Acquire and set a second pulse duration of the laser, and change a frequency difference between two laser beams split by the laser through a beam splitter to determine a second probability that the first ion is in an excited state at each frequency difference; determining a first phonon frequency based on a change in the second probability as a function of the frequency difference; Determine the difference between the first phonon frequency and the intrinsic phonon frequency; and perform function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so that the phonon frequency under the corresponding equivalent amplitude is corrected based on the fitted function.

2. The method of claim 1, wherein: Acquiring and setting an initial power value of a laser so that an equivalent amplitude after the laser irradiates the first ion is less than a first threshold value includes: The power value of the laser is adjusted until the determined equivalent amplitude is less than a first threshold value and the power value corresponding to when the equivalent amplitude is less than the first threshold value is determined as an initial power value: Determine a frequency difference between the |g> state and the |e> state of the first ion, and determine a frequency difference between two laser beams split by the laser through a beam splitter based on the frequency difference; adjusting a pulse duration of the laser and determining a probability that the first ion is in an excited state after the first ion is irradiated by the laser at each pulse duration; determining a third pulse duration corresponding to a probability that the first ion is in an excited state close to 1; and An equivalent amplitude after the laser irradiates the first ions is determined based on the third pulse duration.

3. The method of claim 1, wherein: The first pulse duration is greater than the second pulse duration.

4. The method of claim 1, wherein: The first threshold is 0.01 MHz.

5. The method of claim 1, wherein: Determining the position of a first ion to be calibrated in the ion trap chip includes: changing the incident angle of the laser within a first preset range according to a first preset step length, so as to determine the position of the first ion through fluorescence imaging.

6. The method of claim 1, further comprising: determining a Hamiltonian expression of a quantum system corresponding to the first ion, so as to determine, based on the Hamiltonian expression, respective probabilities that the first ion is in an excited state, The Hamiltonian expression includes a term corresponding to a blue sideband transition, a term corresponding to a red sideband transition, and a term corresponding to a main transition.

7. The method of claim 1, wherein: Determining the equivalent amplitude of the laser after irradiating the first ion at the current power value includes: Determine a frequency difference between the |g> state and the |e> state of the first ion, and determine a frequency difference between two laser beams split by the laser through a beam splitter based on the frequency difference; adjusting a pulse duration of the laser and determining a probability that the first ion is in an excited state after the first ion is irradiated by the laser at each pulse duration; determining a fourth pulse duration corresponding to a probability that the first ion is in an excited state close to 1; and An equivalent amplitude after the laser irradiates the first ions is determined based on the fourth pulse duration.

8. The method of claim 7, wherein: Acquiring and setting the second pulse duration of the laser includes: setting the second pulse duration to be equal to the fourth pulse duration or to be close to the fourth pulse duration within a preset error range.

9. The method according to claim 2 or 7, wherein: The equivalent amplitude Ω after the laser irradiates the first ion is determined based on the following formula: Ω=π / 2τ Wherein, τ is the corresponding pulse duration corresponding to the probability that the first ion is in the excited state is close to 1.

10. An ion trap chip parameter correction device, comprising: A first determining unit, configured to determine the position of a first ion to be calibrated in the ion trap chip; an acquisition unit, configured to acquire and set an initial power value of the laser so that an equivalent amplitude after the laser irradiates the first ion is less than a first threshold value; a second determination unit configured to obtain and set a first pulse duration of the laser, and to change a frequency difference between two laser beams split by the laser through a beam splitter, so as to determine a first probability that the first ion is in an excited state at each frequency difference; a third determining unit, configured to determine an eigenphonon frequency based on a change in the first probability as the frequency difference changes; The execution unit is configured to perform the following operations N times, where N is a positive integer greater than or equal to 2: adjusting the power value of the laser, and determining the equivalent amplitude after the laser irradiates the first ion at the current power value; Acquire and set a second pulse duration of the laser, and change a frequency difference between two laser beams split by the laser through a beam splitter to determine a second probability that the first ion is in an excited state at each frequency difference; determining a first phonon frequency based on a change in the second probability as a function of the frequency difference; determining a difference between the first phonon frequency and the intrinsic phonon frequency; and a correction unit configured to perform function fitting based on the corresponding relationship between the equivalent amplitude and the corresponding difference, so as to correct the phonon frequency under the corresponding equivalent amplitude based on the fitted function.

11. The device of claim 10, wherein: The acquisition unit includes an adjustment subunit configured to: adjust the power value of the laser until the determined equivalent amplitude is less than a first threshold value and determine the power value corresponding to when the equivalent amplitude is less than the first threshold value as an initial power value: Determine a frequency difference between the |g> state and the |e> state of the first ion, and determine a frequency difference between two laser beams split by the laser through a beam splitter based on the frequency difference; adjusting a pulse duration of the laser and determining a probability that the first ion is in an excited state after the first ion is irradiated by the laser at each pulse duration; Determining a third pulse duration corresponding to a probability that the first ion is in an excited state close to 1; as well as An equivalent amplitude after the laser irradiates the first ions is determined based on the third pulse duration.

12. The device of claim 10, wherein: The first pulse duration is greater than the second pulse duration.

13. The device of claim 10, wherein: The first threshold is 0.01 MHz.

14. The device of claim 10, wherein: The first determination unit includes a determination subunit configured to: change the incident angle of the laser within a first preset range according to a first preset step length to determine the position of the first ion through fluorescence imaging.

15. The apparatus according to claim 10, further comprising a fourth determining unit configured to: determining a Hamiltonian expression of a quantum system corresponding to the first ion, so as to determine, based on the Hamiltonian expression, respective probabilities that the first ion is in an excited state, in, The Hamiltonian expression includes a term corresponding to a blue sideband transition, a term corresponding to a red sideband transition, and a term corresponding to a main transition.

16. The device of claim 11, wherein: The equivalent amplitude Ω after the laser irradiates the first ion is determined based on the following formula: Ω=π / 2τ Wherein, τ is the duration of the third pulse.

17. An electronic device comprising: at least one processor; as well as a memory communicatively coupled to the at least one processor; in The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 9.

18. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-9.

19. A computer program product comprising a computer program, wherein: When the computer program is executed by a processor, the method according to any one of claims 1 to 9 is implemented.

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