Biological quantum computing device based on quadrupole ion nuclear spinning on phospholipid membrane

Abstract

The invention discloses a biological quantum computing device based on quadrupole ion nuclear spinning on a phospholipid membrane. The biological quantum computing device comprises a substrate; the phospholipid bilayer membrane is arranged on the substrate and is doped with ions of which the nuclear spin is greater than or equal to 1; the nanowire array is arranged on the other surface of the substrate; and the control element is arranged on the nanowire array. The nuclear spin in the phospholipid membrane is used as a quantum bit, and the quantum bit is controlled by controlling the electric field gradient, so that the quantum calculation function is realized. The method is a brand new quantum information processing mode, combines a silicon-based electronic process and a complex biomolecular system, carries out information processing through precise nuclear spin control, has an obvious advantage of small size, simplifies an external control system and a preparation process, reduces energy consumption and cost, and is convenient for integration and large-scale manufacturing.

Description

Technical Field

[0001] The present invention relates to the field of quantum computing technology, and in particular to a method for orienting nuclear spins using quadrupole ion nuclear spins (nuclear spins of ions whose nuclear quadrupole moment is not 0) on a phospholipid membrane and a device for performing quantum computing using the method. Background Art

[0002] Quantum computing is a new computing model that uses the principles of quantum mechanics to process information. This technology performs computing tasks by manipulating and measuring quantum states, and has potential computing advantages in solving specific complex problems. The superposition state characteristics of quantum computing enable it to exhibit performance far superior to that of classical computers, and it has a wide range of potential applications in cryptography, molecular simulation, optimization problems and other fields. Another important feature of quantum computing is quantum entanglement, which allows non-local correlations to form between multiple quantum bits. This correlation enables quantum computers to process large amounts of information at the same time, providing new possibilities for parallel computing. In addition, the quantum tunneling effect is also used in certain quantum algorithms, such as the quantum annealing algorithm, to solve complex optimization problems. In recent years, substantial progress has been made in quantum computing research, including the realization of quantum computing prototypes and experimental verification of quantum superiority.

[0003] Traditional quantum computing systems still face many challenges. Major quantum computing schemes, including superconducting quantum bits and ion trap systems, usually require extremely low temperature environments (close to absolute zero) to ensure quantum coherence. At the same time, they require sophisticated and complex control equipment, which greatly limits their practical application process. The scalability of the system is also a major challenge. As the number of quantum bits increases, it becomes increasingly difficult to maintain the coherence of the entire system, and the difficulty of control and readout increases exponentially. In addition, many quantum computing schemes have poor compatibility with existing integrated circuit technology and are difficult to directly integrate into existing semiconductor processes, resulting in a larger system size, which is not conducive to miniaturization and large-scale production. These defects are not conducive to the development of quantum computing towards practical application.

[0004] In view of these limitations of traditional quantum computing systems, the research community is actively exploring new quantum computing schemes, such as quantum computing based on solid-state systems and topological quantum computing. Kane proposed an architecture for a solid-state quantum computer, which consists of silicon wafers doped with phosphorus atoms. The nuclear spin of the phosphorus atom serves as a storage qubit, and the unpaired electron spin of the phosphorus atom acts as a control qubit, which is coupled to the phosphorus nuclear spin qubit and the adjacent electron spin qubit. The quantum computer is controlled by externally applied magnetic and electric fields. By etching nanowires on the silicon surface to build circuit elements, the magnetic and electric fields can be locally varied on a scale of about 30 nanometers. These external fields move electrons around and control the overlap of the wave functions of electrons with nuclear spins and with neighboring electrons. In this way, they control the exchange of quantum information between the nuclear storage qubit and the electronic control qubit.

[0005] Quantum effects in biological systems are also receiving increasing attention. Some studies have shown that quantum coherence can be maintained for quite a long time in a biological system environment, and some biological processes may utilize quantum effects, such as energy transfer in photosynthesis and quantum sensing in bird navigation. These findings have inspired scientists to think about whether biomolecules or bio-inspired systems can be used to build new quantum computing platforms. This approach may work at room temperature and have the advantages of biological systems such as self-assembly and self-repair. Summary of the invention

[0006] The present invention aims to provide a quantum computing device based on the nuclear spins of quadrupole ions on phospholipid membranes based on the quantum computing architecture proposed by Kane, using the nuclear spins of ions with nuclear spins greater than or equal to 1 in the phospholipid membranes as quantum bits, and controlling the quantum bits by controlling the electric field gradient, thereby realizing quantum computing functions, in order to solve the problems existing in existing quantum computing technologies, such as harsh working environment, complex system, and poor scalability.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] A biological quantum computing device based on the nuclear spin of quadrupole ions on a phospholipid membrane comprises: a substrate; a phospholipid bilayer membrane disposed on the substrate, wherein the membrane is doped with ions having a nuclear spin greater than or equal to 1; a nanowire array disposed on the other side of the substrate; and a control element disposed on the nanowire array.

[0009] In the biological quantum computing device based on quadrupole ion nuclear spin on phospholipid membrane:

[0010] The substrate can be a substrate such as silicon oxide, high-resistance silicon, or aluminum oxide, serving as a support structure to provide a flat and stable surface;

[0011] The phospholipid bilayer membrane is arranged on the substrate, and is a bilayer structure formed by self-assembly of phospholipid molecules. The various phospholipid molecules constituting the phospholipid bilayer membrane include, but are not limited to, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), etc., and their proportions can be changed at will;

[0012] The ions with nuclear spin greater than or equal to 1, such as sodium ions, copper ions, manganese ions, etc., are injected into the phospholipid bilayer membrane, and form coordination bonds with phospholipid molecules to be fixed in the membrane structure; these ion nuclear spins are oriented to a direction perpendicular to the membrane by the anisotropic motion of the phospholipid molecules, providing a reference for the membrane normal direction for the direction of the phosphorus nuclear spin and the proton nuclear spin used for quantum information storage;

[0013] The nanowire array is located on the other side of the substrate and is used to construct a control element, and can be composed of materials such as silicon, metal or semiconductor;

[0014] The control element is used to adjust the local electric field and / or magnetic field to achieve the control of a single phosphorus nuclear spin, a proton nuclear spin and an ion nuclear spin, and then perform quantum computing. Taking a microelectrode as an example, it is arranged on the nanowire array, and its functions include controlling the direction of a single phosphorus nuclear spin or a proton nuclear spin (for example, a metal electrode A gate is arranged near a phosphorus atom, and by adjusting the voltage on the A gate, the wave function of the electrons around the phosphorus nucleus can be affected, thereby affecting the coupling of the electron spin and the phosphorus nuclear spin, thereby controlling a single phosphorus nuclear spin), or regulating the interaction between adjacent spins (for example, a metal electrode J gate is arranged between two adjacent phosphorus atoms, and by adjusting the voltage on the J gate, the size of the electron cloud overlap between the two atoms can be affected, thereby controlling the coupling between the two nuclear spins).

[0015] The rotational motion of the phospholipid molecules in the phospholipid bilayer membrane around the membrane normal direction and the diffusion motion within the membrane plane generate a time-averaged electric field gradient in the coordinated ion nucleus. The direction of the maximum component of the electric field gradient is consistent with the normal direction of the phospholipid bilayer membrane, which is used to orient the nuclear spin of the ion so that the direction of the nuclear spin of the ion is consistent with the normal direction of the phospholipid bilayer membrane.

[0016] In a specific implementation, the phospholipid bilayer membrane can be sandwiched between two substrates, and nanowire arrays are respectively arranged on the other sides of the two substrates. Alternatively, only one substrate is used, a phospholipid bilayer membrane is formed on one side of the substrate, and a nanowire array is arranged on the other side. In one embodiment of the present invention, a group of parallel nanowires are respectively arranged on the upper and lower substrates, and the two groups of nanowires are perpendicular to each other in plane projection, forming an orthogonal control grid.

[0017] Preferably, micro-electrodes are arranged on the nanowire array to generate a local magnetic field to control the state of a single phosphorus nuclear spin or a proton nuclear spin.

[0018] Preferably, oxygen free radicals are generated by electrolyzing water or other oxygen-containing compounds by applying appropriate voltage through microelectrodes, thereby injecting oxygen free radicals with unpaired electrons into the phospholipid bilayer membrane, and controlling the voltage of the microelectrodes to control the concentration and distribution of the generated oxygen free radicals. The two unpaired electrons of an oxygen free radical interact with the two proton nuclear spins respectively, which can entangle the two nuclear spins with each other and regulate the coupling between the two nuclear spins.

[0019] The present invention also provides a method for preparing the above-mentioned biological quantum computing device, comprising the following steps:

[0020] 1) Preparing a nanowire array on a substrate (such as a silicon wafer) by deposition and etching;

[0021] 2) forming a phospholipid bilayer membrane on the other side of the substrate;

[0022] 3) Injecting ions with a nuclear spin greater than or equal to 1 into the phospholipid bilayer membrane so that the ions form coordination bonds with the phospholipid molecules.

[0023] The present invention further provides a method for performing quantum computing using the above-mentioned biological quantum computing device, comprising:

[0024] The time-averaged electric field gradient generated by the rotational motion of the phospholipid molecules around the normal line of the phospholipid bilayer membrane and the diffusion motion in the plane of the phospholipid bilayer membrane is used to direct the ion nuclear spin to the normal line direction of the phospholipid bilayer membrane, initialize the ion nuclear spin, and the directed ion nuclear spin transmits the direction information to the phosphorus nuclear spin and proton nuclear spin by interacting with the surrounding phosphorus nuclear spin and proton nuclear spin;

[0025] By manipulating the control elements on the nanowire array, the coupling strength between the nuclear spins is adjusted; the specific methods include but are not limited to: adjusting the concentration and distribution of oxygen free radicals generated by electrolysis in the phospholipid bilayer membrane through the control elements, thereby adjusting the coupling strength between the nuclear spins; or, by applying a local electric field through the control elements such as electrodes, manipulating the head position of the charged phospholipid molecules at certain positions to rotate toward the direction of the electric field, so as to adjust the relative position of the charged phospholipid molecules and other phospholipid molecules, thereby changing the relative distance between the two phosphorus nuclear spins, thereby adjusting the coupling strength between the nuclear spins;

[0026] By measuring the nuclear magnetic resonance signal, the states of the phosphorus nuclear spin and the proton nuclear spin are read out, that is, the calculation results.

[0027] The beneficial effects of the present invention are:

[0028] 1. The electric field gradient spontaneously generated by the movement of phospholipid molecules simplifies the external control system;

[0029] 2. Utilizing the self-assembly characteristics of biomolecules, the preparation process of quantum computing systems is simplified;

[0030] 3. It can be integrated on silicon-based chips, facilitating large-scale manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The device structure and the above advantages and features of the present invention will become more clear through the following description in conjunction with the accompanying drawings.

[0032] Figure 1 It is a schematic diagram of the direction of the time-averaged electric field gradient generated by the movement of phospholipid molecules in the present invention.

[0033] Figure 2 It is a schematic diagram of the cross-sectional structure of a biological quantum computing device in an embodiment of the present invention.

[0034] Figure 3 It is a schematic diagram of the upper surface structure of the biological quantum computing device in an embodiment of the present invention.

[0035] Figure 4 It is a schematic diagram of the lower surface structure of the biological quantum computing device in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0037] Figure 2 The schematic diagram of the cross-sectional structure of a biological quantum computing device in one embodiment of the present invention is shown. The biological quantum computing device in this embodiment comprises a substrate 2, a phospholipid bilayer membrane 3 is stacked between two substrates 2, and ions 4 with nuclear spin greater than or equal to 1 are distributed in the phospholipid bilayer membrane 3; and a plurality of parallel upper nanowires 1 and lower nanowires 5 are respectively arranged on the other side of the two substrates 2.

[0038] 1. Substrate 2: serves as the basic support structure of the entire device. In a preferred embodiment, substrate 2 is made of high-resistance silicon material, and its resistivity is preferably above 10,000Ω·cm. The thickness of substrate 2 can be between 100μm and 1000μm, preferably 500μm. The surface of substrate 2 is precisely polished, and its surface roughness is controlled to be below 1nm to ensure the uniformity and stability of the subsequent structure.

[0039] 2. Upper nanowires 1 and lower nanowires 5: multiple parallel nanowires arranged on the surface of substrate 2. These nanowires can be made of metal materials (such as gold, silver, platinum, etc.) or doped semiconductor materials. The material and size of the upper nanowires 1 can be the same as those of the lower nanowires 5, or can be adjusted as needed. The upper nanowires 1 and the lower nanowires 5 are perpendicular to each other in plane projection, forming an orthogonal control grid. In this embodiment, the upper nanowires 1 and the lower nanowires 5 are made of gold material, with a width between 50nm and 200nm and a height between 20nm and 100nm. The spacing between adjacent nanowires can be adjusted between 100nm and 1μm. These nanowires are used to form control elements to regulate the state of phosphorus nuclear spins or proton nuclear spins.

[0040] 3. Phospholipid bilayer membrane 3: a biological membrane structure sandwiched between two substrates 2. The phospholipid bilayer membrane 3 can be composed of a variety of phospholipid molecules, such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), etc. The thickness of the phospholipid bilayer membrane 3 is usually between 4nm and 6nm, preferably 5nm. The membrane structure provides a medium similar to the biological environment for accommodating and directional distribution of ions with nuclear spin greater than or equal to 1 (preferably sodium ions).

[0041] 4. Ions 4 with nuclear spin greater than or equal to 1: functional ions distributed in the phospholipid bilayer membrane 3. These ions form coordination bonds with the phospholipid molecules of the phospholipid bilayer membrane 3, and their concentration can be adjusted between 10mM and 100mM.

[0042] The nuclear spin of ion 4, as a directional quantum bit, is a key element in realizing quantum computing.

[0043] In some embodiments, the device may further include:

[0044] 5. Protective layer (not shown in the figure, optional): a thin layer covering the surface of the phospholipid bilayer membrane 3. It can be made of a hydrophilic polymer such as polyethylene glycol (PEG) with a thickness between 1nm and 10nm. The protective layer can increase the stability of the phospholipid membrane and extend the service life of the device.

[0045] Figure 1 The schematic diagram of the time-averaged electric field gradient direction generated by the motion of phospholipid molecules in the present invention is shown, and the three main axis components of the time-averaged electric field gradient are and Based on the principle of nuclear electric resonance, electric field gradient (EFG) can be used to control nuclear spins greater than 1 / 2. Inside the atom, the charge distribution of the nucleus is affected by the nuclear spin, forming a rotating ellipsoid along the direction of the nuclear spin. The deviation of the nucleus from the spherical shape produces a nuclear quadrupole moment, which interacts with the electric field generated by the electron, called the nuclear quadrupole interaction. Therefore, for nuclei with spins greater than 1 / 2 (and therefore with a non-zero electric quadrupole moment), the local EFG will interact with its electric quadrupole moment, causing these nuclear spins to produce energy level splitting. The size of the energy level gap is related to the value of EFG. Under EFG, the nuclear quadrupole moment precesses around the axis, and the nuclear spin also precesses around the axis. The direction of the axis depends on the EFG and generally tends to be aligned with the principal axis of the largest component of the EFG. direction of alignment.

[0046] The EFG of ionic 4 nuclei with nuclear spin greater than or equal to 1 in the phospholipid bilayer membrane 3 is affected by the distribution of valence electrons or bonds and electrons from nearby atoms. Differences in the surrounding electronic environment, including differences in coordination numbers and the shape of the coordination sphere, can cause changes in the EFG of the nucleus. The phospholipid molecules will move in the plane of the membrane, either rotating about the membrane normal (called the z-axis) or diffusing laterally in the plane of the membrane. Therefore, the direction of the coordination bonds between the ionic 4 nuclei and the phospholipid molecules also changes in an anisotropic manner.

[0047] On longer time scales, the EFG of the ion 4 position coordinated to the phospholipid molecules undergoes rapid fluctuations in the tangential components due to the rapid rotational and diffusional motion of the phospholipid molecules in the membrane plane, resulting in the cancellation of the time-averaged EFG of these tangential components. In contrast, in the normal direction perpendicular to the plane, the phospholipid molecules have fewer dynamics and present a relatively more consistent and obvious EFG. This different behavior leads to an anisotropic equivalent EFG, which has a smaller component in the tangential direction of the membrane and a more obvious component in the normal direction. The unification of the axial direction of the EFG will provide a unified quantization axis for the nuclear spins of sodium ions on the phospholipid membrane.

[0048] Figure 3 The schematic diagram of the upper surface structure of the biological quantum computing device in the embodiment of the present invention is shown. On the upper surface of the device, there are multiple upper nanowires 1 arranged in parallel. These nanowires are used to form a high-density control element array to generate local electric or magnetic fields to regulate the process of quantum computing. The number of nanowires depends on the required control accuracy and the overall size of the device.

[0049] Figure 4The schematic diagram of the lower surface structure of the biological quantum computing device in the embodiment of the present invention is shown. On the lower surface of the device, there are also multiple lower layer nanowires 5 arranged in parallel, which generate local electric fields or magnetic fields to regulate the process of quantum computing. These nanowires 5 are perpendicular to the nanowires 1 on the upper surface in space, and the nanowires on the two surfaces together form a set of two-dimensional control grids.

[0050] The present invention proposes a new quantum information processing method, combining silicon-based electronic technology and complex biomolecular systems, and performing information processing through precise nuclear spin control. The present invention uses phospholipid membranes and ions with nuclear spin greater than or equal to 1 as the material basis of nuclear spin, and has obvious advantages of small size, which means higher integration and smaller device size. In terms of computing speed and capacity, the present invention uses nuclear spins on phospholipid membranes as quantum bits for calculation, with a large number of quantum bits, similar to the physical architecture of modern computers. In addition, ions with nuclear spin greater than or equal to 1, such as phospholipid membranes and sodium ions, are relatively common and low in cost. The present invention uses an electric field gradient to control the direction of the quantization axis of the system without the need for an external magnetic field, which simplifies experimental equipment and operations, while reducing energy consumption and costs.

[0051] While the present application has been shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that various modifications and variations may be made to these embodiments without departing from the spirit and scope of the present application as defined by the appended claims.

Claims

1. A biological quantum computing device based on quadrupole ion nuclear spin on a phospholipid membrane, comprising: substrate; A phospholipid bilayer membrane disposed on the substrate, wherein the membrane is doped with ions having a nuclear spin greater than or equal to 1; A nanowire array disposed on the other side of the substrate; A control element is disposed on the nanowire array.

2. The biological quantum computing device according to claim 1, characterized in that: The phospholipid bilayer membrane is a bilayer structure formed by self-assembly of phospholipid molecules on the substrate, wherein the doped ions with nuclear spin greater than or equal to 1 form coordination bonds with the phospholipid molecules and are fixed in the membrane structure, and these ion nuclear spins are oriented to a direction perpendicular to the membrane by the anisotropic motion of the phospholipid molecules.

3. The biological quantum computing device according to claim 2, characterized in that: The phospholipid molecules are selected from phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine; and the ions with nuclear spin greater than or equal to 1 are selected from sodium ions, copper ions, and manganese ions.

4. The biological quantum computing device according to claim 1, characterized in that: The substrate is a silicon oxide, high-resistance silicon or aluminum oxide substrate; the nanowire array is composed of silicon, metal or semiconductor material.

5. The biological quantum computing device according to claim 1, characterized in that: The control element is a microelectrode.

6. The biological quantum computing device according to claim 1, characterized in that: The biological quantum computing device includes two substrates, the phospholipid bilayer membrane is sandwiched between the two substrates, and nanowire arrays are respectively arranged on the other sides of the two substrates; or, the biological quantum computing device includes a substrate, a phospholipid bilayer membrane is formed on one side of the substrate, and a nanowire array is arranged on the other side.

7. The biological quantum computing device according to claim 6, characterized in that: The biological quantum computing device includes two upper and lower substrates. A group of parallel nanowires are respectively arranged on the upper surface of the upper substrate and the lower surface of the lower substrate. The two groups of nanowires are perpendicular to each other in plane projection to form an orthogonal control grid.

8. A method for preparing the biological quantum computing device according to any one of claims 1 to 7, comprising the following steps: 1) Preparing a nanowire array on a substrate by deposition and etching; 2) forming a phospholipid bilayer membrane on the other side of the substrate; 3) Injecting ions with a nuclear spin greater than or equal to 1 into the phospholipid bilayer membrane so that the ions form coordination bonds with the phospholipid molecules.

9. A method for performing quantum computing using the biological quantum computing device according to any one of claims 1 to 7, comprising: The time-averaged electric field gradient generated by the rotational motion of the phospholipid molecules around the normal line of the phospholipid bilayer membrane and the diffusion motion in the plane of the phospholipid bilayer membrane is used to direct the ion nuclear spin to the normal line direction of the phospholipid bilayer membrane, initialize the ion nuclear spin, and the directed ion nuclear spin transmits the direction information to the phosphorus nuclear spin and proton nuclear spin by interacting with the surrounding phosphorus nuclear spin and proton nuclear spin; The coupling strength between nuclear spins is adjusted by manipulating the control element; By measuring the nuclear magnetic resonance signal, the states of the phosphorus nuclear spin and the proton nuclear spin are read out to obtain the calculation results.

10. The method according to claim 9, characterized in that The control element is used to adjust the concentration and distribution of oxygen free radicals generated by electrolysis in the phospholipid bilayer membrane, thereby adjusting the coupling strength between nuclear spins; or, the control element is used to apply a local electric field to manipulate the head position of charged phospholipid molecules at certain positions to rotate toward the direction of the electric field to adjust the relative position of the charged phospholipid molecule and other phospholipid molecules, thereby changing the relative distance between the two phosphorus nuclear spins, thereby adjusting the coupling strength between nuclear spins.

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