Coherent state-based weak measurement sensing method, device and system

Abstract

The invention discloses a weak measurement sensing method, device and system based on a coherent state. Local oscillation light and coherent state signal light are obtained. And inputting the signal light into the weak measurement unit by taking a coherent state as a pointer state based on a to-be-measured signal to obtain a quantum state of the signal light. The carriers selected by the weak measurement system are enriched, and the application range of the weak measurement technology is expanded. Heterodyne detection is carried out on a quantum state by using local oscillation light, and secondary amplification is carried out on a signal to obtain a detection result, so that high-sensitivity sensing on a tiny signal is realized. And acquiring the variation of the to-be-detected signal based on the detection result, and calculating to obtain a detection signal according to the variation. According to the invention, high-sensitivity detection is carried out on tiny physical quantities by adopting quantum resources, the application of a quantum sensing technology on the premise of high measurement precision is supported, and the advantages of the quantum resources are fully exerted.

Description

Technical Field

[0001] The present application relates to the field of quantum sensing technology, and in particular to a method, device and system for weak measurement sensing based on coherent states. Background Art

[0002] Quantum sensing is the process of measuring the physical quantities of objects using quantum resources. It can surpass the measurement accuracy and sensitivity of traditional measurement techniques, and therefore performs very well in the fields of gravitational wave detection, inertial navigation systems, magnetometers, etc.

[0003] In the prior art, weak value amplification technology can improve measurement accuracy by setting a post-selection state that is almost perpendicular to the pre-selection state. However, the measurement signal in this method, that is, the measurement intensity, will be relatively weak. When weak value amplification technology is applied to quantum sensing, the measurement signal is difficult to detect, resulting in the inability to achieve accurate measurement. Therefore, how to use quantum sensing technology under the premise of high measurement accuracy has become an urgent problem to be solved. Summary of the invention

[0004] Based on the above problems, the present application provides a method, device and system for weak measurement sensing based on coherent states, so as to utilize quantum sensing technology with high measurement accuracy.

[0005] The present application discloses a method for weak measurement sensing based on coherent states, the method comprising:

[0006] Acquire local oscillator light and signal light; the signal light is in a coherent state;

[0007] Based on the signal to be measured, the signal light is input into a weak measurement unit to obtain the quantum state of the signal light;

[0008] Using the local oscillator light to perform heterodyne detection on the quantum state to obtain a detection result;

[0009] The change amount of the signal to be detected is acquired based on the detection result, and the detection signal is obtained by calculation according to the change amount.

[0010] Optionally, inputting the signal light into a weak measurement unit based on the signal to be measured to obtain the quantum state of the signal light includes:

[0011] modulating the coherent state of the signal light into a pre-selected state;

[0012] Introducing the signal to be measured to cause weak coupling between the signal light and the weak measurement unit;

[0013] The signal light after weak coupling is projected onto a post-selection state approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset.

[0014] Optionally, the using the local oscillator light to perform heterodyne detection on the quantum state includes:

[0015] combining the local oscillator light with the quantum state to form beat frequency light;

[0016] After the beat frequency light is detected by a detector, it is input into a differential circuit to obtain the detection result.

[0017] Optionally, combining the local oscillator light with the quantum state to form beat frequency light includes:

[0018] Evenly dividing the quantum state into a first quantum state and a second quantum state;

[0019] The local oscillation light is evenly divided into a first local oscillation light and a second local oscillation light; the phase of the first local oscillation light is a first phase, and the phase of the second local oscillation light is a second phase;

[0020] The first path of local oscillator light is combined with the first path of quantum state to form a first beat frequency light, and the second path of local oscillator light is combined with the second path of quantum state to form a second beat frequency light.

[0021] Optionally, the first detection result is obtained by the first beat frequency light, the second detection result is obtained by the second beat frequency light, and the changing amount of the signal to be measured is obtained based on the detection result, and the detection signal is obtained by calculation according to the changing amount, including:

[0022] Calculating a sum of squares of the first detection result and the second detection result;

[0023] When a weak measurement condition is met, an approximate value of the sum of squares is obtained; the weak measurement condition is that the phase parameter corresponding to the signal to be measured is much smaller than the post-selection angle;

[0024] Obtaining a change amount of the signal to be measured according to the approximate value;

[0025] The signal to be tested is restored according to the change amount to obtain the detection signal.

[0026] Based on the above-mentioned method of weak measurement sensing based on coherent state, the present application also discloses a device of weak measurement sensing based on coherent state, including: an acquisition module, an input module, a detection module and a recovery module;

[0027] The acquisition module is used to acquire local oscillator light and signal light; the signal light is in a coherent state;

[0028] The input module is used to input the signal light into the weak measurement unit based on the signal to be measured to obtain the quantum state of the signal light;

[0029] The detection module is used to perform heterodyne detection on the quantum state using the local oscillator light to obtain a detection result;

[0030] The recovery module is used to obtain the change amount of the signal to be detected based on the detection result, and calculate the detection signal according to the change amount.

[0031] Optionally, the input module includes:

[0032] A pre-selection submodule, used for modulating the coherent state of the signal light into a pre-selection state;

[0033] A weak coupling submodule, used for introducing the signal to be measured to cause weak coupling between the signal light and the weak measurement unit;

[0034] The post-selection submodule is used to project the signal light after weak coupling to a post-selection state that is approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset.

[0035] Optionally, the detection module includes:

[0036] A beat frequency submodule, used for combining the local oscillation light with the quantum state to form a beat frequency light;

[0037] The differential submodule is used to input the beat frequency light into a differential circuit after being detected by a detector to obtain the detection result.

[0038] Optionally, the beat frequency submodule includes:

[0039] A photon splitting module, used for evenly dividing the quantum state into a first quantum state and a second quantum state;

[0040] A submodule is provided, which is used to evenly divide the local oscillation light into a first local oscillation light and a second local oscillation light; the phase of the first local oscillation light is a first phase, and the phase of the second local oscillation light is a second phase;

[0041] The combining submodule is used to combine the first local oscillator light with the first quantum state to form a first beat frequency light, and to combine the second local oscillator light with the second quantum state to form a second beat frequency light.

[0042] Optionally, the first detection result is obtained by the first beat frequency light, the second detection result is obtained by the second beat frequency light, and the recovery module includes:

[0043] A summing submodule, used for calculating the square sum of the first detection result and the second detection result;

[0044] An approximation submodule, used for obtaining an approximate value of the sum of squares when a weak measurement condition is met; the weak measurement condition is that the phase parameter corresponding to the signal to be measured is much smaller than the post-selection angle;

[0045] A calculation submodule, used for obtaining a change amount of the signal to be measured according to the approximate value;

[0046] The recovery submodule is used to recover the signal to be tested according to the change amount to obtain the detection signal.

[0047] Based on the above-mentioned method of weak measurement sensing based on coherent states, the present application also discloses a system of weak measurement sensing based on coherent states, which is used to implement the above-mentioned method, and the system includes:

[0048] A light source, used for generating local oscillator light and coherent state signal light;

[0049] A weak measurement unit, used for receiving a signal to be measured and the signal light, and outputting a quantum state of the signal light;

[0050] The processing unit is used to split and calculate the optical signal to obtain the detection signal.

[0051] Optionally, the light source includes a coherent state light source and a local oscillation light source, the coherent state light source generates the signal light, and the local oscillation light source generates the local oscillation light.

[0052] Optionally, the weak measurement unit consists of a front selection subunit, a weak coupling subunit and a rear selection subunit.

[0053] Optionally, the processing unit consists of a beam splitter, a phase shifter, a detector and a differential circuit.

[0054] The present application discloses a method, device and system for weak measurement sensing based on coherent states. According to obtaining local oscillator light and coherent state signal light. Based on the signal to be measured, the coherent state is used as the pointer state, the signal light is input into the weak measurement unit, and the quantum state of the signal light is obtained. The carriers selected by the weak measurement system are enriched, and the application scope of the weak measurement technology is expanded. The quantum state is heterodyne detected using the local oscillator light, and the signal is amplified twice to obtain the detection result, thereby realizing high-sensitivity perception of tiny signals. Based on the detection result, the change amount of the signal to be measured is obtained, and the detection signal is calculated according to the change amount. The present application uses quantum resources to perform high-sensitivity detection of tiny physical quantities, supports the application of quantum sensing technology under the premise of high measurement accuracy, and ensures that the advantages of quantum resources are fully utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0056] Figure 1 A schematic flow chart of a method for weak measurement sensing based on coherent states disclosed in an embodiment of the present application;

[0057] Figure 2 A schematic flow chart of another method for weak measurement sensing based on coherent states disclosed in an embodiment of the present application;

[0058] Figure 3 A schematic diagram of the structure of a device for weak measurement sensing based on coherent states disclosed in an embodiment of the present application;

[0059] Figure 4 This is a schematic diagram of the structure of a system for weak measurement sensing based on coherent states disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] Embodiment 1: This application discloses a method of weak measurement sensing based on coherent states.

[0062] For details, please refer to Figure 1 , a method for weak measurement sensing based on coherent states disclosed in this embodiment includes the following steps:

[0063] Step 101: Obtain local oscillator light and signal light.

[0064] In the method described in this embodiment, the signal light source and the local oscillator light source can be prepared by using a seed light source. The signal light emitted by the signal light source is a coherent state, which can be expressed as |α>=|x+ip>, where x and p are the regular components of the coherent state. The local oscillator light emitted by the local oscillator light source can be expressed as |a Lo |e iθ , where i is the imaginary unit, |α Lo | is the amplitude of the local oscillator light source, and θ is the phase of the local oscillator light source.

[0065] In the method described in this embodiment, both the local oscillator light and the signal light are optical signals, and the canonical component of the coherent state refers to two basic variables of the coherent state in the phase space: the canonical position component and the canonical momentum component. The phase space is an abstract space used to describe the state of a quantum system, with the horizontal axis representing the canonical position component and the vertical axis representing the canonical momentum component.

[0066] Step 102: Based on the signal to be measured, the signal light is input into a weak measurement unit to obtain the quantum state of the signal light.

[0067] In the method described in this embodiment, as an optional method, the weak measurement unit can be composed of some optical devices, and the light passing through these optical devices is said to pass through the weak measurement unit. After the weak measurement unit is built, the signal light can be input into the weak measurement unit.

[0068] In the method described in this embodiment, when the signal light passes through the pre-selection state subunit in the weak measurement unit, the coherent state of the signal light is modulated to the pre-selection state. As an optional method, the coherent state of the signal light can be expressed as |Ψ0>=|i>|α>, where the expression of the pre-selection state is as follows:

[0069]

[0070] Where |H> is the horizontal polarization state and |V> is the vertical polarization state.

[0071] In the method described in this embodiment, the signal to be measured is introduced into the weak coupling subunit in the weak measurement unit. The signal to be measured can be understood as a signal to be sensed, such as an acoustic signal, a temperature signal, a voltage, etc. In the weak coupling subunit, the signal to be measured causes weak coupling between the signal light and the weak measurement unit. That is, the composite system composed of the quantum system and the weak measurement unit begins to evolve over time, and this evolution process usually follows the basic laws of quantum mechanics such as the Schrödinger equation.

[0072] As an alternative method, the signal to be measured is first encoded as a time-varying phase parameter The weakly coupled process can be expressed as follows:

[0073]

[0074] Where e is the natural index and Stokes parameter

[0075] The signal after weak coupling can be expressed as

[0076] In the method described in this embodiment, the signal after weak coupling, that is, |Ψ(t)>, is sent to the post-selection subunit in the weak measurement unit. In this subunit, the signal after weak coupling is projected to a post-selection state that is approximately orthogonal to the pre-selection state, thereby obtaining the quantum state of the signal light passing through the complete weak measurement unit. Through post-selection, a parameter similar to the amplification factor, namely the weak value, can be obtained. The weak value reflects the information of the signal to be measured and can realize the amplified observation of tiny physical quantities. Among them, the post-selection state can be pre-set when building the weak measurement unit according to actual needs, and can be expressed as follows:

[0077]

[0078] Where ε is the post-selection angle, which is usually much smaller than 1 in order to achieve the amplification effect.

[0079] The projected signal is the quantum state of the signal light. In simple terms, it is the signal obtained by changing the mathematical or physical form of the signal light. The quantum state can be expressed as follows:

[0080]

[0081] Step 103: Use the local oscillator light to perform heterodyne detection on the quantum state to obtain a detection result.

[0082] The basic principle of heterodyne detection is the coherence of two light waves. When receiving the signal light, the local oscillator light is added. The frequency of the local oscillator light is very close to the frequency of the signal light, so that the local oscillator light and the signal light form a beat signal on the photosensitive surface of the photodetector. The detector is then used to respond to the beat signal, thereby detecting the modulated signal in the signal light.

[0083] In the method described in this embodiment, the first local oscillator light can be set to a first phase of 0 through a phase shifter, and then combined with the quantum state of the first signal light in a beam splitter to form a first beat frequency light. The first beat frequency light includes a first sub-beat frequency light obtained through the transmission end of the beam splitter, and a second sub-beat frequency light obtained through the reflection end of the beam splitter. Therefore, the first sub-beat frequency light and the second sub-beat frequency light are different. They can be expressed as follows:

[0084]

[0085] After the first sub-beat frequency light and the second sub-beat frequency light are detected by the detector, they are input into the differential circuit to obtain the first detection result, which is expressed as |α Lo |x f (t).

[0086] Correspondingly, the second local oscillator light can be set to the second phase of half π by the phase shifter, and then combined with the quantum state of the second signal light in the beam splitter to form the second beat frequency light. The second beat frequency light includes the third sub-beat frequency light obtained through the transmission end of the beam splitter, and the fourth sub-beat frequency light obtained through the reflection end of the beam splitter. Therefore, the third sub-beat frequency light and the fourth sub-beat frequency light are also different. They can be expressed as follows:

[0087]

[0088] After the third sub-beat frequency light and the fourth sub-beat frequency light are detected by the detector and input into the differential circuit, the second detection result can be obtained, which is expressed as |α Lo |p f (t).

[0089] As an alternative method, the quantum state |Ψ f (t)> According to the definition of coherent state, write (x f (t)+ip f (t)), and then the quantum state is evenly divided into the first quantum state and the second quantum state. Correspondingly, the local oscillator light is also evenly divided into the first local oscillator light and the second local oscillator light.

[0090] As an optional method, the phase of the first local oscillator light is set to the first phase and the phase of the second local oscillator light is set to the second phase through a phase shifter. For example, the first phase can be 0, the second phase can be π / 2, and the sum of the two can be π / 2. The specific values ​​can be set according to actual needs and are not limited here.

[0091] Step 104: Obtain the change amount of the signal to be measured based on the detection result, and calculate the detection signal according to the change amount.

[0092] In the method described in this embodiment, the sum of the squares of the first detection result and the second detection result is calculated, that is, the sum of the squares of the two regular components is calculated, which can be expressed as the following formula:

[0093]

[0094] In the method described in this embodiment, when the weak measurement condition that the phase parameter corresponding to the measured signal is much smaller than the post-selection angle is met, the approximate value of the square sum is obtained as In weak coupling, the signal to be measured is encoded into a phase parameter. The change of the phase parameter has a linear relationship with the change of the detection signal. Therefore, the change of the signal to be measured can be calculated, which can be expressed as That is the recovered value of the phase. Then restore the signal to be tested according to the following formula to obtain the detection signal:

[0095]

[0096] The method described in this embodiment of the present application discloses a method, device and system for weak measurement sensing based on coherent states. The signal to be measured and the signal light are input into the weak measurement unit to obtain the quantum state of the signal light, thereby using quantum resources to perform high-precision and high-sensitivity detection of tiny physical quantities. At the same time, the quantum state is heterodyned using the local oscillator light, and the signal is amplified twice to obtain the detection result. Based on the detection result, the change in the signal to be measured is obtained, and the detection signal is calculated according to the change. High-sensitivity perception of tiny signals is achieved. Thereby enriching the carriers selected for the weak measurement system and expanding the application scope of weak measurement technology. This application supports the application of quantum sensing technology under the premise of high measurement accuracy to ensure that the advantages of quantum resources are fully utilized.

[0097] Embodiment 2: This application discloses another method of weak measurement sensing based on coherent state, please refer to Figure 2 , the method described in this embodiment introduces the whole process of acquiring the detection signal.

[0098] Step 201: inputting the coherent signal light and the signal to be measured into a weak measurement unit.

[0099] Step 202: The weak measurement unit outputs the quantum state of the signal light.

[0100] Step 203: splitting the local oscillator light and the quantum state respectively to obtain a first path of local oscillator light, a second path of local oscillator light, a first path of quantum state and a second path of quantum state.

[0101] Step 204: combining the first path of local oscillation light with the first path of quantum state to obtain a first beat frequency light, which includes a first sub-beat frequency light and a second sub-beat frequency light.

[0102] Step 205: combining the second path of local oscillation light with the second path of quantum state to obtain a second beat frequency light, which includes a third sub-beat frequency light and a fourth sub-beat frequency light.

[0103] Step 206: input the first sub-beat frequency light and the second sub-beat frequency light into the detector and the differential circuit to obtain a first detection result.

[0104] Step 207: input the third sub-beat frequency light and the fourth sub-beat frequency light into the detector and the differential circuit to obtain a second detection result.

[0105] Step 208: Calculate the square sum of the first detection result and the second detection result.

[0106] Step 209: Determine whether the phase parameter is much smaller than the post-selection angle. If yes, proceed to step 210. If no, adjust the weak measurement unit.

[0107] Step 210: Obtain an approximate value of the sum of squares, and calculate the change of the signal to be measured based on it.

[0108] Step 211: restore the signal to be tested according to the change amount to obtain a detection signal.

[0109] Based on the method of weak measurement sensing based on coherent state disclosed in the above embodiment, this embodiment correspondingly discloses a device for weak measurement sensing based on coherent state. Figure 3 , the device based on coherent state weak measurement sensing includes: an acquisition module 301, an input module 302, a detection module 303 and a recovery module 304;

[0110] The acquisition module 301 is used to acquire local oscillator light and signal light; the signal light is in a coherent state;

[0111] The input module 302 is used to input the signal light into the weak measurement unit based on the signal to be measured to obtain the quantum state of the signal light;

[0112] The detection module 303 is used to perform heterodyne detection on the quantum state using the local oscillator light to obtain a detection result;

[0113] The recovery module 304 is used to obtain the change amount of the signal to be detected based on the detection result, and calculate the detection signal according to the change amount.

[0114] Optionally, the input module 302 includes:

[0115] A pre-selection submodule, used for modulating the coherent state of the signal light into a pre-selection state;

[0116] A weak coupling submodule, used for introducing the signal to be measured to cause weak coupling between the signal light and the weak measurement unit;

[0117] The post-selection submodule is used to project the signal light after weak coupling to a post-selection state that is approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset.

[0118] Optionally, the detection module 303 includes:

[0119] A beat frequency submodule, used for combining the local oscillation light with the quantum state to form a beat frequency light;

[0120] The differential submodule is used to input the beat frequency light into a differential circuit after being detected by a detector to obtain the detection result.

[0121] Optionally, the beat frequency submodule includes:

[0122] A photon splitting module, used for evenly dividing the quantum state into a first quantum state and a second quantum state;

[0123] A submodule is provided, which is used to evenly divide the local oscillation light into a first local oscillation light and a second local oscillation light; the phase of the first local oscillation light is a first phase, and the phase of the second local oscillation light is a second phase;

[0124] The combining submodule is used to combine the first local oscillator light with the first quantum state to form a first beat frequency light, and to combine the second local oscillator light with the second quantum state to form a second beat frequency light.

[0125] Optionally, the first detection result is obtained by the first beat frequency light, and the second detection result is obtained by the second beat frequency light, and the recovery module 304 includes:

[0126] A summing submodule, used for calculating the square sum of the first detection result and the second detection result;

[0127] An approximation submodule, used for obtaining an approximate value of the sum of squares when a weak measurement condition is met; the weak measurement condition is that the phase parameter corresponding to the signal to be measured is much smaller than the post-selection angle;

[0128] A calculation submodule, used for obtaining a change amount of the signal to be measured according to the approximate value;

[0129] The recovery submodule is used to recover the signal to be tested according to the change amount to obtain the detection signal.

[0130] Based on the method of weak measurement sensing based on coherent state disclosed in the above embodiment, this embodiment correspondingly discloses a system of weak measurement sensing based on coherent state, which is used to implement the above method. The system of weak measurement sensing based on coherent state includes:

[0131] A light source, used for generating local oscillator light and coherent state signal light;

[0132] A weak measurement unit, used for receiving a signal to be measured and the signal light, and outputting a quantum state of the signal light;

[0133] The processing unit is used to split and calculate the optical signal to obtain the detection signal.

[0134] In the system described in this embodiment, Figure 4 This is a schematic diagram of the structure of a system based on weak measurement sensing of coherent states disclosed in an embodiment of the present application. Figure 4 The light source includes a coherent light source 1 and a local oscillation light source 5. The coherent light source 1 generates signal light, and the local oscillation light source 5 generates local oscillation light. A signal source 18 to be measured is also included, which is used to generate a signal to be measured.

[0135] In the system described in this embodiment, the weak measurement unit is composed of a front selection subunit 2, a weak coupling subunit 3 and a rear selection subunit 4. The processing unit is composed of a beam splitter, a phase shifter, a detector and a differential circuit.

[0136] Specifically, the quantum state output by the post-selector unit 4 is split by the beam splitter 7, and the local oscillator light is also split by the beam splitter 6. The first path of local oscillator light passes through the phase shifter 8 and is input to the beam splitter 9 together with the first path of quantum state. The second path of local oscillator light passes through the phase shifter 13 and is input to the beam splitter 14 together with the second path of quantum state.

[0137] The beam splitter 9 outputs the first sub-beat frequency light to the detector 10, and the second sub-beat frequency light to the detector 11. The detectors 10 and 11 output optical signals to the differential circuit 12. The beam splitter 14 outputs the third sub-beat frequency light to the detector 15, and the fourth sub-beat frequency light to the detector 16. The detectors 15 and 16 output optical signals to the differential circuit 17. Finally, the differential circuit 12 outputs the first detection result, and the differential circuit 17 outputs the second detection result, and subsequent calculations and other processing are performed.

[0138] The embodiments in this specification are described in a progressive manner. As for the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the methods.

[0139] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0140] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0141] The features described in the embodiments of this specification can be replaced or combined with each other, so that professional and technical personnel in this field can implement or use the present application.

[0142] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of weak measurement sensing based on coherent states, characterized in that: include: Obtaining local oscillator light and signal light; The signal light is in a coherent state; Based on the signal to be measured, the signal light is input into a weak measurement unit to obtain the quantum state of the signal light; Using the local oscillator light to perform heterodyne detection on the quantum state to obtain a detection result; The change amount of the signal to be detected is acquired based on the detection result, and the detection signal is obtained by calculation according to the change amount.

2. The method according to claim 1, characterized in that The step of inputting the signal light into a weak measurement unit based on the signal to be measured to obtain the quantum state of the signal light comprises: modulating the coherent state of the signal light into a pre-selected state; Introducing the signal to be measured to cause weak coupling between the signal light and the weak measurement unit; The signal light after weak coupling is projected onto a post-selection state approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset.

3. The method according to claim 2, characterized in that The using the local oscillator light to perform heterodyne detection on the quantum state comprises: combining the local oscillator light with the quantum state to form beat frequency light; After the beat frequency light is detected by a detector, it is input into a differential circuit to obtain the detection result.

4. The method according to claim 3, characterized in that The step of combining the local oscillator light with the quantum state to form beat frequency light comprises: Evenly dividing the quantum state into a first quantum state and a second quantum state; The local oscillation light is evenly divided into a first local oscillation light and a second local oscillation light; the phase of the first local oscillation light is a first phase, and the phase of the second local oscillation light is a second phase; The first path of local oscillator light is combined with the first path of quantum state to form a first beat frequency light, and the second path of local oscillator light is combined with the second path of quantum state to form a second beat frequency light.

5. The method according to claim 4, characterized in that The first detection result is obtained by the first beat frequency light, the second detection result is obtained by the second beat frequency light, the change amount of the signal to be measured is obtained based on the detection result, and the detection signal is obtained by calculation according to the change amount, including: Calculating a sum of squares of the first detection result and the second detection result; When a weak measurement condition is met, an approximate value of the sum of squares is obtained; the weak measurement condition is that the phase parameter corresponding to the signal to be measured is much smaller than the post-selection angle; Obtaining a change amount of the signal to be measured according to the approximate value; The signal to be tested is restored according to the change amount to obtain the detection signal.

6. A device for weak measurement sensing based on coherent states, characterized in that: include: Acquisition module, input module, detection module and recovery module; The acquisition module is used to acquire local oscillator light and signal light; the signal light is in a coherent state; The input module is used to input the signal light into the weak measurement unit based on the signal to be measured to obtain the quantum state of the signal light; The detection module is used to perform heterodyne detection on the quantum state using the local oscillator light to obtain a detection result; The recovery module is used to obtain the change amount of the signal to be detected based on the detection result, and calculate the detection signal according to the change amount.

7. A system based on weak measurement sensing of coherent states, characterized in that: For implementing the method according to any one of claims 1 to 5, the system comprises: A light source, used for generating local oscillator light and coherent state signal light; A weak measurement unit, used for receiving a signal to be measured and the signal light, and outputting a quantum state of the signal light; The processing unit is used to split and calculate the optical signal to obtain the detection signal.

8. The system according to claim 7, characterized in that The light source includes a coherent state light source and a local oscillation light source, the coherent state light source generates the signal light, and the local oscillation light source generates the local oscillation light.

9. The system according to claim 7, characterized in that The weak measurement unit is composed of a front selection subunit, a weak coupling subunit and a rear selection subunit.

10. The system according to claim 7, characterized in that The processing unit is composed of a beam splitter, a phase shifter, a detector and a differential circuit.

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