A method, device and system for weak measurement sensing based on coherent states

Abstract

The present application discloses a method, device and system for weak measurement sensing based on coherent states. Based on 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, and the signal light is input into the weak measurement unit to obtain the quantum state of the signal light. 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 on 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.

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 technologies, and therefore performs excellently in gravitational wave detection, inertial navigation systems, magnetometers and other fields.

[0003] Existing techniques, such as weak-value amplification, can improve measurement accuracy by setting a post-selection state that is nearly perpendicular to the pre-selection state. However, this method results in a relatively weak measurement signal, or intensity. When applied to quantum sensing, weak-value amplification makes the measurement signal difficult to detect, resulting in inaccurate measurements. Therefore, how to utilize quantum sensing technology while maintaining high measurement accuracy has become a pressing issue. 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] Acquiring local oscillator light and signal light; the signal light is in a coherent state;

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

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

[0009] The change amount of the signal to be measured is obtained based on the detection result, and the detection signal is calculated 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 that is approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset.

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

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

[0016] The beat frequency light is detected by a detector and then 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] Evenly dividing the local oscillation light into a first path of local oscillation light and a second path of local oscillation light; the phase of the first path of local oscillation light is a first phase, and the phase of the second path of local oscillation light is a second phase;

[0020] The first local oscillator light is combined with the first quantum state to form a first beat frequency light, and the second local oscillator light is combined with the second 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 acquiring of the change amount of the signal to be measured based on the detection results and the calculating of the detection signal according to the change amount include:

[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 square sum 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 measured 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 states, the present application also discloses a device for weak measurement sensing based on coherent states, comprising: 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 configured 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 configured to obtain a change in the signal to be measured based on the detection result, and calculate the detection signal according to the change.

[0031] Optionally, the input module includes:

[0032] a pre-selection submodule, configured to modulate the coherent state of the signal light into a pre-selection state;

[0033] A weak coupling submodule, configured to introduce the signal to be measured so as to cause weak coupling between the signal light and the weak measurement unit;

[0034] The post-selection submodule is used to project the weakly coupled signal light onto 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, configured to combine 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 the beat frequency light is detected by the 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 for evenly dividing the local oscillation light into a first path of local oscillation light and a second path of local oscillation light; the phase of the first path of local oscillation light is a first phase, and the phase of the second path of local oscillation light is a second phase;

[0041] The combining submodule is configured 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 from the first beat frequency light, the second detection result is obtained from the second beat frequency light, and the recovery module includes:

[0043] a summation submodule, configured to calculate the sum of the squares of the first detection result and the second detection result;

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

[0045] a calculation submodule, configured to obtain a change in the signal to be measured according to the approximate value;

[0046] The recovery submodule is configured to recover the signal to be measured 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 further discloses a system of weak measurement sensing based on coherent states, which is used to implement the above-mentioned method. The system includes:

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

[0049] A weak measurement unit, configured to receive a signal to be measured and the signal light, and output a quantum state of the signal light;

[0050] The processing unit is used to perform light splitting and calculation on the optical signal to obtain the detection signal.

[0051] Optionally, the light source includes a coherent light source and a local oscillation light source, the coherent 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. Based on 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, and the signal light is input into the weak measurement unit to obtain the quantum state of the signal light. 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 heterodyned by 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 on 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without 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 This is a schematic structural diagram 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 structural diagram 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 this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0061] Example 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, a signal light source and a 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 canonical 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. The canonical components of the coherent state refer to the two fundamental variables of the coherent state in phase space: the canonical position component and the canonical momentum component. 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, input the signal light 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. When light passes through these optical devices, it passes 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-selected state subunit in the weak measurement unit, the coherent state of the signal light is modulated into the pre-selected state. As an alternative method, the coherent state of the signal light can be expressed as |Ψ0>=|i>|α>, where the expression of the pre-selected 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, a signal to be measured is introduced into a weakly coupled subunit within a weak measurement unit. The signal to be measured can be understood as the signal to be sensed, such as an acoustic signal, temperature signal, or voltage. In the weakly coupled subunit, the signal to be measured causes weak coupling between the signal light and the weak measurement unit. In other words, the composite system consisting of the quantum system and the weak measurement unit begins to evolve over time, and this evolutionary process generally follows fundamental 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, 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 onto 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 can be obtained, namely the weak value. 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. Simply put, it is the signal obtained by changing the mathematical or physical form of the signal light. This quantum state can be expressed as follows:

[0080]

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

[0082] The basic principle of heterodyne detection is the coherence of two light waves. Local oscillator (LO) light is added to the signal light while receiving it. The LO light has a frequency very close to the signal light, causing the LO light and the signal light to form a beat signal on the photosensitive surface of the photodetector. The detector then responds 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 by 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 and input into the differential circuit, the first detection result can be obtained, which is expressed as |α Lo |x f (t).

[0086] Correspondingly, the second local oscillator light can be set to a second phase of π / 2 by the phase shifter, and then combined with the quantum state of the second signal light in the beam splitter to form a 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, a phase shifter is used to set the phase of the first local oscillator light to a first phase and the phase of the second local oscillator light to a second phase. For example, the first phase can be 0, the second phase can be π / 2, and the sum of the two phases can be π / 2. The specific values ​​can be set according to actual needs and are not limited here.

[0091] Step 104: Obtain a 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. 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, the signal to be measured is recovered 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 utilizing quantum resources to perform high-precision and high-sensitivity detection on 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 based on the change. High-sensitivity perception of tiny signals is achieved. This enriches the carriers selected for the weak measurement system and expands 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] Example 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 entire 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 so, proceed to step 210. If not, 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 the approximate value.

[0108] Step 211: Restore the signal to be measured 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 for weak measurement sensing based on coherent states 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 configured to input the signal light into a weak measurement unit based on a signal to be measured to obtain a quantum state of the signal light;

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

[0113] The recovery module 304 is configured to obtain a change in the signal to be measured based on the detection result, and calculate the detection signal according to the change.

[0114] Optionally, the input module 302 includes:

[0115] a pre-selection submodule, configured to modulate the coherent state of the signal light into a pre-selection state;

[0116] A weak coupling submodule, configured to introduce the signal to be measured so as to cause weak coupling between the signal light and the weak measurement unit;

[0117] The post-selection submodule is used to project the weakly coupled signal light onto 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, configured to combine 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 the beat frequency light is detected by the 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 for evenly dividing the local oscillation light into a first path of local oscillation light and a second path of local oscillation light; the phase of the first path of local oscillation light is a first phase, and the phase of the second path of local oscillation light is a second phase;

[0124] The combining submodule is configured 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 from the first beat frequency light, and the second detection result is obtained from the second beat frequency light. The recovery module 304 includes:

[0126] a summation submodule, configured to calculate the sum of the squares of the first detection result and the second detection result;

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

[0128] a calculation submodule, configured to obtain a change in the signal to be measured according to the approximate value;

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

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

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

[0132] A weak measurement unit, configured to receive a signal to be measured and the signal light, and output a quantum state of the signal light;

[0133] The processing unit is used to perform light splitting and calculation on the optical signal to obtain the detection signal.

[0134] In the system described in this embodiment, Figure 4 This is a structural diagram 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 for generating 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 beam splitter 7, and the local oscillator light is also split by beam splitter 6. The first local oscillator light passes through phase shifter 8 and is input into beam splitter 9 together with the first quantum state. The second local oscillator light passes through phase shifter 13 and is input into beam splitter 14 together with the second quantum state.

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

[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 document, relational terms such as first and second, etc., are used only 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 "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0140] The steps of the methods or algorithms 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), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, 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 with each other or combined to enable professional and technical personnel in this field to implement or use this application.

[0142] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one 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 is not limited to the embodiments shown herein, but is intended to 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, inputting the signal light into a weak measurement unit to obtain the quantum state of the signal light; Performing heterodyne detection on the quantum state using the local oscillator light to obtain a detection result; Acquiring a change amount of the signal to be measured based on the detection result, and calculating a detection signal according to the change amount; 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 includes: 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; Projecting the weakly coupled signal light onto a post-selection state approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset; The heterodyne detection of the quantum state using the local oscillator light includes: combining the local oscillator light with the quantum state to form beat frequency light; The beat frequency light is detected by a detector and then input into a differential circuit to obtain the detection result.

2. The method according to claim 1, characterized in that Combining the local oscillator light with the quantum state to form beat frequency light includes: Evenly dividing the quantum state into a first quantum state and a second quantum state; Evenly dividing the local oscillation light into a first path of local oscillation light and a second path of local oscillation light; the phase of the first path of local oscillation light is a first phase, and the phase of the second path of local oscillation light is a second phase; The first local oscillator light is combined with the first quantum state to form a first beat frequency light, and the second local oscillator light is combined with the second quantum state to form a second beat frequency light.

3. The method according to claim 2, 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, and the change amount of the signal to be measured is obtained based on the detection results, and the detection signal is calculated 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 square sum 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 measured is restored according to the change amount to obtain the detection signal.

4. 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 configured 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 configured to obtain a change in the signal to be measured based on the detection result, and calculate a detection signal according to the change; 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 includes: 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; Projecting the weakly coupled signal light onto a post-selection state approximately orthogonal to the pre-selection state to obtain the quantum state; the post-selection state is preset; The heterodyne detection of the quantum state using the local oscillator light includes: combining the local oscillator light with the quantum state to form beat frequency light; The beat frequency light is detected by a detector and then input into a differential circuit to obtain the detection result.

5. 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 3, the system comprises: A light source for generating local oscillator light and coherent signal light; A weak measurement unit, configured to receive a signal to be measured and the signal light, and output a quantum state of the signal light; The processing unit is used to perform light splitting and calculation on the optical signal to obtain the detection signal.

6. The system according to claim 5, characterized in that The light source includes a coherent light source and a local oscillation light source. The coherent light source generates the signal light, and the local oscillation light source generates the local oscillation light.

7. The system according to claim 5, characterized in that The weak measurement unit consists of a front selection subunit, a weak coupling subunit and a rear selection subunit.

8. The system according to claim 5, characterized in that The processing unit consists of a beam splitter, a phase shifter, a detector and a differential circuit.

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