A cold atom gravity measurement method and device based on entangled state enhancement

Abstract

The application provides a cold atom gravity measurement method and device based on entangled state enhancement, and belongs to the technical field of cold atom gravity measurement. The method comprises the following steps: exciting a nonlinear crystal to obtain a pair of entangled photons, wherein the entangled photons comprise a first photon and a second photon in an entangled state; controlling laser parameters of a region where a cold atom group is located, coupling the first photon into the cold atom group to obtain a plurality of cold atoms in an entangled state; placing the plurality of cold atoms in an entangled state in a gravity field, measuring a phase difference of the cold atoms under the action of the gravity field, and determining a gravity measurement result based on the phase difference. The application improves the measurement limit to the Heisenberg limit by introducing coupling of entangled photons and cold atoms, and realizes higher-precision gravity measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of cold atom gravity measurement, and in particular to a cold atom gravity measurement method and device based on entangled state enhancement. Background Art

[0002] Cold atom gravimeters are widely used in precision gravity measurements. Their principle is to cool atoms to a very low temperature near absolute zero and then use the influence of the gravitational field on their interference pattern to achieve measurement.

[0003] However, the measurement accuracy of cold atom gravimeters is mainly limited by the standard quantum limit (SQL). For geophysical exploration, geological exploration and basic physics experiments, this accuracy still cannot meet the requirements in many cases. ,in n This means that increasing the number of atoms is necessary to increase measurement accuracy, but too many atoms will increase cooling difficulty and system complexity.

[0004] Therefore, there is an urgent need to provide a cold atom gravity measurement method and device based on entangled state enhancement to improve measurement accuracy without increasing the number of atoms, so as to take into account both measurement accuracy and system simplicity. Summary of the Invention

[0005] In view of this, it is necessary to provide a cold atom gravity measurement method and device based on entangled state enhancement to solve the technical problems in the existing technology of improving measurement accuracy by increasing the number of atoms, resulting in higher cooling difficulty and system complexity.

[0006] On the one hand, in order to solve the above technical problems, the present invention provides a cold atom gravity measurement method based on entangled state enhancement, comprising:

[0007] Exciting the nonlinear crystal to obtain an entangled photon pair, wherein the entangled photon pair includes a first photon and a second photon in an entangled state;

[0008] Controlling laser parameters in the region where the cold atom cluster is located to couple the first photon into the cold atom cluster to obtain a plurality of cold atoms in an entangled state;

[0009] The plurality of cold atoms in an entangled state are placed in a gravitational field, the phase difference of the cold atoms under the action of the gravitational field is measured, and a gravity measurement result is determined based on the phase difference.

[0010] In one possible implementation, exciting a nonlinear crystal to obtain an entangled photon pair includes:

[0011] Obtaining a target parameter of a tunable laser source, adjusting pump light based on the target parameter, and obtaining target pump light;

[0012] Exciting the nonlinear crystal based on the target pump light, and obtaining the entangled photon pair.

[0013] In a possible implementation, after exciting the nonlinear crystal based on the target pump light and obtaining the entangled photon pair, the method further includes:

[0014] Adjusting a phase offset between the first photon and the second photon, and obtaining an enhanced entangled photon pair;

[0015] Processing the enhanced entangled photon pair based on a phase-locked amplification technology, and obtaining a stable entangled photon pair.

[0016] In a possible implementation, before coupling the first photon into the cold atom group and obtaining a plurality of cold atoms in an entangled state, the method further includes:

[0017] Obtaining a wavelength and a polarization state of the first photon and a target wavelength and coupling characteristics of the cold atom;

[0018] Adjusting the wavelength and the polarization state based on the target wavelength and the coupling characteristics.

[0019] In a possible implementation, the method of coupling the first photon into the cold atom group and obtaining a plurality of cold atoms in an entangled state includes:

[0020] Controlling laser parameters of a region where the cold atom group is located, and constructing an entanglement response of each of the cold atoms in the cold atom group to the first photon;

[0021] Obtaining the plurality of cold atoms in an entangled state based on interactions between the plurality of cold atoms and the entanglement response.

[0022] In a possible implementation, the method further includes:

[0023] Synchronously obtaining first phase data of the cold atom and second phase data of the first photon;

[0024] Determining a coupling strength of the entanglement response based on the first phase data and the second phase data;

[0025] When the coupling strength does not meet a requirement, adjusting the laser parameters so that the coupling strength of the entanglement response meets the requirement.

[0026] In a possible implementation, the laser parameters include a laser field frequency and a laser field phase.

[0027] In a possible implementation, the method further includes, before determining the gravity measurement result based on the phase difference, further including:

[0028] Noise filtering the phase difference.

[0029] In a possible implementation, after noise filtering the phase difference, further including:

[0030] Noise compensating the noise filtered phase difference based on a quantum noise compensation algorithm.

[0031] In another aspect, the present application also provides a cold atom gravity measurement device based on entangled state enhancement, comprising:

[0032] An entangled photon pair generation module is configured to excite a nonlinear crystal to obtain a pair of entangled photons, the pair of entangled photons including a first photon and a second photon in an entangled state.

[0033] A photon-cold atom coupling module is configured to control laser parameters of a region where a cold atom group is located, couple the first photon into the cold atom group, and obtain a plurality of cold atoms in an entangled state.

[0034] A gravity measurement module is configured to place the plurality of cold atoms in an entangled state in a gravitational field, measure a phase difference of the cold atoms under the action of the gravitational field, and determine a gravity measurement result based on the phase difference.

[0035] The present application has the following beneficial effects: the cold atom gravity measurement method based on entangled state enhancement provided by the present application obtains a pair of entangled photons by exciting a nonlinear crystal, couples the first photon of the pair of entangled photons into a cold atom group, and obtains a plurality of cold atoms in an entangled state, thereby providing additional quantum resources for cold atom gravity measurement, reducing phase uncertainty by utilizing quantum entanglement effect, and improving measurement precision from a standard quantum limit (1 / n) to a Heisenberg limit (1 / n), i.e., improving the measurement precision of cold atom gravity measurement. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 An embodiment flowchart of the cold atom gravity measurement method based on entangled state enhancement provided by the present application is shown.​

[0038] Figure 2 For the present invention Figure 1 A schematic flow chart of an embodiment of S101;

[0039] Figure 3 A schematic flow chart of an embodiment of adjusting the wavelength and polarization state of a first photon provided by the present invention;

[0040] Figure 4 For the present invention Figure 1 A schematic flow chart of an embodiment of S102;

[0041] Figure 5 A schematic diagram of a flow chart of an embodiment of adjusting the entanglement response provided by the present invention;

[0042] Figure 6 This is a schematic structural diagram of an embodiment of the cold atom gravity measurement device based on entangled state enhancement provided by the present invention. DETAILED DESCRIPTION

[0043] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0044] It should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present invention illustrate operations implemented according to some embodiments of the present invention. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps that have no logical contextual relationship can be reversed in order or implemented simultaneously. In addition, those skilled in the art, guided by the content of the present invention, can add one or more other operations to the flowcharts or remove one or more operations from the flowcharts. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.

[0045] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] The present invention provides a cold atom gravity measurement method and device based on entangled state enhancement, which are described below.

[0047] Figure 1 A schematic flow chart of an embodiment of the cold atom gravity measurement method based on entangled state enhancement provided by the present invention is shown in FIG. Figure 1 As shown, the cold atom gravity measurement method based on entangled state enhancement includes:

[0048] S101, exciting a nonlinear crystal to obtain an entangled photon pair, where the entangled photon pair includes a first photon and a second photon in an entangled state;

[0049] S102, controlling laser parameters in the region where the cold atom cluster is located, coupling the first photon into the cold atom cluster, and obtaining a plurality of cold atoms in an entangled state;

[0050] S103. Placing multiple cold atoms in an entangled state in a gravitational field, measuring the phase difference of the cold atoms under the action of the gravitational field, and determining the gravity measurement result based on the phase difference.

[0051] Specifically, the nonlinear crystal in step S101 is a lithium niobate crystal.

[0052] Among them, the first photon and the second photon in the entangled state have the same or similar frequencies and are separated in space, but maintain a quantum entanglement relationship, so that the state of one of the photons can be transferred to couple to the cold atomic cluster.

[0053] It should be understood that a cold atom cluster refers to a collection of multiple cold atoms.

[0054] Among them, cold atoms refer to: placing rubidium or cesium atoms in optical tweezers for cooling, cooling them to an ultra-low temperature state close to absolute zero (a few nanokelvins), and then configuring mutually perpendicular laser cooling axes to capture and cool the atoms through lasers, gradually reducing their speed to approach a static state. At this time, the atoms reach a superfluid state or Bose-Einstein condensate state.

[0055] The superfluid state or Bose-Einstein condensate can ensure that cold atoms have high coherence and long coherence time. Cold atomic clusters in ultra-low temperature state can realize collective coherent motion in quantum state, thereby stably maintaining quantum interference pattern in the gravitational field, greatly improving the accuracy of gravity measurement and reducing the interference of thermal noise on measurement.

[0056] It should be noted that the purpose of coupling the first photon into the cold atomic cluster in step S102 is to enable the atoms to capture and retain the phase information provided by the first photon.

[0057] It should be further explained that the phase difference of the cold atoms under the action of the gravity field in step S103 is specifically: the wave function of the cold atom group is divided into two parts through a beam splitter, two beams of light are obtained, the two beams of light are subjected to free evolution under the action of the gravity field, and a slight phase difference occurs in the process, the direction of the light beams after splitting is controlled based on a reflector, when the two beams of light are recombined, the interference fringes after the interference of the two beams of light are recorded based on a detector, and the phase difference obtained based on the interference fringes.

[0058] Since the gravity measurement result depends on the phase difference, in order to improve the measurement accuracy of the phase difference and further improve the measurement accuracy of the gravity measurement result, in some embodiments of the present application, the phase difference can be detected in real time based on a high-sensitivity quantum state detection system, so as to ensure that the measurement accuracy of the quantum state reaches the single-photon level.

[0059] Meanwhile, a fast-response photodetector and a time-resolved detector can also be provided to accurately detect and feed back the phase difference of the cold atoms in a short time, thereby improving the real-time response capability of the gravity measurement.

[0060] Compared with the prior art, the cold atom gravity measurement method based on entangled state enhancement provided by the embodiments of the present application obtains the first photon of the entangled photon pair by exciting the nonlinear crystal, couples the first photon of the entangled photon pair into the cold atom group, obtains a plurality of cold atoms in an entangled state, provides additional quantum resources for cold atom gravity measurement, reduces the phase uncertainty by using quantum entanglement effect, and improves the measurement accuracy from the standard quantum limit (1 / 2) to the Heisenberg limit (1 / n), that is, the measurement accuracy of the cold atom gravity measurement is improved.

[0061] In some embodiments of the present application, as shown in Figure 2 , step S101 comprises:

[0062] S201, obtaining a target parameter of the tunable laser source, adjusting the pump light based on the target parameter to obtain a target pump light;

[0063] S202, exciting the nonlinear crystal based on the target pump light to obtain an entangled photon pair.

[0064] The purpose of the target parameter is to make the generated entangled photon pair have strong quantum entanglement characteristics, so as to ensure the accuracy of subsequent gravity measurement.

[0065] Specifically, the target parameter can be the wavelength of the tunable laser source.

[0066] Further, the target parameter of the tunable laser source can also be a parameter related to the generation rate of the entangled photon pair and the purity of the entangled state, which will not be described one by one here.

[0067] ​It should be noted that: in some embodiments of the present application, the quantum entanglement characteristics of the generated entangled photon pairs can also be ensured by adjusting the nonlinear coefficient of the nonlinear crystal through the spontaneous parametric down-conversion (SPDC) effect of the nonlinear crystal.

[0068] From the above description, it can be seen that the entangled state of the plurality of cold atoms is crucial for gravity measurement results, and therefore, in some embodiments of the present application, the cold atom gravity measurement method based on the entangled state enhancement after step S202 further comprises:

[0069] Adjusting the phase offset between the first photon and the second photon to obtain an enhanced entangled photon pair;

[0070] Processing the enhanced entangled photon pair based on a phase-locked amplification technique to obtain a stable entangled photon pair.

[0071] The first photon and the second photon in step S101 are two photons in the stable entangled photon pair.

[0072] The embodiment of the present application enhances the coherence of the cold atom entangled state formation process by adjusting the phase offset of the first photon and the second photon, and by processing the enhanced entangled photon pair based on a phase-locked amplification technique, it can ensure that the generated stable entangled photon pair has a stable phase relationship, and ensure the phase control accuracy during subsequent gravity measurement.

[0073] To maximize the transmission efficiency of the phase information of the first photon in the cold atom group, in some embodiments of the present application, as shown in Figure 3 Before step S102, it further comprises:

[0074] S301, obtaining the wavelength and polarization state of the first photon and the target wavelength and coupling characteristics of the cold atom;

[0075] S302, adjusting the wavelength and polarization state based on the target wavelength and coupling characteristics.

[0076] The adjustment of the wavelength and polarization state can be realized by a wave plate and a polarization beam splitter.

[0077] The embodiment of the present application adjusts the wavelength and polarization state of the first photon based on the target wavelength and coupling characteristics of the cold atom, so that the first photon adapts to the wavelength and coupling characteristics of the cold atom, and then the transition frequency of the first photon and the cold atom is matched, thereby maximizing the transmission efficiency of the phase information of the first photon in the cold atom group.

[0078] In some embodiments of the present application, as shown in Figure 4 Step S102 comprises:

[0079] S401, control the laser parameter of the region where the cold atom group is located, and construct the entanglement response of each cold atom in the cold atom group and the first photon;

[0080] S402, obtain a plurality of cold atoms in an entangled state based on the interaction and entanglement response between the plurality of cold atoms.

[0081] It should be noted that the entanglement response of each cold atom in the cold atom group and the first photon is independent, therefore, the control of the laser parameter of the region where the cold atom group is located in step S401 should be the control of the laser parameter of each cold atom position, so as to ensure the construction of the entanglement response for each cold atom and the first photon.

[0082] The principle of obtaining a plurality of cold atoms in an entangled state in step S402 is that the first photon transmits phase information to the plurality of cold atoms through its coherence, and the plurality of cold atoms influence each other through group effect to obtain a plurality of cold atoms in an entangled state.

[0083] In specific embodiments of the present application, the laser parameter includes laser field frequency and laser field phase.

[0084] Since the entanglement response between the first photon and the cold atom may collapse or decay under the influence of external environment or other disturbances, resulting in the inability to accurately measure gravity, in order to avoid this problem, in some embodiments of the present application, as shown in Figure 5 The cold atom gravity measurement method based on entangled state enhancement further comprises:

[0085] S501, synchronously acquire first phase data of the cold atom and second phase data of the first photon;

[0086] S502, determine the coupling strength of the entanglement response based on the first phase data and the second phase data;

[0087] S503, when the coupling strength does not meet the requirement, adjust the laser parameter so that the coupling strength of the entanglement response meets the requirement.

[0088] The embodiment of the present application synchronously detects the first phase data of the cold atom and the second phase data of the first photon, and adjusts the laser parameter based on the detected coupling strength, which ensures that the coupling strength of the entanglement response under any condition, that is, when the entanglement response is unstable under the influence of external environment or disturbance, the adjustment is made quickly, ensuring the reliability and stability of the entanglement response, and further ensuring that the coherent information can be effectively transmitted to the cold atom, improving the accuracy of subsequent gravity measurement.

[0089] Moreover, the embodiment of the present application synchronously acquires the first phase data and the second phase data, avoiding the adverse effect of different acquisition times on the judgment of the coupling strength, and further ensuring the accuracy of gravity measurement.

[0090] Among them, the adjustment of laser parameters can be adjusted in real time through phase modulators and frequency modulators to ensure that the entangled response between the first photon and the cold atom remains stable throughout the measurement process.

[0091] Because quantum systems are susceptible to environmental influences (such as light and temperature), any interaction with the environment can lead to information leakage, causing the entangled state to gradually decay, a process known as decoherence. Decoherence is one of the major obstacles to overcome in quantum computing and quantum communication. To avoid this technical issue, in some embodiments of the present invention, before determining the gravity measurement result based on the phase difference in step S103, the following steps are further included:

[0092] Perform noise filtering on the phase difference.

[0093] The specific means of performing noise filtering on the phase difference is: measuring the phase difference noise based on a spectrum analyzer, and setting filtering parameters of the noise filter based on the phase difference noise, thereby achieving noise filtering.

[0094] The embodiment of the present invention eliminates noise interference caused by ambient light, temperature changes and other surrounding environments by performing noise filtering on the phase difference, thereby minimizing the error of the gravity measurement result.

[0095] To further improve the accuracy of gravity measurement results, in some embodiments of the present invention, after performing noise filtering on the phase difference, the following steps are further included:

[0096] The noise-filtered phase difference is compensated based on the quantum noise compensation algorithm.

[0097] The embodiment of the present invention can dynamically compensate for the measurement error caused by quantum noise by setting a quantum noise compensation algorithm, thereby further improving the accuracy of gravity measurement.

[0098] The quantum noise compensation algorithm may be any noise compensation algorithm in the prior art adapted to the embodiment of the present invention, and will not be described in detail here.

[0099] In summary, the cold atom gravity measurement method based on entangled state enhancement proposed in the embodiment of the present invention couples the first photon of the entangled photon pair into the cold atom group to obtain multiple cold atoms in an entangled state, providing additional quantum resources for cold atom gravity measurement, utilizing the quantum entanglement effect to reduce phase uncertainty, significantly reducing the phase noise of cold atom gravity measurement, and increasing the measurement accuracy from the standard quantum limit ( ) to the Heisenberg limit (1 / n), that is, the measurement accuracy of cold atom gravity measurement is improved, the measurement accuracy breaks through the standard quantum limit, and high-precision measurement of gravity signals is achieved.

[0100] In order to better implement the cold atom gravity measurement method based on entangled state enhancement in the embodiment of the present application, on the basis of the cold atom gravity measurement method based on entangled state enhancement, the present application also provides a cold atom gravity measurement device based on entangled state enhancement, as shown in Figure 6 The cold atom gravity measurement device based on entangled state enhancement 600 comprises:

[0101] The entangled photon pair generation module 601 is configured to excite the nonlinear crystal to obtain a pair of entangled photons, the entangled photons comprising a first photon and a second photon in an entangled state.

[0102] The photon-cold atom coupling module 602 is configured to control the laser parameters of the region where the cold atom group is located, couple the first photon into the cold atom group, and obtain a plurality of cold atoms in an entangled state.

[0103] The gravity measurement module 603 is configured to place the plurality of cold atoms in an entangled state in a gravitational field, measure the phase difference of the cold atoms under the action of the gravitational field, and determine the gravity measurement result based on the phase difference.

[0104] The cold atom gravity measurement device based on entangled state enhancement 600 provided by the above embodiment can realize the technical solutions described in the above cold atom gravity measurement method based on entangled state enhancement embodiment. The principles of the implementation of the above modules or units can be referred to the corresponding content in the above cold atom gravity measurement method based on entangled state enhancement embodiment, which will not be described here.

[0105] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing relevant hardware (such as a processor, a controller, etc.) to complete. The computer program can be stored in a computer readable storage medium. The computer readable storage medium includes a magnetic disk, an optical disk, a read-only memory, a random access memory, etc.

[0106] The cold atom gravity measurement method and device based on entangled state enhancement provided by the present application are described in detail above. The principles and implementation modes of the present application are described by applying specific examples. The above embodiment is only used to help understand the method and its core idea of the present application. For those skilled in the art, according to the idea of the present application, the specific implementation mode and application range can be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A cold atom gravity measurement method based on entangled state enhancement, characterized in that: include: Exciting the nonlinear crystal to obtain an entangled photon pair, wherein the entangled photon pair includes a first photon and a second photon in an entangled state; Controlling laser parameters in the region where the cold atom cluster is located to couple the first photon into the cold atom cluster to obtain a plurality of cold atoms in an entangled state; placing the plurality of cold atoms in an entangled state in a gravitational field, measuring a phase difference of the cold atoms under the action of the gravitational field, and determining a gravity measurement result based on the phase difference; Controlling laser parameters in the region where the cold atom cluster is located, coupling the first photon into the cold atom cluster, and obtaining a plurality of cold atoms in an entangled state, comprising: Controlling laser parameters in the region where the cold atom cluster is located to construct an entangled response between each of the cold atoms in the cold atom cluster and the first photon; Based on the interaction between the plurality of cold atoms and the entangled response, the plurality of cold atoms in an entangled state are obtained.

2. The cold atom gravity measurement method based on entangled state enhancement according to claim 1, characterized in that: Excite the nonlinear crystal to obtain an entangled photon pair, including: Acquiring target parameters of the tunable laser source, and adjusting the pump light based on the target parameters to obtain target pump light; The nonlinear crystal is excited based on the target pump light to obtain the entangled photon pair.

3. The cold atom gravity measurement method based on entangled state enhancement according to claim 2, characterized in that: After exciting the nonlinear crystal based on the target pump light to obtain the entangled photon pair, the method further includes: adjusting a phase shift between the first photon and the second photon to obtain an enhanced entangled photon pair; The enhanced entangled photon pairs are processed based on phase-locked amplification technology to obtain stable entangled photon pairs.

4. The cold atom gravity measurement method based on entangled state enhancement according to claim 1, characterized in that: Before coupling the first photon into the cold atom group to obtain a plurality of cold atoms in an entangled state, the method further includes: Acquiring the wavelength and polarization state of the first photon and the target wavelength and coupling characteristics of the cold atom; The wavelength and the polarization state are adjusted based on the target wavelength and the coupling characteristic.

5. The cold atom gravity measurement method based on entangled state enhancement according to claim 1, characterized in that: The method further comprises: synchronously acquiring first phase data of the cold atom and second phase data of the first photon; determining a coupling strength of the entangled response based on the first phase data and the second phase data; When the coupling strength does not meet the requirement, the laser parameters are adjusted so that the coupling strength of the entangled response meets the requirement.

6. The cold atom gravity measurement method based on entangled state enhancement according to any one of claims 1 to 5, characterized in that: The laser parameters include laser field frequency and laser field phase.

7. The cold atom gravity measurement method based on entangled state enhancement according to claim 1, characterized in that: The method further includes, before determining a gravity measurement result based on the phase difference, the following steps: Noise filtering is performed on the phase difference.

8. The cold atom gravity measurement method based on entangled state enhancement according to claim 1, characterized in that: After performing noise filtering on the phase difference, the method further includes: The noise-filtered phase difference is compensated based on the quantum noise compensation algorithm.

9. A cold atom gravity measurement device based on entangled state enhancement, characterized in that: include: an entangled photon pair generation module, configured to excite the nonlinear crystal to obtain an entangled photon pair, wherein the entangled photon pair includes a first photon and a second photon in an entangled state; a photon-cold atom coupling module, configured to control laser parameters in the region where the cold atom cluster is located, and couple the first photon into the cold atom cluster to obtain a plurality of cold atoms in an entangled state; a gravity measurement module, configured to place the plurality of cold atoms in an entangled state in a gravity field, measure a phase difference of the cold atoms under the action of the gravity field, and determine a gravity measurement result based on the phase difference; Controlling laser parameters in the region where the cold atom cluster is located, coupling the first photon into the cold atom cluster, and obtaining a plurality of cold atoms in an entangled state, comprising: Controlling laser parameters in the region where the cold atom cluster is located to construct an entangled response between each of the cold atoms in the cold atom cluster and the first photon; Based on the interaction between the plurality of cold atoms and the entangled response, the plurality of cold atoms in an entangled state are obtained.

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