Method for measuring interaction strength between two Rydberg atom ensembles

Abstract

The invention discloses a method for measuring interaction strength between two Rydberg atom ensembles. The method comprises the following steps: S1, preparing a first Rydberg atom ensemble A and a second Rydberg atom ensemble B; s2, respectively measuring to obtain a single group energy level frequency shift of the first Rydberg atom ensemble A and a single group energy level frequency shift of the second Rydberg atom ensemble B; s3, measuring to obtain a combined energy level frequency shift in a coupling state; s4, the interaction intensity VAB between the first Rydberg atom ensemble A and the second Rydberg atom ensemble B is obtained through calculation. According to the method, the single-group frequency shift of the two ensembles in the isolated state and the combined frequency shift of the two ensembles in the coupled state are measured respectively, and the interaction intensity between the ensembles is indirectly calculated according to the single-group frequency shift and the combined frequency shift, so that non-destructive measurement which can be dynamically monitored in real time and has high system universality is realized.

Description

Technical Field

[0001] This invention relates to the field of quantum physics measurement and precision measurement technology, specifically to a method for measuring the interaction strength between two Rydberg atomic ensembles. Background Technology

[0002] In cutting-edge research areas such as quantum many-body physics, quantum networks, and quantum sensing, Rydberg atoms, due to their strong interactions, long coherence times, and high sensitivity to external fields, have become an important physical platform for realizing quantum simulation, quantum information processing, and high-precision sensing. Among these, the precise measurement and manipulation of the coupling strength between two spatially separated ensembles of Rydberg atoms is a key technological foundation for constructing quantum network nodes, realizing distributed quantum sensing, and studying many-body quantum dynamics.

[0003] However, existing methods for measuring interactions between Rydberg atomic ensembles have significant technical limitations: First, direct detection methods (such as measuring macroscopic electric dipole moments) often require strong interference to the system, leading to irreversible collapse or decoherence of the quantum state and destroying the quantum properties of the system; second, existing methods are difficult to monitor the interaction strength in real time and dynamically, and most can only obtain the interaction strength after steady state or time averaging, and cannot observe its transient evolution process; third, many existing schemes rely on specific experimental architectures (such as high-quality optical resonators, precisely arranged optical lattices, etc.), which are complex and have low compatibility, making them difficult to apply flexibly to different atomic systems or experimental platforms.

[0004] Therefore, in order to address the above problems, developing a method for measuring the interaction strength that can maintain quantum coherence, support real-time dynamic monitoring, and has high system universality is of great significance for promoting the development of quantum technology. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a method for measuring the interaction strength between two Rydberg atomic ensembles. This method measures the single-cluster frequency shift of the two ensembles in the isolated state and the joint frequency shift in the coupled state, and indirectly calculates the interaction strength between the ensembles based on these measurements. This achieves a non-destructive, real-time dynamic monitoring method with high system universality.

[0006] To achieve the objective of this invention, the following solution is adopted: A method for measuring the interaction strength between two Rydberg atomic ensembles includes the following steps: S1: Prepare the first Rydberg ensemble A and the second Rydberg ensemble B; S2: Under the condition that the first Rydberg ensemble A and the second Rydberg ensemble B are not coupled, the single-group energy level frequency shift of the first Rydberg ensemble A and the single-group energy level frequency shift of the second Rydberg ensemble B are measured respectively. S3: Place the first Rydberg ensemble A and the second Rydberg ensemble B at a preset spatial distance, so that they interact and measure the frequency shift of the joint energy level in the coupled state; S4: Based on the single-group energy level shifts of the first Rydberg ensemble A, the single-group energy level shifts of the second Rydberg ensemble B, and the joint energy level shift, the interaction strength V between the first Rydberg ensemble A and the second Rydberg ensemble B is calculated. AB .

[0007] Furthermore, the interaction strength V AB Calculated using the following formula: in, , , , The frequency shifts of individual energy levels in the first Rydberg ensemble A and the second Rydberg ensemble B are respectively. , These represent the interatomic interaction strengths within the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. , The Rydberg number densities are those of the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. This represents the frequency shift of the joint energy level in the coupled state.

[0008] Furthermore, the method for measuring the interaction strength between two Rydberg ensembles further includes step S5: monitoring the interaction strength V in real time by adjusting the preset spatial distance between the first Rydberg ensemble A and the second Rydberg ensemble B. AB The trend of change of the preset spatial distance; Alternatively, the interaction strength V can be monitored in real time by adjusting the Rydberg atom number density of the first Rydberg ensemble A and the second Rydberg ensemble B. AB The trend of the change in the Rydberg atomic number density.

[0009] Furthermore, the first Rydberg ensemble A and the second Rydberg ensemble B are prepared by laser excitation of alkali metal atoms; the alkali metal atoms include rubidium atoms or cesium atoms.

[0010] Furthermore, the laser excites the alkali metal atoms to a specific high Rydberg state.

[0011] Furthermore, the specific Gorridberg state includes the 63D5 / 2 state.

[0012] Furthermore, when measuring the single-cluster energy level shift of the first Rydberg ensemble A, the single-cluster energy level shift of the second Rydberg ensemble B, and the joint energy level shift, weak probe light is used for spectral reading to achieve non-destructive or perturbative measurement of atomic quantum states.

[0013] Furthermore, the spectral reading specifically involves: using a frequency-tunable probe laser to monitor the transition frequency of Rydberg atoms to the 64P3 / 2 state, and accurately measuring the single-group energy level shift of the first Rydberg atom ensemble A, the single-group energy level shift of the second Rydberg atom ensemble B, and the joint energy level shift through frequency locking or spectral scanning techniques.

[0014] Furthermore, in step S1, by adjusting the wavelength of the excitation laser, atoms are excited to different target Rydberg states to independently or jointly change the Rydberg principal quantum numbers of the first Rydberg atom ensemble A and / or the second Rydberg atom ensemble B; in order to study the interaction strength V. AB Dependence on the Rydberg principal quantum number.

[0015] Furthermore, in step S3, the preset spatial distance is systematically changed to obtain the interaction strength V. AB The curve showing how the distance changes verifies its agreement with the theoretical model.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves non-destructive or perturbative measurement, effectively preserving the quantum coherence of the system. By measuring energy level frequency shifts rather than directly probing strongly interfering physical quantities such as electric dipole moments, this invention requires only weak probe light for spectral readout, resulting in minimal perturbation to the atomic quantum states. This avoids the irreversible destruction of quantum states caused by existing direct detection methods, allowing the system to retain its quantum properties after measurement, thus enabling subsequent quantum manipulation or long-term dynamical studies.

[0017] 2. This invention possesses the capability for real-time, dynamic monitoring of interaction strength. By adjusting the spatial distance between two atomic ensembles to change their coupling state and measuring the energy level frequency shifts before and after coupling, this invention can calculate the instantaneous interaction strength in real time. This feature allows the operator to continuously change the distance and obtain the dynamic evolution of the interaction strength as a function of this parameter, thereby overcoming the limitations of most existing methods that are limited to measuring steady-state or time-averaged values.

[0018] 3. This invention possesses excellent system universality and compatibility. This invention does not impose mandatory limitations on the types of atoms or specific excited states; its measurement principle is based on the universal relationship between energy level frequency shifts and interactions. Therefore, this scheme does not rely on complex structures such as optical resonators or specific lattices, and can be flexibly applied to various alkali metal atomic systems such as rubidium and cesium, as well as different Rydberg states, significantly improving the applicability of the method and the compatibility of experimental platforms.

[0019] 4. The measurement process of this invention is logically clear, and the results are highly accurate and repeatable. This invention establishes a baseline by first measuring the bulk level shifts of two atomic ensembles under uncoupled conditions, then measuring their coupled joint frequency shift, and finally calculating the interaction contribution between the ensembles from the total effect. This logical chain, consisting of baseline measurement, coupled measurement, and differential calculation, is clear and rigorous, effectively removing background interference from the interactions within each ensemble, thus ensuring that the final inter-ensemble interaction strength has high accuracy and good repeatability. Attached Figure Description

[0020] Figure 1 This is a flowchart of a method for measuring the interaction strength between two Rydberg atom ensembles in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the principle of a method for measuring the interaction strength between two Rydberg atomic ensembles in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the optical path of the experimental apparatus in the method for measuring the interaction strength between two Rydberg atom ensembles in an embodiment of the present invention; Figure 4 The interaction strength measured in the embodiments of the present invention A schematic diagram showing the curve of how the distance d between the two atomic ensembles varies; Figure 5 The interaction strength measured in the embodiments of the present invention A schematic diagram of the curves showing the change in atomic number density with respect to the Rydberg atomic density. Detailed Implementation

[0022] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0023] This invention provides a method for measuring the interaction strength between two Rydberg atomic ensembles. By measuring the Rydberg level shifts of a single cluster and the coupled system, the interaction strength is deduced, thereby avoiding direct destruction of the atomic quantum state, maintaining the coherence of the system, and supporting continuous observation of the evolution of the interaction strength with parameters such as distance and density.

[0024] like Figure 1-5 As shown, the method for measuring the interaction strength between two Rydberg atomic ensembles according to an embodiment of the present invention includes the following steps: S1: Prepare the first Rydberg ensemble A and the second Rydberg ensemble B.

[0025] In this embodiment, a first Rydberg ensemble A and a second Rydberg ensemble B, which are independent of each other, are prepared, for example, by laser excitation of atoms in a rubidium atom gas cell to a specific Rydberg state (such as 63D). 5 / 2 ).

[0026] S2: Under the condition that the first Rydberg ensemble A and the second Rydberg ensemble B are not coupled, the single-group energy level frequency shift of the first Rydberg ensemble A and the single-group energy level frequency shift of the second Rydberg ensemble B are measured respectively.

[0027] S3: Place the first Rydberg ensemble A and the second Rydberg ensemble B at a preset spatial distance to allow them to interact, and measure the frequency shift of the joint energy level in the coupled state.

[0028] In this embodiment, the first Rydberg ensemble A and the second Rydberg ensemble B are brought closer together by a controllable distance d to enhance their interaction, and the energy level frequency shift of the coupled system is measured at this time. .

[0029] S4: Based on the single-group energy level shifts of the first Rydberg ensemble A, the single-group energy level shifts of the second Rydberg ensemble B, and the joint energy level shift, the interaction strength V between the first Rydberg ensemble A and the second Rydberg ensemble B is calculated. AB .

[0030] In this embodiment, the distance d between the first Rydberg ensemble A and the second Rydberg ensemble B can be changed in real time by adjusting the laser power to change the Rydberg atom number density of a certain ensemble. The changing trends of these parameters.

[0031] Furthermore, the interaction strength V AB Calculated using the following formula: in, , , , The frequency shifts of individual energy levels in the first Rydberg ensemble A and the second Rydberg ensemble B are respectively. , These represent the interatomic interaction strengths within the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. , The Rydberg number densities are those of the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. This represents the frequency shift of the joint energy level in the coupled state. The overall trend shows that it decreases as the distance d increases, which is related to factors such as atomic dipole moment.

[0032] Furthermore, the method for measuring the interaction strength between two Rydberg ensembles further includes step S5: monitoring the interaction strength V in real time by adjusting the preset spatial distance between the first Rydberg ensemble A and the second Rydberg ensemble B. AB The trend of change of the preset spatial distance; Alternatively, the interaction strength V can be monitored in real time by adjusting the Rydberg atom number density of the first Rydberg ensemble A and the second Rydberg ensemble B. AB The trend of the change in the Rydberg atomic number density.

[0033] Furthermore, the first Rydberg ensemble A and the second Rydberg ensemble B are prepared by laser excitation of alkali metal atoms; the alkali metal atoms include rubidium atoms or cesium atoms.

[0034] Furthermore, the laser excites the alkali metal atoms to a specific high Rydberg state.

[0035] Furthermore, the specific Gorridberg state includes the 63D5 / 2 state.

[0036] Furthermore, when measuring the single-cluster energy level shift of the first Rydberg ensemble A, the single-cluster energy level shift of the second Rydberg ensemble B, and the joint energy level shift, weak probe light is used for spectral reading to achieve non-destructive or perturbative measurement of atomic quantum states.

[0037] Furthermore, the spectral reading specifically involves: using a frequency-tunable probe laser to monitor the transition frequency of Rydberg atoms to the 64P3 / 2 state, and accurately measuring the single-group energy level shift of the first Rydberg atom ensemble A, the single-group energy level shift of the second Rydberg atom ensemble B, and the joint energy level shift through frequency locking or spectral scanning techniques.

[0038] Furthermore, in step S1, by adjusting the wavelength of the excitation laser, atoms are excited to different target Rydberg states to independently or jointly change the Rydberg principal quantum numbers of the first Rydberg atom ensemble A and / or the second Rydberg atom ensemble B; in order to study the interaction strength V. AB Dependence on the Rydberg principal quantum number.

[0039] Furthermore, in step S3, the preset spatial distance is systematically changed to obtain the interaction strength V. AB The curve showing how the distance changes verifies its agreement with the theoretical model.

[0040] The method for measuring the interaction strength between two Rydberg atomic ensembles in this invention involves preparing two independent Rydberg atomic ensembles, measuring their energy level shifts separately, and indirectly calculating the interaction strength between the two ensembles based on the energy level frequency shift when the two ensembles are coupled. This method avoids the destruction of quantum states caused by direct electric dipole moment measurement, maintains the quantum coherence of the atomic system, is suitable for long-term dynamic monitoring, and has good system universality, applicable to various atomic systems such as rubidium and cesium, and different Rydberg states. This method provides an effective experimental measurement tool for quantum many-body systems, quantum networks, and high-sensitivity quantum sensing.

[0041] The method for measuring the interaction strength between two Rydberg atomic ensembles according to embodiments of the present invention has the following technical advantages: 1. The system exhibits good stability and strong adaptability. This invention is applicable to ensemble scales, and the system operates stably and reliably. The measurement process is flexible in controlling external fields, highly adaptable, and compatible with various experimental platforms, demonstrating good portability and platform compatibility.

[0042] 2. High measurement sensitivity and well-defined spatial resolution. This invention utilizes electromagnetically induced transparent quantum interference spectroscopy to detect extremely weak energy level shifts down to the kHz or even Hz level, achieving highly sensitive measurements of weak interactions. By independently preparing and manipulating two spatially separated atomic ensembles, the interaction between atomic sets within two specific spatial regions can be precisely located and measured, exhibiting well-defined spatial resolution.

[0043] 3. Non-destructive measurement, supporting long-term dynamic monitoring. This invention uses weak probe light for spectral reading, which causes minimal disturbance to the atomic quantum state, achieving near-non-destructive measurement and effectively maintaining the quantum coherence of the system. It is suitable for long-term continuous monitoring of quantum dynamic processes.

[0044] 4. Flexible parameter control facilitates systematic research. This invention allows for flexible study of the dependence of interaction strength on various physical conditions by adjusting multiple parameters such as the applied magnetic field, electric field, distance between two ensembles, Rydberg atomic number density, and principal quantum number, providing reliable experimental evidence for the verification and optimization of theoretical models.

[0045] 5. The system is simple and the results are accurate and reliable. Based on mature spectroscopic techniques, this invention eliminates the need for complex single-photon conversion or coincidence counting systems, significantly reducing experimental complexity and cost. Through a clear measurement and calculation process, background interference is effectively suppressed, resulting in highly accurate and reproducible interaction intensity data.

[0046] The following uses rubidium atoms as an example to illustrate the method for measuring the interaction strength between two Rydberg atom ensembles in an embodiment of the present invention.

[0047] Example: Taking rubidium atoms as an example, the atoms are excited from the ground state to the 63D state using a laser with a wavelength of 480nm. 5 / 2 The Rydberg states form two spatially separated Rydberg atom ensembles, A and B. The distance d between the two ensembles is controlled by a precise displacement platform. A frequency-tunable probe laser is used to monitor the orientation of the Rydberg atoms towards 64P. 3 / 2 The transition frequencies of the states are precisely measured using frequency locking or spectral scanning techniques to measure the energy level shifts in single-cluster and coupled states.

[0048] During data processing, the single-cluster frequency shift is calibrated first. and Then measure the coupling frequency shift. According to the formula Calculate the interaction strength. By varying the distance d (from a few millimeters to tens of millimeters), we obtain... The relationship curve is consistent with theoretical expectations. Similarly, by changing the laser power excitation of the B group to adjust its Rydberg atom number density, the relationship can be observed. With the change in Rydberg atomic number density.

[0049] The method for measuring the interaction strength between two Rydberg atomic ensembles according to the present invention has the advantages of being non-destructive, maintaining quantum coherence, real-time dynamic monitoring, and having strong system universality. It can be widely used in quantum many-body dynamics research, high-precision atomic clock frequency stabilization, detection of weak biological magnetic signals, quantum radar and stealth material testing, and other fields.

[0050] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for measuring the interaction strength between two Rydberg atomic ensembles, characterized in that, Includes the following steps: S1: Prepare the first Rydberg ensemble A and the second Rydberg ensemble B; S2: Under the condition that the first Rydberg ensemble A and the second Rydberg ensemble B are not coupled, the single-group energy level frequency shift of the first Rydberg ensemble A and the single-group energy level frequency shift of the second Rydberg ensemble B are measured respectively. S3: Place the first Rydberg ensemble A and the second Rydberg ensemble B at a preset spatial distance, so that they interact and measure the frequency shift of the joint energy level in the coupled state; S4: Based on the single-group energy level shifts of the first Rydberg ensemble A, the single-group energy level shifts of the second Rydberg ensemble B, and the joint energy level shift, the interaction strength V between the first Rydberg ensemble A and the second Rydberg ensemble B is calculated. AB .

2. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 1, characterized in that, The interaction strength V AB The following formula is used for calculation: in, , , , These are the single-group energy level frequency shifts of the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. , These represent the interatomic interaction strengths within the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. , The Rydberg number densities are those of the first Rydberg ensemble A and the second Rydberg ensemble B, respectively. This represents the frequency shift of the joint energy level in the coupled state.

3. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 1, characterized in that, The method also includes step S5: real-time monitoring of the interaction strength V by adjusting the preset spatial distance between the first Rydberg ensemble A and the second Rydberg ensemble B. AB The trend of change of the preset spatial distance; Alternatively, the interaction strength V can be monitored in real time by adjusting the Rydberg atom number density of the first Rydberg ensemble A and the second Rydberg ensemble B. AB The trend of the change in the Rydberg atomic number density.

4. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 1, characterized in that, The first Rydberg ensemble A and the second Rydberg ensemble B are prepared by laser excitation of alkali metal atoms; the alkali metal atoms include rubidium atoms or cesium atoms.

5. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 4, characterized in that, The laser excites the alkali metal atoms to a specific Gordian Rydberg state.

6. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 5, characterized in that, The specific Gorridberg states include the 63D5 / 2 state.

7. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 1, characterized in that, When measuring the single-cluster energy level shift of the first Rydberg ensemble A, the single-cluster energy level shift of the second Rydberg ensemble B, and the joint energy level shift, weak probe light is used for spectral reading to achieve non-destructive or perturbative measurement of atomic quantum states.

8. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 7, characterized in that, The spectral reading specifically involves: using a frequency-tunable probe laser to monitor the transition frequency of Rydberg atoms to the 64P3 / 2 state, and accurately measuring the single-group energy level shift of the first Rydberg atom ensemble A, the single-group energy level shift of the second Rydberg atom ensemble B, and the joint energy level shift through frequency locking or spectral scanning techniques.

9. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 1, characterized in that, In step S1, atoms are excited to different target Rydberg states by adjusting the wavelength of the excitation laser, thereby independently or jointly changing the Rydberg principal quantum numbers of the first Rydberg atom ensemble A and / or the second Rydberg atom ensemble B; in order to study the interaction strength V. AB Dependence on the Rydberg principal quantum number.

10. The method for measuring the interaction strength between two Rydberg atomic ensembles according to claim 1, characterized in that, In step S3, the preset spatial distance is systematically changed to obtain the interaction strength V. AB The curve showing how the distance changes verifies its agreement with the theoretical model.

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