Dynamic nonreciprocity modulation method and system based on double-cavity coupling and storage medium

Abstract

The invention discloses a dynamic nonreciprocity modulation method and system based on double-cavity coupling and a storage medium. The method comprises the following steps: establishing a double-atom-double-cavity waveguide QED system model; calculating a momentum equation of the double-atom-double-cavity waveguide QED system; calculating a transmittance expression of photons according to the momentum equation; non-reciprocity modulation of photon transmission is realized by modulating atomic frequency and / or mutual coupling strength of the double cavities. According to the invention, the problem that effective photon non-reciprocal transmission is difficult to realize in a broadband range in the prior art is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of quantum communication, and in particular relates to a dynamic non-reciprocal modulation method, system and storage medium based on dual-cavity coupling. Background Art

[0002] The transmission and reflection behavior of photons in waveguide QED systems has led to the rapid development of optical quantum devices, such as photon switches, quantum routing, optical isolation devices, etc. In recent years, various single-photon switches and photon routing have been realized through the study of parameters such as the coupling strength between cavity and atom, the coupling strength between waveguide and cavity, the dissipation between cavity and atom, the detuning between cavity and atom, and the effect of phase modulation on the transport properties of single photons.

[0003] However, due to practical conditions and technical barriers, the frequency of atoms in the cavity cannot be changed, and only the coupling strength is considered to be a constant. Time domain dynamic modulation is difficult to achieve, which is not conducive to the dynamic regulation of single photon transport, limiting its application in quantum information. At the same time, in the existing technology, the response of photons entering the system from different ends is difficult to distinguish, and effective non-reciprocal transmission can only adapt to certain selected frequency points, resulting in the reflected light field of other devices or systems affecting the signal source, reducing the reliability of optical quantum devices.

[0004] In order to solve the problem of difficulty in achieving effective non-reciprocal transmission of photons in a wide frequency range, a dynamic non-reciprocal modulation method, system and storage medium based on dual-cavity coupling are proposed. Summary of the invention

[0005] The embodiments of the present invention provide a dynamic non-reciprocal modulation method, system and storage medium based on dual-cavity coupling, so as to at least solve the problem that the related art is difficult to achieve effective non-reciprocal transmission of photons in a wide frequency range.

[0006] Non-reciprocity refers to the different responses of a system when photons enter the system from different directions, also known as non-reciprocal transmission of the light field. This non-reciprocity plays an important role in optical information processing systems, such as isolation. The use of non-reciprocal devices can effectively avoid the influence of reflected light fields from other devices or systems on the signal source.

[0007] According to one embodiment of the present invention, a dynamic non-reciprocal modulation method based on dual-cavity coupling is proposed, comprising:

[0008] Establish a dual-atom-dual-cavity waveguide QED system model;

[0009] Calculate the momentum equation of the two-atom-two-cavity waveguide QED system;

[0010] Calculate the transmittance expression of photons based on the momentum equation;

[0011] The non-reciprocal modulation of photon transmission is achieved by modulating the atomic frequency and / or the strength of the mutual coupling of the two cavities.

[0012] In an exemplary embodiment, the diatomic-dual-cavity waveguide QED system model is a system consisting of atom-cavity and cavity-cavity interactions and coupled with a waveguide, using a diatomic-dual-cavity structure in which the atomic frequency varies in the time domain.

[0013] In an exemplary embodiment, the calculation of the momentum equation of the diatomic-dual-cavity waveguide QED system comprises the steps of:

[0014] Construct an expression for the dynamic changes of diatomic frequencies;

[0015] Calculate the equivalent Hamiltonian of the two-atom-two-cavity waveguide QED system;

[0016] The momentum equation of photon motion in the two-atom-two-cavity waveguide QED system is calculated based on the equivalent Hamiltonian.

[0017] In an exemplary embodiment, the calculation of the equivalent Hamiltonian of the diatomic-dual-cavity waveguide QED system comprises the steps of:

[0018] Calculate the equivalent Hamiltonian of the waveguide according to the group velocity of photons transmitted in the waveguide;

[0019] The equivalent Hamiltonian of the cavity is calculated based on the cavity frequency and the dissipation rate of the dual cavity;

[0020] Calculate the atomic fixed frequency equivalent Hamiltonian based on the atomic excited state operator and the atomic dissipation rate;

[0021] The equivalent Hamiltonian of the interaction between the waveguide and the cavity is calculated according to the coupling strength between the waveguide and the double cavity;

[0022] The equivalent Hamiltonian of the interaction between the two cavities is calculated based on the Bessel function of the amplitude and frequency of the atomic frequency variation part;

[0023] The equivalent Hamiltonian of the cavity-atom interaction is calculated based on the coupling strength between the cavity and the atom.

[0024] In an exemplary embodiment, the step of calculating the momentum equation of photon motion in a two-atom-two-cavity waveguide QED system according to the equivalent Hamiltonian comprises the following steps:

[0025] Calculate the eigenstates of the system in the single excitation sub-cavity-waveguide space;

[0026] The Schrödinger equation is constructed based on the equivalent Hamiltonian of the two-atom-two-cavity waveguide QED system, the photon frequency and the eigenstate of the system;

[0027] By solving the conventional Schrödinger equation, the momentum equation of photon motion in the two-atom-two-cavity waveguide QED system is obtained.

[0028] In an exemplary embodiment, the calculation of the transmittance expression of photons according to the momentum equation comprises the steps of:

[0029] When a single photon is incident from the left or right side of the waveguide with a wave vector, the amplitude expression of the photon is obtained;

[0030] When the photon reaches the coupling point between the cavity and the waveguide, the incident photon is transmitted or reflected in the waveguide according to the interaction between the waveguide and the dual cavity-dyatom;

[0031] The photon transmittance expression is calculated based on the momentum equation of the two-atom-two-cavity waveguide QED system and the photon amplitude expression.

[0032] In an exemplary embodiment, the non-reciprocal modulation of photon transmission is achieved by modulating the atomic frequency and / or the strength of the mutual coupling of the two cavities, comprising the steps of:

[0033] Calculate the atomic frequency influence function based on the relationship between atomic frequency and photon transmittance;

[0034] The non-reciprocal influence function of the double-cavity coupling intensity is calculated according to the photon non-reciprocal transmission degree corresponding to the intensity of the double-cavity mutual coupling;

[0035] Calculating a non-reciprocal modulation function based on an atomic frequency influence function and / or a non-reciprocal influence function of a dual-cavity coupling strength;

[0036] The non-reciprocal modulation of photon transmission is achieved by modulating the atomic frequency and / or the strength of the mutual coupling of the two cavities according to the non-reciprocal modulation function.

[0037] In an exemplary embodiment, the non-reciprocal modulation of photon transmission is achieved by modulating the atomic frequency and / or the strength of the mutual coupling of the dual cavities according to the non-reciprocal modulation function, comprising the steps of:

[0038] Calculate the target non-reciprocal transmission contrast and target transmittance of photons according to the non-reciprocity requirement of photon transmission;

[0039] The target non-reciprocal transmission contrast of photons and the atomic frequency and dual-cavity coupling strength corresponding to the target transmittance are calculated according to the non-reciprocal modulation function;

[0040] The atomic frequency and dual-cavity coupling strength in the dual-atom-dual-cavity waveguide QED system are adjusted to corresponding values ​​to achieve non-reciprocal modulation of photon transmission.

[0041] A computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute the above method.

[0042] According to another embodiment of the present invention, a dynamic non-reciprocal modulation system based on dual-cavity coupling is provided, comprising:

[0043] A two-atom-two-cavity waveguide QED system;

[0044] processor;

[0045] Memory;

[0046] as well as

[0047] One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, the programs causing the computer to perform the above method.

[0048] The dynamic non-reciprocity modulation method, system and storage medium based on dual-cavity coupling of the present invention have the following advantages:

[0049] (1) We construct a dynamic expression of the atomic frequency of the diatomic-dual-cavity waveguide QED system and use the equivalent Hamiltonian and Schrödinger equation to solve the transmittance and reflectivity expression of photons in the diatomic-dual-cavity waveguide QED system. Compared with the traditional single-photon transmission modulation method, we can accurately analyze the single-photon dynamic transmission characteristics of the diatomic-dual-cavity waveguide QED system based on time domain modulation.

[0050] (2) The photon transmittance expression is calculated based on the momentum equation of the dual-atom-dual-cavity waveguide QED system and the amplitude expression of the photon. Compared with the traditional technical solution of single-photon transmission modulation, it can effectively analyze the influence of atomic frequency time-domain modulation on the single-photon transmittance and reflectivity, and effectively realize single-photon transmission control based on atomic frequency time-domain modulation.

[0051] (3) By modulating the atomic frequency to change the coupling strength between the atom and the cavity, the position of the photon transmission and reflection extreme points can be controlled to achieve photon transmission regulation. Compared with the traditional single-photon transmission modulation technology, it can effectively realize non-reciprocal photon transmission that is still effective in a wide frequency range.

[0052] (4) According to the non-reciprocity requirements of photon transmission, the photon non-reciprocal transmission contrast and the photon transmittance are calculated, and the corresponding atomic frequency and dual-cavity coupling strength are modulated according to the non-reciprocal modulation function. Compared with the traditional single-photon transmission modulation technology, the photon transmission and reflection extreme points can be dynamically controlled to achieve dynamically modulated single-photon non-reciprocal transmission in a wide frequency range. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a flow chart of a dynamic non-reciprocal modulation method based on dual-cavity coupling according to an embodiment of the present invention;

[0054] Figure 2 This is a model diagram of a two-atom-two-cavity waveguide QED system;

[0055] Figure 3 is a flowchart of step S02 of an embodiment of the present invention;

[0056] Figure 4 is a flowchart of sub-step S022 of an embodiment of the present invention;

[0057] Figure 5 is a flowchart of sub-step S023 of an embodiment of the present invention;

[0058] Figure 6 is a flowchart of step S03 of an embodiment of the present invention;

[0059] Figure 7 is a flowchart of step S04 of an embodiment of the present invention;

[0060] Figure 8 is a flowchart of sub-step S044 of an embodiment of the present invention;

[0061] Fig. 9 It is a structural schematic diagram of a dynamic non-reciprocal modulation system based on dual-cavity coupling according to an embodiment of the present invention. DETAILED DESCRIPTION

[0062] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0063] A dynamic non-reciprocal modulation method based on dual-cavity coupling according to an embodiment of the present invention is shown in the flowchart as follows: Figure 1 As shown, the steps include:

[0064] Step S01, establishing a two-atom-two-cavity waveguide QED system model;

[0065] Step S02, calculating the momentum equation of the diatomic-dual-cavity waveguide QED system;

[0066] Step S03, calculating the transmittance expression of photons according to the momentum equation;

[0067] Step S04: realizing non-reciprocal modulation of photon transmission by modulating the atomic frequency and / or the strength of the mutual coupling of the dual cavities.

[0068] The dual-atom-dual-cavity-waveguide system model of the present invention is relatively close to the theoretical model of the actual waveguide QED and has a high application value. At the same time, the atomic frequency in this system can be dynamically adjusted, which provides a breakthrough method for controlling the transmittance and reflectivity of single photons and realizing dynamic adjustment of single-photon scattering of different frequencies. In addition, according to the non-reciprocity requirement of photon transmission, the photon non-reciprocal transmission contrast and the transmittance and reflectivity of the photons are calculated, and the corresponding atomic frequency and dual-cavity coupling strength are modulated according to the non-reciprocity modulation function, so that the photon transmittance and reflectivity extreme points can be dynamically adjusted to realize dynamically modulated single-photon non-reciprocal transmission in a wide frequency range, which provides a new idea for the development of optical quantum information.

[0069] In an exemplary embodiment, the diatomic-dual-cavity waveguide QED system model is a system consisting of an atom-cavity and cavity-cavity interaction and waveguide coupling, using a diatomic-dual-cavity structure in which the atomic frequency varies in the time domain. In this embodiment, the diatomic-dual-cavity waveguide QED system model is as follows: Figure 2 As shown, the diatomic-dual-cavity waveguide QED system model is a system consisting of atom-cavity and cavity-cavity interactions and coupled with a waveguide, using a diatomic-dual-cavity structure in which the atomic frequency changes in the time domain.

[0070] In an exemplary embodiment, the step S02, calculating the momentum equation of the diatomic-dual-cavity waveguide QED system, is as follows: Figure 3 As shown, the steps include:

[0071] Step S021, constructing an expression for dynamic changes in diatomic frequency;

[0072] Step S022, calculating the equivalent Hamiltonian of the diatomic-dual-cavity waveguide QED system;

[0073] Step S023, calculating the momentum equation of photon motion in the two-atom-two-cavity waveguide QED system according to the equivalent Hamiltonian.

[0074] In this embodiment, this model uses a two-atom-two-cavity structure in which the atomic frequency changes in the time domain, and the atomic frequency expression is:

[0075] ω e,j＝1,2 =ω 0 +η j cos(ν d,j t) (1)

[0076] Formula (1) includes the atomic frequency fixed part w 0 and the atomic frequency change part η j cos(v d,j t), where η j is the amplitude of the changing part, v d,jis the frequency of the changing part.

[0077] The cavity interacting with the two-level atom is coupled to one side of the single-mode waveguide. The coupling strengths of the two atoms and the cavity change with time, and their expressions are:

[0078] G j＝1,2 =g j J 0 (f j ) (2)

[0079] Among them, J 0 (f) is the zero-order Bessel function, gj is the coupling strength between the cavity and the atom,

[0080] In an exemplary embodiment, the step S022, calculating the equivalent Hamiltonian of the diatomic-dual-cavity waveguide QED system, is as follows: Figure 4 As shown, including:

[0081] Step S0221, calculating the equivalent Hamiltonian of the waveguide according to the group velocity of photons transmitted in the waveguide;

[0082] Step S0222, calculating the equivalent Hamiltonian of the cavity according to the frequency of the cavity and the dissipation rate of the dual cavities;

[0083] Step S0223, calculating the equivalent Hamiltonian of the atomic fixed frequency according to the atomic excited state operator and the atomic dissipation rate;

[0084] Step S0224, calculating the equivalent Hamiltonian of the interaction between the waveguide and the cavity according to the coupling strength between the waveguide and the dual cavity;

[0085] Step S0225, calculating the equivalent Hamiltonian of the interaction between the two cavities according to the Bessel function of the amplitude and frequency of the atomic frequency variation part;

[0086] Step S0226: Calculate the equivalent Hamiltonian of the interaction between the cavity and the atom according to the coupling strength between the cavity and the atom.

[0087] In this embodiment, in this system, the frequency of the atoms is constantly changing periodically. The equivalent Hamiltonian of the diatomic-dual-cavity waveguide QED system is calculated using the real-space method, which are:

[0088] The equivalent Hamiltonian of the waveguide is calculated according to the group velocity of photons transmitted in the waveguide, which is expressed as:

[0089]

[0090] Among them, H w represents the equivalent Hamiltonian of the waveguide, v gis the group velocity of photons traveling in the waveguide, are the boson creation (annihilation) operators of a left-moving light beam and a right-moving light beam at position x respectively.

[0091] The equivalent Hamiltonian of the cavity is calculated based on the cavity frequency and the dissipation rate of the dual cavity, which is expressed as:

[0092]

[0093] Among them, H c represents the equivalent Hamiltonian of the cavity, ω c is the cavity frequency, γ j / 2 is the dissipation rate of the cavity, is the atomic raising (lowering) operator.

[0094] Calculate the atomic fixed frequency w based on the atomic excited state operator and the atomic dissipation rate 0 The equivalent Hamiltonian is expressed as:

[0095]

[0096] Among them, H a is the fixed frequency w in the atomic frequency expression 0 The equivalent Hamiltonian of +，j ,σ -，j Represents a pair of frequencies ω 0 The creation and annihilation operator, γ e,j / 2 represents the dissipation rate of the atom.

[0097] The equivalent Hamiltonian of the interaction between the waveguide and the cavity is calculated based on the coupling strength between the waveguide and the double cavity, which is expressed as:

[0098]

[0099] Among them, H wc The equivalent Hamiltonian for the interaction between the waveguide and the cavity, V 1 ,V 2 is the coupling strength between the waveguide and the cavity, and the function δ(x) represents the coupling between the cavity and the atom and the waveguide at x.

[0100] The equivalent Hamiltonian of the interaction between the two cavities is calculated based on the Bessel function of the amplitude and frequency of the atomic frequency change part, which is expressed as:

[0101]

[0102] Among them, H cc is the equivalent Hamiltonian of the interaction between the two cavities.

[0103] The equivalent Hamiltonian of the interaction between the cavity and the atom is calculated according to the coupling strength between the cavity and the atom, which is expressed as:

[0104]

[0105] Among them, H ac The equivalent Hamiltonian for the interaction between the cavity and the atom, g j is the coupling strength between the double cavity and the atom.

[0106] In an exemplary embodiment, the step S023, calculating the momentum equation of photon motion in the diatomic-dual-cavity waveguide QED system according to the equivalent Hamiltonian, is as follows: Figure 5 As shown, including:

[0107] Step S0231, calculating the eigenstate of the system in the single excitation sub-cavity-waveguide space;

[0108] Step S0232, constructing the Schrödinger equation according to the equivalent Hamiltonian of the diatomic-dual-cavity waveguide QED system, the photon frequency and the eigenstate of the system;

[0109] Step S0233: Obtain the momentum equation of photon motion in the two-atom-two-cavity waveguide QED system by solving the conventional Schrödinger equation.

[0110] In this embodiment, the research object is a single photon, the excitation number of the system is conserved, and there is only one at a time. The eigenstate in the single excitation sub-cavity-waveguide space is expressed as:

[0111]

[0112] The Schrödinger equation is constructed based on the equivalent Hamiltonian of the two-atom-two-cavity waveguide QED system, the photon frequency and the eigenstate of the system, which is expressed as:

[0113]

[0114] Where H represents the equivalent Hamiltonian of the system and ω represents the photon frequency.

[0115] By solving the conventional Schrödinger equation, the momentum equation of photon motion in the two-atom-two-cavity waveguide QED system is obtained, which is expressed as:

[0116]

[0117] Among them, φ R (x) is the probability amplitude of the photon going to the right, φ L (x) is the probability amplitude of the photon going left, μ c,j represents the probability amplitude of photons in different optical cavities, μ e，j Represents the probability amplitude of a photon being in different excited states.

[0118] In an exemplary embodiment, the step S03, calculating the transmittance expression of the photon according to the momentum equation, the flow chart is as follows: Figure 6 As shown, including:

[0119] Step S031, a single photon is incident from the left or right side of the waveguide with a wave vector, and an amplitude expression of the photon is obtained;

[0120] Step S032, when the photon reaches the coupling point between the cavity and the waveguide, the incident photon is transmitted or reflected in the waveguide according to the interaction between the waveguide and the dual cavity-dual atom;

[0121] Step S033, calculating the photon transmittance expression according to the momentum equation of the two-atom-two-cavity waveguide QED system and the photon amplitude expression.

[0122] In this embodiment, the scattering behavior of a single photon is studied, and parameters such as the transmittance and reflectance of the photon need to be solved. Assuming that a single photon is incident from the left or right side of the M waveguide with a wave vector k, the photon amplitude expression can be written respectively, which is expressed as:

[0123]

[0124] Among them, the step function θ(x) is expressed as:

[0125]

[0126] The photon propagates freely from the left or right in the waveguide. When it reaches the point where the cavity and the waveguide are coupled (x = 0, x = x 0 ), due to the interaction between the waveguide and the dual cavity-diatom, the incident photon may be transmitted or reflected in the waveguide. Solve the expression of the transmittance t when the photon is incident from the left end and the transmittance t when the photon is incident from the right end. The expression of is:

[0127]

[0128]

[0129] in:

[0130] k j＝1,2 =(ω-ω c +iγ j / 2);

[0131] k e,j =(ω-ω 0 +iγ e,j / 2);

[0132]

[0133] In an exemplary embodiment, the step S04 is to realize non-reciprocal modulation of photon transmission by modulating the atomic frequency and / or the strength of the mutual coupling of the dual cavities, as shown in the flow chart. Figure 7 As shown, including:

[0134] Step S041, calculating the atomic frequency influence function according to the relationship between the atomic frequency and the photon transmittance;

[0135] Step S042, calculating the non-reciprocal influence function of the dual-cavity coupling strength according to the photon non-reciprocal transmission degree corresponding to the mutual coupling strength of the dual-cavity;

[0136] Step S043, calculating a non-reciprocal modulation function according to the atomic frequency influence function and / or the non-reciprocal influence function of the dual-cavity coupling strength;

[0137] Step S044: modulate the atomic frequency and / or the strength of the mutual coupling of the dual cavities according to the non-reciprocal modulation function to achieve non-reciprocal modulation of photon transmission.

[0138] In this embodiment, the atomic frequency influence function G(f) is obtained according to the expression of the transmittance t of the photon; and the atomic frequency influence function G(f) is obtained according to the inverse function of the expression of the transmittance t.

[0139] Adjust the strength of the mutual coupling between the two cavities. The transmission of the incident single photon will change accordingly, and the non-reciprocal properties will also be different. In order to more intuitively describe the non-reciprocal transmission characteristics of photons, the non-reciprocal transmission contrast T is introduced. iso The degree of non-reciprocal transmission of photons is characterized by the expression shown in the following formula.

[0140]

[0141] Where t is the transmittance when the photon is incident from the left end: is the transmittance when the photon is incident from the right end.

[0142] The strength of the mutual coupling between the two cavities is determined by training and simulation Values ​​are obtained to obtain different non-reciprocal transmission contrasts, and the non-reciprocal influence function of the dual-cavity coupling strength is obtained by training.

[0143] The non-reciprocal modulation function is calculated based on the atomic frequency influence function and / or the non-reciprocal influence function of the dual-cavity coupling strength. The non-reciprocal modulation function is calculated based on the positive correlation between the non-reciprocal modulation function and the atomic frequency influence function and / or the non-reciprocal influence function of the dual-cavity coupling strength. express.

[0144] A1 to A3 in Table A represent different implementations for calculating the non-reciprocal modulation function.

[0145] Table A Different implementations of calculating the non-reciprocal modulation function

[0146]

[0147]

[0148] In an exemplary embodiment, the step S044, modulating the atomic frequency and / or the strength of the mutual coupling of the dual cavities according to the non-reciprocal modulation function to achieve non-reciprocal modulation of photon transmission, is as shown in the flowchart. Figure 8 As shown, including:

[0149] Step S0441, calculating the target non-reciprocal transmission contrast and target transmittance of photons according to the non-reciprocity requirement of photon transmission;

[0150] Step S0442, calculating the target non-reciprocal transmission contrast of photons and the atomic frequency and dual-cavity coupling strength corresponding to the target transmittance according to the non-reciprocal modulation function;

[0151] Step S0443, adjusting the atomic frequency and the dual-cavity coupling strength in the dual-atom-dual-cavity waveguide QED system to corresponding values ​​to achieve non-reciprocal modulation of photon transmission.

[0152] In this embodiment, the non-reciprocity requirements for photon transmission are preset according to the application scenario of photon transmission (for example, high requirements for non-reciprocity of photon transmission in isolation devices in optical information processing systems) to obtain the target non-reciprocal transmission contrast of photons and the target transmittance of photons.

[0153] According to the non-reciprocal modulation function Calculate the target nonreciprocal transmission contrast of photons and the target transmittance of photons corresponding to the atomic frequency f a and the dual cavity coupling strength value

[0154] Tune the atomic frequency and the dual-cavity coupling strength in the dual-atom-dual-cavity waveguide QED system to the corresponding atomic frequency f a and the dual cavity coupling strength value This achieves non-reciprocal modulation of photon transmission.

[0155] Simulation experiments show that when the mutual coupling strength of the two cavities The coupling strength g between the two cavities and the waveguide 1 ,g 2 and the frequency dynamic parameter f of the atom 1 ,f 2 They are fixed at g 1 =g2 =10Γ and f 1 =f 2 =0, set x = π / 4. When Γ 1 =Γ 2 When , the transmittance of photons with frequencies Δ=±13Γ,±7.5Γ is close to 0, and the transmittance curve has four minimum values; when Γ 1 =Γ,Γ 2 =5Γ, the transmittance of photons with frequencies Δ=±13.7Γ,±7.2Γ is close to 0, and the transmittance curve has four minimum values; when x=π / 3,Γ 1 =Γ 2 When , the transmittance of photons with frequencies of Δ = ±13.7Γ, ±7.2Γ is close to 0, the transmittance curve has four minimum values, and the curve tends to be smoother.

[0156] By modulating the photon transmittance through the atomic frequency, the transmission and reflection of photons of different frequencies vary with f j＝1,2 By dynamically modulating the parameter f j＝1,2 The value of f 1 =f 2 = 0, the minimum transmittance of photons appears at Δ = ±13Γ, ±7.5Γ; when f 1 =f 2 =1.8, the minimum transmittance of photons appears at Δ=±7.2Γ,±1.6Γ; when f 1 =0,f 2 =1.8, the minimum transmittance of photons appears at Δ=±11.7Γ,±2.9Γ. By dynamically modulating the atomic frequency, the photon transmittance and reflectance are analyzed. j＝1,2 There is an important relationship, when f j＝1,2 When changing from 0-2.4, the transmittance of photons with a frequency within -10Γ<Δ<10Γ can be modulated to 0<t<1, which can control the photons in this frequency range to achieve total reflection or total transmission.

[0157] Simulating the photon coupling strength when two cavities are coupled to each other The effect of changes on the spectrum of photon transmittance. Through simulation, it is found that when That is, when there is no interaction between the two cavities, the minimum transmittance can reach 0; when When , the minimum transmittance rises to about 0.1; when When , the minimum value of transmittance further increases to above 0.25. At the same time, it is found that changing the mutual coupling strength of the cavity will change the minimum point of the photon. When , the minimum point is at Δ≈3.4Γ, and is close to 0; and when When Δ≈3.4Γ, the photon transmittance is close to the maximum value, and its value is t>0.9. Therefore, with the assistance of other dynamic parameters such as atomic frequency, the mutual coupling strength of the cavity can achieve total transmission and total reflection of photons of different frequencies, forming functions such as photon switching.

[0158] When photons are incident from two directions, the size and position of the minimum transmittance are different, and are closely related to the coupling strength of the two cavities. As J increases, the photon nonreciprocal transmission contrast increases first and then decreases. The non-reciprocal effect is most obvious when .

[0159] The non-reciprocity of photons plays an important role and has a theoretical basis for the future development of optical communications and current optical information processing technologies, such as existing microwave magnetic isolators and optical circulators at the single-photon level and quantum entanglement in quantum information science.

[0160] A computer-readable storage medium according to an embodiment of the present invention stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute the above method.

[0161] A dynamic non-reciprocal modulation system based on dual-cavity coupling according to an embodiment of the present invention, the structural schematic diagram is as follows Fig. 9 As shown, including:

[0162] A two-atom-two-cavity waveguide QED system;

[0163] processor;

[0164] Memory;

[0165] as well as

[0166] One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, the programs causing the computer to perform the above method.

[0167] The method according to the present invention described above can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or as a computer code that is originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded through a network and will be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a special-purpose processor or programmable or special-purpose hardware (such as an ASIC or FPGA). It is understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the processing shown here, the execution of the code converts the general-purpose computer into a special-purpose computer for executing the processing shown here.

[0168] Of course, those skilled in the art should realize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the scope of the present invention, any changes or modifications to the above embodiments will fall within the protection scope of the present invention.

Claims

1. A dynamic non-reciprocal modulation method based on dual-cavity coupling, characterized in that: include: Establish a dual-atom-dual-cavity waveguide QED system model; Calculate the momentum equation of the two-atom-two-cavity waveguide QED system; Calculate the transmittance expression of photons based on the momentum equation; The non-reciprocal modulation of photon transmission is achieved by modulating the atomic frequency and / or the strength of the mutual coupling of the two cavities.

2. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 1, characterized in that: The diatomic-dual-cavity waveguide QED system model is a system consisting of atom-cavity and cavity-cavity interactions and coupled with a waveguide, and uses a diatomic-dual-cavity structure in which the atomic frequency changes in the time domain.

3. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 2, characterized in that: The method for calculating the momentum equation of the waveguide QED system of the diatomic-dual cavity comprises the steps of: Construct an expression for the dynamic changes of diatomic frequencies; Calculate the equivalent Hamiltonian of the two-atom-two-cavity waveguide QED system; The momentum equation of photon motion in the two-atom-two-cavity waveguide QED system is calculated based on the equivalent Hamiltonian.

4. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 3 is characterized in that: The method for calculating the equivalent Hamiltonian of the diatomic-dual-cavity waveguide QED system comprises the following steps: Calculate the equivalent Hamiltonian of the waveguide according to the group velocity of photons transmitted in the waveguide; The equivalent Hamiltonian of the cavity is calculated based on the cavity frequency and the dissipation rate of the dual cavity; Calculate the atomic fixed frequency equivalent Hamiltonian based on the atomic excited state operator and the atomic dissipation rate; The equivalent Hamiltonian of the interaction between the waveguide and the cavity is calculated according to the coupling strength between the waveguide and the double cavity; The equivalent Hamiltonian of the interaction between the two cavities is calculated based on the Bessel function of the amplitude and frequency of the atomic frequency variation part; The equivalent Hamiltonian of the cavity-atom interaction is calculated based on the coupling strength between the cavity and the atom.

5. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 3, characterized in that: The method of calculating the momentum equation of photon motion in a two-atom-two-cavity waveguide QED system according to the equivalent Hamiltonian comprises the following steps: Calculate the eigenstates of the system in the single excitation sub-cavity-waveguide space; The Schrödinger equation is constructed based on the equivalent Hamiltonian of the two-atom-two-cavity waveguide QED system, the photon frequency and the eigenstate of the system; By solving the conventional Schrödinger equation, the momentum equation of photon motion in the two-atom-two-cavity waveguide QED system is obtained.

6. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 1, characterized in that: The method of calculating the transmittance expression of photons according to the momentum equation comprises the steps of: When a single photon is incident from the left or right side of the waveguide with a wave vector, the amplitude expression of the photon is obtained; When the photon reaches the coupling point between the cavity and the waveguide, the incident photon is transmitted or reflected in the waveguide according to the interaction between the waveguide and the dual cavity-dyatom; The photon transmittance expression is calculated based on the momentum equation of the two-atom-two-cavity waveguide QED system and the photon amplitude expression.

7. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 6, characterized in that: The method of realizing non-reciprocal modulation of photon transmission by modulating the atomic frequency and / or the strength of the mutual coupling of the two cavities comprises the following steps: Calculate the atomic frequency influence function based on the relationship between atomic frequency and photon transmittance; The non-reciprocal influence function of the double-cavity coupling intensity is calculated according to the photon non-reciprocal transmission degree corresponding to the intensity of the double-cavity mutual coupling; Calculating a non-reciprocal modulation function based on an atomic frequency influence function and / or a non-reciprocal influence function of a dual-cavity coupling strength; The non-reciprocal modulation of photon transmission is achieved by modulating the atomic frequency and / or the strength of the mutual coupling of the two cavities according to the non-reciprocal modulation function.

8. The dynamic non-reciprocal modulation method based on dual-cavity coupling according to claim 7, characterized in that: The method of realizing non-reciprocal modulation of photon transmission by modulating the atomic frequency and / or the strength of the mutual coupling of the dual cavities according to the non-reciprocal modulation function comprises the following steps: Calculate the target non-reciprocal transmission contrast and target transmittance of photons according to the non-reciprocity requirement of photon transmission; The target non-reciprocal transmission contrast of photons and the atomic frequency and dual-cavity coupling strength corresponding to the target transmittance are calculated according to the non-reciprocal modulation function; The atomic frequency and dual-cavity coupling strength in the dual-atom-dual-cavity waveguide QED system are adjusted to corresponding values ​​to achieve non-reciprocal modulation of photon transmission.

9. A computer-readable storage medium storing a computer program for electronic data exchange, wherein: The computer program enables a computer to execute the method according to any one of claims 1 to 8.

10. A dynamic non-reciprocal modulation system based on dual-cavity coupling, characterized in that include: A two-atom-two-cavity waveguide QED system; processor; Memory; as well as One or more programs, wherein the one or more programs are stored in a memory and configured to be executed by the processor, the programs causing the computer to execute the method according to any one of claims 1 to 8.

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