Landau-Zener-Stückelberg(LZS)interference has drawn renewed attention to quantum information processing research because it is not only an effective tool for characterizing two-level quantum systems but also a po...Landau-Zener-Stückelberg(LZS)interference has drawn renewed attention to quantum information processing research because it is not only an effective tool for characterizing two-level quantum systems but also a powerful approach to manipulate quantum states.Superconducting quantum circuits,due to their versatile tunability and degrees of control,are ideal platforms for studying LZS interference phenomena.We use a superconducting Xmon qubit to study LZS interference by parametrically modulating the qubit transition frequency nonlinearly.For dc flux biasing of the qubit slightly far away from the optimal flux point,the qubit excited state population shows an interference pattern that is very similar to the standard LZS interference in linear regime,except that all bands shift towards lower frequencies when increasing the rf modulation amplitude.For dc flux biasing close to the optimal flux point,the negative sidebands and the positive sidebands behave differently,resulting in an asymmetric interference pattern.The experimental results are also in good agreement with our analytical and numerical simulations.展开更多
We propose a scheme to implement quantum information transfer between Cooper-pair boxes(CPBs)in a circuit quantum electrodynamic(QED)system with Landau–Zener tunneling.The system consists of two CPB qubits and a one-...We propose a scheme to implement quantum information transfer between Cooper-pair boxes(CPBs)in a circuit quantum electrodynamic(QED)system with Landau–Zener tunneling.The system consists of two CPB qubits and a one-dimensional transmission line resonator(TLR).By analytically solving the eigenequation and numerically calculating the transition probability,the results show the quantum state transfer from one qubit to another via a fast adiabatic passage.The coupling mechanism is robust against decoherence effects.展开更多
The Landau equation is studied for hard potential with-2≤γ≤1.Under a perturbation setting,a unique global solution of the Cauchy problem to the Landau equation is established in a critical Sobolev space H_(x)^(d)L_...The Landau equation is studied for hard potential with-2≤γ≤1.Under a perturbation setting,a unique global solution of the Cauchy problem to the Landau equation is established in a critical Sobolev space H_(x)^(d)L_(v)^(2)(d>3/2),which extends the results of[11]in the torus domain to the whole space R_(x)^(3).Here we utilize the pseudo-differential calculus to derive our desired result.展开更多
In this paper,we prove that there exists a unique local solution for the Cauchy problem of a system of the incompressible Navier-Stokes-Landau-Lifshitz equations with the Dzyaloshinskii-Moriya interaction and V-flow t...In this paper,we prove that there exists a unique local solution for the Cauchy problem of a system of the incompressible Navier-Stokes-Landau-Lifshitz equations with the Dzyaloshinskii-Moriya interaction and V-flow term inR^(2) and R^(3).Our methods rely upon approximating the system with a perturbed parabolic system and parallel transport.展开更多
Recently a new type of experiment, i.e., Bloch oscillations of ultracold atoms in honeycomb optical potential,realized Landau–Zener transition in the vicinity of Dirac point in 2D optical lattice. We show that the sl...Recently a new type of experiment, i.e., Bloch oscillations of ultracold atoms in honeycomb optical potential,realized Landau–Zener transition in the vicinity of Dirac point in 2D optical lattice. We show that the slope of Dirac cone is related to the transition probability of Landau–Zener transition. Therefore, it provides a new tool to directly detect the energy spectrum in the vicinity of Dirac point. Moreover, we numerically demonstrate that our scheme is feasible and effective in a large range of the parameter of anisotropy.展开更多
We study the effect of Landau-Zener （LZ） tunneling caused by the varying sweeping rate of the external field, and solve the problem about the LZ tunneling rate among many levels. The LZ tunneling rate is essentially...We study the effect of Landau-Zener （LZ） tunneling caused by the varying sweeping rate of the external field, and solve the problem about the LZ tunneling rate among many levels. The LZ tunneling rate is essentially changed by the unsteady variation of the time-dependent sweeping field and is different from the steadily varying sweeping field, which makes the particles in lower states transit periodically to upper states within a finite time.展开更多
We study the Landau-Zener tunneling of a nonlinear two-level system by applying a periodic modulation on its energy bias. We find that the two levels are splitting at the zero points of the zero order Bessel function ...We study the Landau-Zener tunneling of a nonlinear two-level system by applying a periodic modulation on its energy bias. We find that the two levels are splitting at the zero points of the zero order Bessel function for high- frequency modulation. Moreover, we obtain the effective coupling constant between two levels at the zero points of the zero order Bessel function by calculating the final tunneling probability at these points. It seems that the effective coupling constant can be regarded as the approximation of the higher order Bessel function at these points. For the low-frequency modulation, we find that the final tunneling probability is a function of the interaction strength. For the weak inter-level coupling case, we find that the final tunneling probability is more disordered as the interaction strength becomes larger.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11874065the Key R&D Program of Guangdong Province under Grant No 2018B030326001+3 种基金the Guangdong Innovative and Entrepreneurial Research Team Program under Grant No 2016ZT06D348the Natural Science Foundation of Guangdong Province under Grant No 2017B030308003the Natural Science Foundation of Hunan Province under Grant No 2018JJ1031the Science,Technology and Innovation Commission of Shenzhen Municipality under Grant Nos ZDSYS20170303165926217,JCYJ20170412152620376 and KYTDPT20181011104202253
文摘Landau-Zener-Stückelberg(LZS)interference has drawn renewed attention to quantum information processing research because it is not only an effective tool for characterizing two-level quantum systems but also a powerful approach to manipulate quantum states.Superconducting quantum circuits,due to their versatile tunability and degrees of control,are ideal platforms for studying LZS interference phenomena.We use a superconducting Xmon qubit to study LZS interference by parametrically modulating the qubit transition frequency nonlinearly.For dc flux biasing of the qubit slightly far away from the optimal flux point,the qubit excited state population shows an interference pattern that is very similar to the standard LZS interference in linear regime,except that all bands shift towards lower frequencies when increasing the rf modulation amplitude.For dc flux biasing close to the optimal flux point,the negative sidebands and the positive sidebands behave differently,resulting in an asymmetric interference pattern.The experimental results are also in good agreement with our analytical and numerical simulations.
基金by the National Natural Science Foundation of China under Grant Nos 61134008(Key Program)and 11074307.
文摘We propose a scheme to implement quantum information transfer between Cooper-pair boxes(CPBs)in a circuit quantum electrodynamic(QED)system with Landau–Zener tunneling.The system consists of two CPB qubits and a one-dimensional transmission line resonator(TLR).By analytically solving the eigenequation and numerically calculating the transition probability,the results show the quantum state transfer from one qubit to another via a fast adiabatic passage.The coupling mechanism is robust against decoherence effects.
文摘The Landau equation is studied for hard potential with-2≤γ≤1.Under a perturbation setting,a unique global solution of the Cauchy problem to the Landau equation is established in a critical Sobolev space H_(x)^(d)L_(v)^(2)(d>3/2),which extends the results of[11]in the torus domain to the whole space R_(x)^(3).Here we utilize the pseudo-differential calculus to derive our desired result.
文摘In this paper,we prove that there exists a unique local solution for the Cauchy problem of a system of the incompressible Navier-Stokes-Landau-Lifshitz equations with the Dzyaloshinskii-Moriya interaction and V-flow term inR^(2) and R^(3).Our methods rely upon approximating the system with a perturbed parabolic system and parallel transport.
基金Support from the Scientific Research Foundation of Graduate School of South China Normal University
文摘Recently a new type of experiment, i.e., Bloch oscillations of ultracold atoms in honeycomb optical potential,realized Landau–Zener transition in the vicinity of Dirac point in 2D optical lattice. We show that the slope of Dirac cone is related to the transition probability of Landau–Zener transition. Therefore, it provides a new tool to directly detect the energy spectrum in the vicinity of Dirac point. Moreover, we numerically demonstrate that our scheme is feasible and effective in a large range of the parameter of anisotropy.
基金Project supported by the National Natural Science Foundation of China (Grant No. 20804039)the Natural Science Foundation of Zhejiang Province of China (Grant No. Y4080300)
文摘We study the effect of Landau-Zener （LZ） tunneling caused by the varying sweeping rate of the external field, and solve the problem about the LZ tunneling rate among many levels. The LZ tunneling rate is essentially changed by the unsteady variation of the time-dependent sweeping field and is different from the steadily varying sweeping field, which makes the particles in lower states transit periodically to upper states within a finite time.
基金Project supported by the National Natural Science Foundation of China (Grant No 10875098)The Natural Science Foundation of Northwest Normal University (Grant No NWNU-KJCXGC 03-48,03-17)
文摘We study the Landau-Zener tunneling of a nonlinear two-level system by applying a periodic modulation on its energy bias. We find that the two levels are splitting at the zero points of the zero order Bessel function for high- frequency modulation. Moreover, we obtain the effective coupling constant between two levels at the zero points of the zero order Bessel function by calculating the final tunneling probability at these points. It seems that the effective coupling constant can be regarded as the approximation of the higher order Bessel function at these points. For the low-frequency modulation, we find that the final tunneling probability is a function of the interaction strength. For the weak inter-level coupling case, we find that the final tunneling probability is more disordered as the interaction strength becomes larger.
