Coherent control via interplay between driving field and two-body interaction in a double well

Abstract

We investigate interplay between external field and interatomic interaction and its applications to coherent control of quantum tunneling for two repulsive bosons confined in a high-frequency driven double well. A full solution of the system is generated analytically as a coherent non-Floquet state by using the Floquet states as a set of complete bases. It is demonstrated that the photon resonance of interaction leads to translation of the Floquet level-crossing points, and the non-resonant interaction causes avoided crossing of partial levels. In the non-Floquet states, the bosons beyond the crossing points slowly vary their populations, and the resonant (non-resonant) interactions enhance (decrease) the tunneling rate of the paired particles. Three different kinds of the coherent destructions of tunneling (CDT) at the crossing, avoided-crossing and uncrossing points, and the corresponding stationary-like states, are illustrated. The analytical results are numerically confirmed and perfect agreements are found. Based on the results, an useful scheme of quantum tunneling switch between stationary-like states is presented.

Coherent control of quasi-degenerate stationary-like states via multiple resonances

“…It is known that these Floquet states are the SLSs with variable probability amplitudes and invariant populations 31 , 32 . Quantum population transfer of any particle cannot occur in a single Floquet state , but it can occur in a linear superposition state of the Floquet states.…”

“…In a system of double-well trapped few particles, any one of the above-mentioned motional states corresponds to a certain atomic distribution, which can be expanded in terms of Fock basis. If the probability amplitude of the system being in any Fock state is time-dependent and the corresponding probability is a constant, we call the quantum state the stationary-like (or quasistationary) state (SLS) 31 , 32 . A SLS with invariant population may be a single Floquet state or a superposition of Floquet states.…”

Coherent control of spin tunneling in a spin-orbit coupled bosonic triple well

“…This will result in the quasienergies E 3 = E 5 = − α/2 and E 4 = E 6 = α/2, which means that the new quasienergy degeneracy occurs. To our knowledge, the degeneracy of energy levels generally implies quantum decoherence, so it will lead to the intriguing phenomenon of quantum tunneling, for instance, the selective coherent destruction of tunneling (SCDT) takes place at the degeneracy (crossing) point of the partial energy levels [34][35][36] and coherent destruction of tunneling (CDT) occurs at the collapse (crossing) point of all energy levels [37,38]. As an example, we set the parameters γ = 0.5, ω = 50, Ω = 100, ν = 1, and (a) ε 2 = 5.1356ω, (b) ε 2 = 2ω to plot the quasienergy spectra with quasienergy as a function of the driving parameter ε 1 /ω, as in figure 1(a)-(b), respectively.…”

Transparent control of three-body selective destruction of tunneling via unusual states

“…In order to study tunneling dynamics, we have to consider the coherent superposition of the Floquet states. When the superposition states do not satisfy the well-known definition of the Flouqet state, we call them the non-Flouqet states [29,46]. The superposition principle of quantum mechanics indicates that the Floquet states (6) constitutes a set of complete bases in a four-dimensional Hilbert space [47,48], and the non-Floquet states can be constructed by the linear superposition of the Floquet states.…”