2022年1月
Flowequation approach to quantum systems driven by an amplitudemodulated timeperiodic force
Physical Review A
 ,
 ,
 巻
 105
 号
 1
 記述言語
 掲載種別
 研究論文（学術雑誌）
 DOI
 10.1103/PhysRevA.105.012203
We apply the method of flow equations to describe quantum systems subject to a timeperiodic drive with a timedependent envelope. The driven Hamiltonian is expressed in terms of its constituent Fourier harmonics with amplitudes that may vary as a function of time. The time evolution of the system is described in terms of the phaseindependent effective Hamiltonian and the complementary micromotion operator that are generated by deriving and solving the flow equations. These equations implement the evolution with respect to an auxiliary flow variable and facilitate a gradual transformation of the quasienergy matrix (the Kamiltonian) into a blockdiagonal form in the extended space. We construct a flow generator that prevents the appearance of additional Fourier harmonics during the flow, thus enabling implementation of the flow in a computer algebra system. Automated generation of otherwise cumbersome highfrequency expansions (for both the effective Hamiltonian and the micromotion) to an arbitrary order thus becomes straightforward for driven Hamiltonians expressible in terms of a finite algebra of Hermitian operators. We give several specific examples and discuss the possibility to extend the treatment to cover rapid modulation of the envelope.
 リンク情報
 ID情報

 DOI : 10.1103/PhysRevA.105.012203
 ISSN : 24699926
 eISSN : 24699934
 SCOPUS ID : 85122596307