Spectral Magnetization Ratchets with Discrete Time Quantum Walks
| Autor: | Arindam Mallick, P. Kaczynska, Sergej Flach, Mikhail V. Fistul |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
Quantum Physics Statistical Mechanics (cond-mat.stat-mech) Operator (physics) FOS: Physical sciences Parity (physics) Ratchet effect 01 natural sciences Symmetry (physics) 010305 fluids & plasmas Correlation function Quantum mechanics 0103 physical sciences Quantum walk Symmetry breaking 010306 general physics Quantum Physics (quant-ph) Quantum Condensed Matter - Statistical Mechanics |
| DOI: | 10.48550/arxiv.2001.03868 |
| Popis: | We predict and theoretically study in detail the ratchet effect for the spectral magnetization of periodic discrete time quantum walks (DTQWs) --- a repetition of a sequence of $m$ different DTQWs. These generalized DTQWs are achieved by varying the corresponding coin operator parameters periodically with discrete time. We consider periods $m=1,2,3$. The dynamics of $m$-periodic DTQWs is characterized by a two-band dispersion relation $\omega^{(m)}_{\pm}(k)$, where $k$ is the wave vector. We identify a generalized parity symmetry of $m$-periodic DTQWs. The symmetry can be broken for $m=2,3$ by proper choices of the coin operator parameters. The obtained symmetry breaking results in a ratchet effect, i.e. the appearance of a nonzero spectral magnetization $M_s(\omega)$. This ratchet effect can be observed in the framework of continuous quantum measurements of the time-dependent correlation function of periodic DTQWs. Comment: 11 pages, 9 figures. Comments are welcome |
| Databáze: | OpenAIRE |
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