We clarify the role of non-adiabatic effects in quantum pumping for a spin-boson system. When we sinusoidally control the temperatures of two reservoirs with | $\pi /2$ | phase difference, we find that the pumping current strongly depends on the initial condition, and thus, the current deviates from that predicted by the adiabatic treatment. We also analytically obtain the contribution of non-adiabatic effects in the pumping current proportional to | $\Omega ^3$ |⁠, where | $\Omega$ | is the angular frequency of the temperature control. The validity of the analytic expression is verified by our numerical calculation. Moreover, we extend the steady heat fluctuation theorem to the case for slowly modulated temperatures and large transferred energies.We clarify the role of non-adiabatic effects in quantum pumping for a spin-boson system. When we sinusoidally control the temperatures of two reservoirs with |$\pi /2$| phase difference, we find that the pumping current strongly depends on the initial condition, and thus, the current deviates from that predicted by the adiabatic treatment. We also analytically obtain the contribution of non-adiabatic effects in the pumping current proportional to |$\Omega ^3$|⁠, where |$\Omega$| is the angular frequency of the temperature control. The validity of the analytic expression is verified by our numerical calculation. Moreover, we extend the steady heat fluctuation theorem to the case for slowly modulated temperatures and large transferred energies.

arXiv:1408.5182Progress of Theoretical and Experimental PhysicsNov 17, 201420 citations

Propagation and Parametric Amplification in Four-Wave Mixing Processes: Intramolecular Coupling and High-Order Effects

José Luis Paz, Patricio J. Espinoza-Montero, Marcos Loroño +7 more

A strong pump-power dependence of the four-wave mixing (FWM) signal for an aqueous solution of Malachite green is reported. The characteristics of the pump-power dependence of the nonlinear signal are reproduced by a theoretical model based on the coupling between pump-probe, considering signal fields and propagation effects. The effect of the intramolecular coupling on the nonlinear intensity of the FWM signal is studied using a model molecule consisting of two-coupled harmonic curves of electronic energies with minima displaced in energy and nuclear positions. Two-vibrational states are considered while including non-adiabatic effects for the two-state model. Moreover, the coupling among the field components, as well as the propagation effects, are studied by considering a constant pump-intensity. Our calculation scheme, considering both the intramolecular coupling effects in the description of the molecular structure and the effects produced by the propagation of the FWM signal along the optical length, allows the exponential dependence of the latter, as the intensity of the pumping beam increases. Our treatments do not require the inclusion of other non-resonant processes outside the RWA approximation, due to the consideration of an adiabatic basis.A strong pump-power dependence of the four-wave mixing (FWM) signal for an aqueous solution of Malachite green is reported. The characteristics of the pump-power dependence of the nonlinear signal are reproduced by a theoretical model based on the coupling between pump-probe, considering signal fields and propagation effects. The effect of the intramolecular coupling on the nonlinear intensity of the FWM signal is studied using a model molecule consisting of two-coupled harmonic curves of electronic energies with minima displaced in energy and nuclear positions. Two-vibrational states are considered while including non-adiabatic effects for the two-state model. Moreover, the coupling among the field components, as well as the propagation effects, are studied by considering a constant pump-intensity. Our calculation scheme, considering both the intramolecular coupling effects in the description of the molecular structure and the effects produced by the propagation of the FWM signal along the optical length, allows the exponential dependence of the latter, as the intensity of the pumping beam increases. Our treatments do not require the inclusion of other non-resonant processes outside the RWA approximation, due to the consideration of an adiabatic basis.

SymmetryFeb 2, 20222 citations

Fluctuation Relations For Adiabatic Quantum Pumping

Yuki Hino, Hisao Hayakawa

arXiv:1908.10597Aug 28, 20191 citation

Engineering topological quantum state transfer via quantum metric

Ming-Zhu Xiao, Hai-Tao Ding, Dan-Wei Zhang

Topological pumping has attracted great attention in topological physics and is highly valuable in the realization of robust quantum state transfer (QST). However, speeding up the topological QST under the requirement of adiabatic evolutions remains challenging. In this work, we propose a geometric adiabatic criterion with an effective quantum metric that characterizes non-adiabatic transitions during evolutions via the quantum metric, minimal energy gap and cycle time. Using two generalized Su–Schrieffer–Heeger models, we systematically validate our adiabatic criterion in optimizing topological pumping paths for transferring single-site states and two-site entangled states, respectively. With numerical simulations, we show that by designing pumping paths for minimizing the effective quantum metric, the fidelity and speed of the QST can be significantly improved. Our works provides a general framework for high-fidelity topological QST via quantum metric optimization.Topological pumping has attracted great attention in topological physics and is highly valuable in the realization of robust quantum state transfer (QST). However, speeding up the topological QST under the requirement of adiabatic evolutions remains challenging. In this work, we propose a geometric adiabatic criterion with an effective quantum metric that characterizes non-adiabatic transitions during evolutions via the quantum metric, minimal energy gap and cycle time. Using two generalized Su–Schrieffer–Heeger models, we systematically validate our adiabatic criterion in optimizing topological pumping paths for transferring single-site states and two-site entangled states, respectively. With numerical simulations, we show that by designing pumping paths for minimizing the effective quantum metric, the fidelity and speed of the QST can be significantly improved. Our works provides a general framework for high-fidelity topological QST via quantum metric optimization.

Quantum Review LettersJan 1, 20260 citations

Transport in adiabatic quantum pumps

Gian Michele Graf, Alexander Elgart, Lorenzo A. Sadun +1 more

International Congress on Mathematical Physics (ICMP)Mar 1, 20060 citations

We clarify the role of non-adiabatic effects in quantum pumping for a spin-boson system. When we sinusoidally control the temperatures of two reservoirs with |

\pi /2

| phase difference, we find that the pumping current strongly depends on the initial condition, and thus, the current deviates from that predicted by the adiabatic treatment. We also analytically obtain the contribution of non-adiabatic effects in the pumping current proportional to |

\Omega ^3

|⁠, where |

\Omega

| is the angular frequency of the temperature control. The validity of the analytic expression is verified by our numerical calculation. Moreover, we extend the steady heat fluctuation theorem to the case for slowly modulated temperatures and large transferred energies.