منابع مشابه
Quantum Ratchets
We investigate quantum Brownian motion in adiabatically rocked ratchet systems. Above a crossover temperature Tc tunneling events are rare, yet they already substantially enhance the classical particle current. Below Tc, quantum tunneling prevails and the classical predictions grossly underestimate the transport. Upon approaching T 0 the quantum current exhibits a tunneling induced reversal, ...
متن کاملQuantum Ratchets
The concept of thermal ratchets is extended to the system governed by quantum mechanics. We study a tight-binding model with an asymmetric periodic potential contacting with a heat bath under an external oscillating field as a specific example of quantum ratchet. Dynamics of a density operator of this system is studied numerically by using the quantum Liouville equation. Finite net current is f...
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We discuss the relation between dimensional reduction in quantum field theories at finite temperature and a familiar quantummechanical phenomenon that quantum effects become negligible at high temperatures. Fermi and Bose fields are compared in this respect. We show that decoupling of fermions from the dimensionally reduced theory can be related to the non-existence of classical statistics for ...
متن کاملUnderdamped quantum ratchets
We investigate the quantum ratchet effect under the influence of weak dissipation which we treat within a Floquet-Markov master equation approach. A ratchet current emerges when all relevant symmetries are violated. Using time-reversal symmetric driving we predict a purely dissipation-induced quantum ratchet current. This directed quantum transport results from bath-induced superpositions of no...
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Water environments with temperatures up to and above boiling are commonly found in association with geothermal activity. At temperatures above 60 degrees C, only bacteria are found. Bacteria with temperature optima over the range 65 degrees to 105 degrees C have been obtained in pure culture and are the object of many research projects. The upper temperature limit for life in liquid water has n...
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ژورنال
عنوان ژورنال: Physica E: Low-dimensional Systems and Nanostructures
سال: 2005
ISSN: 1386-9477
DOI: 10.1016/j.physe.2005.05.043