Autonomous conversion of information to work in quantum dots

With a class of quantum heat engines which consists of two-energy-eigenstate systems undergoing, respectively, quantum adiabatic processes and energy exchanges with heat baths at different stages of a cycle, we are able to clarify some important aspects of the second law of thermodynamics. The quantum heat engines also offer a practical way, as an alternative to Szilard's engine, to physically realise Maxwell's daemon. While respecting the second law on the average, they are ...

The inverse current in coupled (ICC) quantum transport, where one induced current opposes all thermodynamic forces of a system, is a highly counter-intuitive transport phenomenon. Using an exactly solvable model of strongly-coupled quantum dots, we present thermodynamic description of ICC in energy and spin-induced particle currents, with potential applications towards unconventional and autonomous nanoscale thermoelectric generators. Our analysis reveals the connection betwe...

We propose and analyze a possible implementation of Maxwell's demon based on a single-electron pump. We show that measurements of the charge states of the pump and feedback control of the gate voltages lead to a net flow of electrons against the bias voltage ideally with no work done on the system by the gate control. The information obtained in the measurements converts thermal fluctuations into free energy. We derive the conditions on the detector back-action and measuremen...

In this article, we introduce two kinds of Fluctuation Theorems (FT) containing information for autonomous Maxwell's demon-assisted machines. Using Jensen's Inequality, we obtain Landauer's principle formulation of the second law for the whole process of the machine. Finally we make use of our results to analyze a new information device. \pacs{05.70.Ln, 05.40.-a, 89.70.Cf}

It is nearly 150 years since Maxwell challenged the validity of the second law of thermodynamics by imagining a tiny creature who could sort the molecules of a gas in such a way that would decrease entropy without exerting any work. The demon has been discussed largely using thought experiments, but it has recently become possible to exert control over nanoscale systems, just as Maxwell imagined, and the status of the second law has become a more practical matter, raising the...

In order to describe quantum heat engines, here we systematically study isothermal and isochoric processes for quantum thermodynamic cycles. Based on these results the quantum versions of both the Carnot heat engine and the Otto heat engine are defined without ambiguities. We also study the properties of quantum Carnot and Otto heat engines in comparison with their classical counterparts. Relations and mappings between these two quantum heat engines are also investigated by c...

This chapter provides an overview of the methods and results for quantum thermodynamic experiments with single-electron devices. The experiments with a single-electron box on Jarzynski equality and Crooks relation, two-temperature fluctuation relations, and Maxwell's demon performed over the past few years are reviewed here. We further review the first experimental realization of an autonomous Maxwell's demon using a single-electron box as the demon.

It is generally accepted, following Landauer and Bennett, that the process of measurement involves no minimum entropy cost, but the erasure of information in resetting the memory register of a computer to zero requires dissipating heat into the environment. This thesis has been challenged recently in a two-part article by Earman and Norton. I review some relevant observations in the thermodynamics of computation and argue that Earman and Norton are mistaken: there is in princ...

We use continuous weak measurements of a driven superconducting qubit to experimentally study the information dynamics of a quantum Maxwell's demon. We show how information gained by a demon who can track single quantum trajectories of the qubit can be converted into work using quantum coherent feedback. We verify the validity of a quantum fluctuation theorem with feedback by utilizing information obtained along single trajectories. We demonstrate, in particular, that quantum...

The long-standing paradigm of Maxwell's demon is till nowadays a frequently investigated issue, which still provides interesting insights into basic physical questions. Considering a single-electron transistor, where we implement a Maxwell demon by a piecewise-constant feedback protocol, we investigate quantum implications of the Maxwell demon. To this end, we harness a dynamical coarse-graining method, which provides a convenient and accurate description of the system dynami...