16 research outputs found
DFT-inspired methods for quantum thermodynamics
In the framework of quantum thermodynamics, we propose a method to
quantitatively describe thermodynamic quantities for out-of-equilibrium
interacting many-body systems. The method is articulated in various
approximation protocols which allow to achieve increasing levels of accuracy,
it is relatively simple to implement even for medium and large number of
interactive particles, and uses tools and concepts from density functional
theory. We test the method on the driven Hubbard dimer at half filling, and
compare exact and approximate results. We show that the proposed method
reproduces the average quantum work to high accuracy: for a very large region
of parameter space (which cuts across all dynamical regimes) estimates are
within 10% of the exact results
Ancilla-assisted measurement of quantum work
We review the use of an external auxiliary detector for measuring the full
distribution of the work performed on or extracted from a quantum system during
a unitary thermodynamic process. We first illustrate two paradigmatic schemes
that allow one to measure the work distribution: a Ramsey technique to measure
the characteristic function and a positive operator valued measure (POVM)
scheme to directly measure the work probability distribution. Then, we show
that these two ideas can be understood in a unified framework for assessing
work fluctuations through a generic quantum detector and describe two protocols
that are able to yield complementary information. This allows us also to
highlight how quantum work is affected by the presence of coherences in the
system's initial state. Finally, we describe physical implementations and
experimental realisations of the first two schemes.Comment: Published version. As a chapter of: F. Binder, L. A. Correa, C.
Gogolin, J. Anders, and G. Adesso (eds.), "Thermodynamics in the quantum
regime - Recent Progress and Outlook", (Springer International Publishing