440 research outputs found
Twenty years of distributed port-Hamiltonian systems:A literature review
The port-Hamiltonian (pH) theory for distributed parameter systems has developed greatly in the past two decades. The theory has been successfully extended from finite-dimensional to infinite-dimensional systems through a lot of research efforts. This article collects the different research studies carried out for distributed pH systems. We classify over a hundred and fifty studies based on different research focuses ranging from modeling, discretization, control and theoretical foundations. This literature review highlights the wide applicability of the pH systems theory to complex systems with multi-physical domains using the same tools and language. We also supplement this article with a bibliographical database including all papers reviewed in this paper classified in their respective groups
Strong coupling corrections in quantum thermodynamics
Quantum systems strongly coupled to many-body systems equilibrate to the
reduced state of a global thermal state, deviating from the local thermal state
of the system as it occurs in the weak-coupling limit. Taking this insight as a
starting point, we study the thermodynamics of systems strongly coupled to
thermal baths. First, we provide strong-coupling corrections to the second law
applicable to general systems in three of its different readings: As a
statement of maximal extractable work, on heat dissipation, and bound to the
Carnot efficiency. These corrections become relevant for small quantum systems
and always vanish in first order in the interaction strength. We then move to
the question of power of heat engines, obtaining a bound on the power
enhancement due to strong coupling. Our results are exemplified on the
paradigmatic situation of non-Markovian quantum Brownian motion.Comment: 20 pages, 3 figures, version two is substantially revised and
contains new result
Double Exchange Models: Self Consistent Renormalisation
We propose a scheme for constructing classical spin Hamiltonians from Hunds
coupled spin-fermion models in the limit J_H/t \to \infinity. The strong
coupling between fermions and the core spins requires self-consistent
calculation of the effective exchange in the model, either in the presence of
inhomogeneities or with changing temperature. In this paper we establish the
formalism and discuss results mainly on the ``clean'' double exchange model,
with self consistently renormalised couplings, and compare our results with
exact simulations. Our method allows access to system sizes much beyond the
reach of exact simulations, and we can study transport and optical properties
of the model without artificial broadening. The method discussed here forms the
foundation of our papers Phys. Rev. Lett. 91, 246602 (2003), and Phys. Rev.
Lett. 92, 126602 (2004).Comment: 11 pages revtex. Final version, to appear in EPJ
Canonical quantization of superconducting circuits
226 p.Los circuitos superconductores han surgido como una de las implementaciones fÃsicas más prometedorasen tecnologÃas cuánticas, fusionando la fÃsica, la ingenierÃa y las matemáticas. Esta tesis expone modeloshamiltonianos matemáticamente consistentes y precisos para describir redes superconductoras idealesformadas por un número arbitrario de elementos concentrados y distribuidos como condensadores,inductores, uniones de Josephson, giradores, y lÃneas de transmisión. Aunque son ideales, hemosdemostrado que estos modelos que están basados en las leyes de Kirchhoff, son finitos y no presentanproblemas de divergencias, disipando malentendidos de la literatura previa. Finalmente se describe unaextensión de la teorÃa estándar para cuantizar circuitos que incluyen elementos ideales no recÃprocos deforma sistemática, y se allana el camino para su extensión a giradores y circuladores dependientes defrecuencia
Energy-based Modeling and Control of Interactive Aerial Robots:A Geometric Port-Hamiltonian Approach
The role of quantum information in thermodynamics --- a topical review
This topical review article gives an overview of the interplay between
quantum information theory and thermodynamics of quantum systems. We focus on
several trending topics including the foundations of statistical mechanics,
resource theories, entanglement in thermodynamic settings, fluctuation theorems
and thermal machines. This is not a comprehensive review of the diverse field
of quantum thermodynamics; rather, it is a convenient entry point for the
thermo-curious information theorist. Furthermore this review should facilitate
the unification and understanding of different interdisciplinary approaches
emerging in research groups around the world.Comment: published version. 34 pages, 6 figure
Irreversibility, coherence and quantum fluctuation theorems
Irreversible processes have long been the focus of much attention in physics, forming cornerstones of thermodynamics and the foundations of quantum mechanics (principally the measurement problem). Recent interest in the marriage of these two fields has laid bare the partial inadequacy of definitions of thermodynamic work in a quantum context. Its problems are fundamental to quantum mechanics, in that projective measurements irreversibly destroy coherence in a state. To attempt to resolve this incompatibility, we begin with a deterministic quantum work process that adequately generalises the Newtonian framework for deterministic work processes. In doing so, we uncover a structure that has strong links to an old problem in probability theory on the decomposability of random variables. Crucially, we define coherent work as a state and Hamiltonian pair, sidestepping the measurement problem. We then look to fluctuation theorems which detail the thermodynamic irreversibility, and further develop a recent framework to show how our coherent work state appears just as Newtonian work appears in Crooks’ fluctuation theorem – providing an infinite hierarchy of correction terms. To round this off, we discuss the implications of incorporating additional observables, both commuting and complementary, on work processes and thermodynamics.Open Acces
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