31 citations · 111 across the 13 of their papers we have counts for
14 papers
Realizations of free actions via their fixed point algebras
Kay Schwieger, Stefan Wagner
Let be a compact group, let be a unital C-algebra, and let be a free C-dynamical system, in the sense of Ellwood, with fixed point alg…
An Atiyah Sequence for Noncommutative Principal Bundles
Kay Schwieger, Stefan Wagner
We present a derivation-based Atiyah sequence for noncommutative principal bundles. Along the way we treat the problem of deciding when a given -automorphism on the quantum bas…
Lifting spectral triples to noncommutative principal bundles
Kay Schwieger, Stefan Wagner
Given a free action of a compact Lie group on a unital C*-algebra and a spectral triple on the corresponding fixed point algebra , we present a sys…
A model for calorimetric measurements in an open quantum system
Brecht Donvil, Paolo Muratore-Ginanneschi, Jukka P. Pekola +1
We investigate the experimental setup proposed in [New J. Phys., 15, 115006 (2013)] for calorimetric measurements of thermodynamic indicators in an open quantum system. As theoreti…
Noncommutative Coverings of Quantum Tori
Kay Schwieger, Stefan Wagner
We introduce a framework for coverings of noncommutative spaces. Moreover, we study noncommutative coverings of irrational quantum tori and characterize all such coverings that are…
An application of Pontryagin's principle to Brownian particle engineered equilibration
Paolo Muratore-Ginanneschi, Kay Schwieger
We present a stylized model of controlled equilibration of a small system in a fluctuating environment. We derive the equations governing the optimal control steering \emph{in fini…
Part III, Free Actions of Compact Quantum Groups on C*-Algebras
Kay Schwieger, Stefan Wagner
We study and classify free actions of compact quantum groups on unital C*-algebras in terms of generalized factor systems. Moreover, we use these factor systems to show that all fi…
Fluctuation Relation for Qubit-Calorimetry
Antti Kupiainen, Paolo Muratore-Ginanneschi, Jukka Pekola +1
Motivated by proposed thermometry measurement on an open quantum system, we present a simple model of an externally driven qubit interacting with a finite sized, fermion environmen…
Part II, Free Actions of Compact Groups on C*-Algebras
Kay Schwieger, Stefan Wagner
We study a simple subclass of free actions of non-Abelian groups on unital C*-algebras, namely cleft actions. These are characterized by the fact that the associated noncommutative…
Part I, Free Actions of Compact Abelian Groups on C*-Algebras
Kay Schwieger, Stefan Wagner
We study free and compact group actions on unital C*-algebras. In particular, we provide a complete classification theory of these actions for compact Abelian groups and explain it…
On the efficiency of heat engines at the micro-scale and below
Paolo Muratore-Ginanneschi, Kay Schwieger
We investigate the thermodynamic efficiency of sub-micro-scale heat engines operating under the conditions described by over-damped stochastic thermodynamics. We prove that at maxi…
On how nanomechanical systems can minimize dissipation
Paolo Muratore-Ginanneschi, Kay Schwieger
Information processing machines at the nanoscales are unavoidably affected by thermal fluctuations. Efficient design requires understanding how nanomachines can operate at minimal…
Diagonal Couplings of Quantum Markov Chains
Burkhard Kümmerer, Kay Schwieger
In this article we extend the coupling method from classical probability theory to quantum Markov chains on atomic von Neumann algebras. In particular, we establish a coupling ineq…
Ergodic Properties of Quantum Birth and Death Chains
David Bücher, Andreas Gärtner, Burkhard Kümmerer +3
We study a class of quantum Markov processes that, on the one hand, is inspired by the micromaser experiment in quantum optics and, on the other hand, by classical birth and death…