7,774 research outputs found
Fluctuation theorems in presence of information gain and feedback
In this study, we rederive the fluctuation theorems in presence of feedback,
by assuming the known Jarzynski equality and detailed fluctuation theorems. We
first reproduce the already known work theorems for a classical system, and
then extend the treatment to the other classical theorems. For deriving the
extended quantum fluctuation theorems, we have considered open systems. No
assumption is made on the nature of environment and the strength of system-bath
coupling. However, it is assumed that the measurement process involves
classical errors.Comment: 8 pages, 1 figur
The emotional valence of subliminal priming effects perception of facial expressions
We investigated, in young healthy subjects, how the affective content of subliminally
presented priming images and their specific visual attributes impacted conscious
perception of facial expressions. The priming images were broadly categorised as
aggressive, pleasant, or neutral and further subcategorised by the presence of a face and
by the centricity (egocentric or allocentric vantage-point) of the image content. Subjects
responded to the emotion portrayed in a pixelated target-face by indicating via key-press
if the expression was angry or neutral. Priming images containing a face compared to
those not containing a face significantly impaired performance on neutral or angry targetface
evaluation. Recognition of angry target-face expressions was selectively impaired by
pleasant prime images which contained a face. For egocentric primes, recognition of
neutral target-face expressions was significantly better than of angry expressions. Our
results suggest that, first, the affective primacy hypothesis which predicts that affective
information can be accessed automatically, preceding conscious cognition, holds true in
subliminal priming only when the priming image contains a face. Second, egocentric
primes interfere with the perception of angry target-face expressions suggesting that this
vantage-point, directly relevant to the viewer, perhaps engages processes involved in
action preparation which may weaken the priority of affect processing.Accepted manuscrip
Entanglement and coherence in quantum state merging
Understanding the resource consumption in distributed scenarios is one of the
main goals of quantum information theory. A prominent example for such a
scenario is the task of quantum state merging where two parties aim to merge
their parts of a tripartite quantum state. In standard quantum state merging,
entanglement is considered as an expensive resource, while local quantum
operations can be performed at no additional cost. However, recent developments
show that some local operations could be more expensive than others: it is
reasonable to distinguish between local incoherent operations and local
operations which can create coherence. This idea leads us to the task of
incoherent quantum state merging, where one of the parties has free access to
local incoherent operations only. In this case the resources of the process are
quantified by pairs of entanglement and coherence. Here, we develop tools for
studying this process, and apply them to several relevant scenarios. While
quantum state merging can lead to a gain of entanglement, our results imply
that no merging procedure can gain entanglement and coherence at the same time.
We also provide a general lower bound on the entanglement-coherence sum, and
show that the bound is tight for all pure states. Our results also lead to an
incoherent version of Schumacher compression: in this case the compression rate
is equal to the von Neumann entropy of the diagonal elements of the
corresponding quantum state.Comment: 9 pages, 1 figure. Lemma 5 in Appendix D of the previous version was
not correct. This did not affect the results of the main tex
Fluctuation relations for heat engines in time-periodic steady states
A fluctuation relation for heat engines (FRHE) has been derived recently. In
the beginning, the system is in contact with the cooler bath. The system is
then coupled to the hotter bath and external parameters are changed cyclically,
eventually bringing the system back to its initial state, once the coupling
with the hot bath is switched off. In this work, we lift the condition of
initial thermal equilibrium and derive a new fluctuation relation for the
central system (heat engine) being in a time-periodic steady state (TPSS).
Carnot's inequality for classical thermodynamics follows as a direct
consequence of this fluctuation theorem even in TPSS. For the special cases of
the absence of hot bath and no extraction of work, we obtain the integral
fluctuation theorem for total entropy and the generalized exchange fluctuation
theorem, respectively. Recently microsized heat engines have been realized
experimentally in the TPSS. We numerically simulate the same model and verify
our proposed theorems.Comment: 9 page
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