399 research outputs found
Maximally epistemic interpretations of the quantum state and contextuality
We examine the relationship between quantum contextuality (in both the
standard Kochen-Specker sense and in the generalised sense proposed by
Spekkens) and models of quantum theory in which the quantum state is maximally
epistemic. We find that preparation noncontextual models must be maximally
epistemic, and these in turn must be Kochen-Specker noncontextual. This implies
that the Kochen-Specker theorem is sufficient to establish both the
impossibility of maximally epistemic models and the impossibility of
preparation noncontextual models. The implication from preparation
noncontextual to maximally epistemic then also yields a proof of Bell's theorem
from an EPR-like argument.Comment: v1: 4 pages, revTeX4.1, some overlap with arXiv:1207.7192. v2:
Changes in response to referees including revised proof of theorem 1, more
rigorous discussion of measure theoretic assumptions and extra introductory
materia
Fluctuation Theorem with Information Exchange: Role of Correlations in Stochastic Thermodynamics
We establish the fluctuation theorem in the presence of information exchange
between a nonequilibrium system and other degrees of freedom such as an
observer and a feedback controller, where the amount of information exchange is
added to the entropy production. The resulting generalized second law sets the
fundamental limit of energy dissipation and energy cost during the information
exchange. Our results apply not only to feedback-controlled processes but also
to a much broader class of information exchanges, and provides a unified
framework of nonequilibrium thermodynamics of measurement and feedback control.Comment: To appear in PR
Opening up the Quantum Three-Box Problem with Undetectable Measurements
One of the most striking features of quantum mechanics is the profound effect
exerted by measurements alone. Sophisticated quantum control is now available
in several experimental systems, exposing discrepancies between quantum and
classical mechanics whenever measurement induces disturbance of the
interrogated system. In practice, such discrepancies may frequently be
explained as the back-action required by quantum mechanics adding quantum noise
to a classical signal. Here we implement the 'three-box' quantum game of
Aharonov and Vaidman in which quantum measurements add no detectable noise to a
classical signal, by utilising state-of-the-art control and measurement of the
nitrogen vacancy centre in diamond.
Quantum and classical mechanics then make contradictory predictions for the
same experimental procedure, however classical observers cannot invoke
measurement-induced disturbance to explain this discrepancy. We quantify the
residual disturbance of our measurements and obtain data that rule out any
classical model by > 7.8 standard deviations, allowing us for the first time to
exclude the property of macroscopic state-definiteness from our system. Our
experiment is then equivalent to a Kochen-Spekker test of quantum
non-contextuality that successfully addresses the measurement detectability
loophole
A note on the Landauer principle in quantum statistical mechanics
The Landauer principle asserts that the energy cost of erasure of one bit of
information by the action of a thermal reservoir in equilibrium at temperature
T is never less than . We discuss Landauer's principle for quantum
statistical models describing a finite level quantum system S coupled to an
infinitely extended thermal reservoir R. Using Araki's perturbation theory of
KMS states and the Avron-Elgart adiabatic theorem we prove, under a natural
ergodicity assumption on the joint system S+R, that Landauer's bound saturates
for adiabatically switched interactions. The recent work of Reeb and Wolf on
the subject is discussed and compared
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Energy and eventhood: the infrastructural set piece
‘Energy and Eventhood’ considers the relationship between infrastructure and the cinematic set piece. It proposes a working definition of the set piece as a distinctly (and perhaps excessively) effortful passage or sequence, and reflects on the tendency for narrative films to incorporate infrastructural sites and structures—such as bridges, dams and pipelines—into such set pieces. A number of writers on infrastructure, as both a cultural phenomenon and a representational object, have noted the aesthetic challenge of rendering it as visible and locatable; this article examines how that difficulty becomes manifest in the infrastructural set piece. It takes as its case studies Unstoppable (2010) and Night Moves (2013), two films noted for their distinctive rhythmic expressiveness, and each one deploying the convention of the set piece in ways which exemplify and reflect on the resistance of infrastructure to narrative containment
Detectability, Invasiveness and the Quantum Three Box Paradox
Quantum pre- and post-selection (PPS) paradoxes occur when counterfactual
inferences are made about different measurements that might have been
performed, between two measurements that are actually performed. The 3 box
paradox is the paradigm example of such a paradox, where a ball is placed in
one of three boxes and it is inferred that it would have been found, with
certainty, both in box 1 and in box 2 had either box been opened on their own.
Precisely what is at stake in PPS paradoxes has been unclear, and classical
models have been suggested which are supposed to mimic the essential features
of the problem. We show that the essential difference between the classical and
quantum pre- and post-selection effects lies in the fact that for a quantum PPS
paradox to occur the intervening measurement, had it been performed, would need
to be invasive but non-detectable. This invasiveness is required even for null
result measurements. While some quasi-classical features (such as
non-contextuality and macrorealism) are compatible with PPS paradoxes, it seems
no fully classical model of the 3 box paradox is possible.Comment: 16 pages, no figure
Integrated and Open Interpreter Education: The Open Educational Resource Reader and Workbook for Interpreters
https://digitalcommons.wou.edu/facbooks/1001/thumbnail.jp
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