95,587 research outputs found
The Coherent Crooks Equality
This chapter reviews an information theoretic approach to deriving quantum
fluctuation theorems. When a thermal system is driven from equilibrium, random
quantities of work are required or produced: the Crooks equality is a classical
fluctuation theorem that quantifies the probabilities of these work
fluctuations. The framework summarised here generalises the Crooks equality to
the quantum regime by modeling not only the driven system but also the control
system and energy supply that enables the system to be driven. As is reasonably
common within the information theoretic approach but high unusual for
fluctuation theorems, this framework explicitly accounts for the energy
conservation using only time independent Hamiltonians. We focus on explicating
a key result derived by Johan {\AA}berg: a Crooks-like equality for when the
energy supply is allowed to exist in a superposition of energy eigenstates
states.Comment: 11 pages, 3 figures; Chapter for the book "Thermodynamics in the
Quantum Regime - Recent Progress and Outlook", eds. F. Binder, L. A. Correa,
C. Gogolin, J. Anders and G. Adess
Electroweak Splitting Functions and High Energy Showering
We derive the electroweak (EW) collinear splitting functions for the Standard
Model, including the massive fermions, gauge bosons and the Higgs boson. We
first present the splitting functions in the limit of unbroken SU(2)xU(1) and
discuss their general features in the collinear and soft-collinear regimes. We
then systematically incorporate EW symmetry breaking (EWSB), which leads to the
emergence of additional "ultra-collinear" splitting phenomena and naive
violations of the Goldstone-boson Equivalence Theorem. We suggest a
particularly convenient choice of non-covariant gauge (dubbed "Goldstone
Equivalence Gauge") that disentangles the effects of Goldstone bosons and gauge
fields in the presence of EWSB, and allows trivial book-keeping of leading
power corrections in the VEV. We implement a comprehensive, practical EW
showering scheme based on these splitting functions using a Sudakov evolution
formalism. Novel features in the implementation include a complete accounting
of ultra-collinear effects, matching between shower and decay, kinematic
back-reaction corrections in multi-stage showers, and mixed-state evolution of
neutral bosons (gamma/Z/h) using density-matrices. We employ the EW showering
formalism to study a number of important physical processes at O(1-10 TeV)
energies. They include (a) electroweak partons in the initial state as the
basis for vector-boson-fusion; (b) the emergence of "weak jets" such as those
initiated by transverse gauge bosons, with individual splitting probabilities
as large as O(30%); (c) EW showers initiated by top quarks, including Higgs
bosons in the final state; (d) the occurrence of O(1) interference effects
within EW showers involving the neutral bosons; and (e) EW corrections to new
physics processes, as illustrated by production of a heavy vector boson (W')
and the subsequent showering of its decay products.Comment: 67 pages, 12 figures; v2, published in JHEP, some expanded
discussions and other minor revision
Consciousness, cognition, and the hierarchy of context: extending the global neuronal workspace model
We adapt an information theory analysis of interacting cognitive biological and social modules to the problem of the global neuronal workspace, the new standard neuroscience paradigm for consciousness. Tunable punctuation emerges in a natural way, suggesting the possibility of fitting appropriate phase transition power law, and away from transition, generalized Onsager relation expressions, to observational data on conscious reaction. The development can be extended in a straightforward manner to include psychosocial stress, culture, or other cognitive modules which constitute a structured, embedding hierarchy of contextual constraints acting at a slower rate than neuronal function itself. This produces a 'biopsychosociocultural' model of individual consciousness that, while otherwise quite close to the standard treatment, meets compelling philosophical and other objections to brain-only descriptions
Transfer Learning for OCRopus Model Training on Early Printed Books
A method is presented that significantly reduces the character error rates
for OCR text obtained from OCRopus models trained on early printed books when
only small amounts of diplomatic transcriptions are available. This is achieved
by building from already existing models during training instead of starting
from scratch. To overcome the discrepancies between the set of characters of
the pretrained model and the additional ground truth the OCRopus code is
adapted to allow for alphabet expansion or reduction. The character set is now
capable of flexibly adding and deleting characters from the pretrained alphabet
when an existing model is loaded. For our experiments we use a self-trained
mixed model on early Latin prints and the two standard OCRopus models on modern
English and German Fraktur texts. The evaluation on seven early printed books
showed that training from the Latin mixed model reduces the average amount of
errors by 43% and 26%, respectively compared to training from scratch with 60
and 150 lines of ground truth, respectively. Furthermore, it is shown that even
building from mixed models trained on data unrelated to the newly added
training and test data can lead to significantly improved recognition results
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