2,811 research outputs found
Epistemic Logic for Communication Chains
The paper considers epistemic properties of linear communication chains. It
describes a sound and complete logical system that, in addition to the standard
axioms of S5 in a multi-modal language, contains two non-trivial axioms that
capture the linear structure of communication chains.Comment: 7 pages, Contributed talk at TARK 2013 (arXiv:1310.6382)
http://www.tark.or
Complementary expressions for the entropy-from-work theorem
We establish an expression of the entropy-from-work theorem that is
complementary to the one originally proposed in [P. Talkner, P. Hanggi and M.
Morillo, arXiv:0707.2307]. In the original expression the final energy is fixed
whereas in the present expression the initial energy is fixed.Comment: 2 Page
Information complexity is computable
The information complexity of a function is the minimum amount of
information Alice and Bob need to exchange to compute the function . In this
paper we provide an algorithm for approximating the information complexity of
an arbitrary function to within any additive error , thus
resolving an open question as to whether information complexity is computable.
In the process, we give the first explicit upper bound on the rate of
convergence of the information complexity of when restricted to -bit
protocols to the (unrestricted) information complexity of .Comment: 30 page
Comment on "Quantum key distribution for d-level systems with generalized Bell states" [Phys. Rev. A 65, 052331 (2002)]
In the paper [Phys. Rev. A 65, 052331(2002)], an entanglement-based quantum
key distribution protocol for d-level systems was proposed. However, in this
Comment, it is shown that this protocol is insecure for a special attack
strategy.Comment: 4 pages, 4 figure
Device-Independent Relativistic Quantum Bit Commitment
We examine the possibility of device-independent relativistic quantum bit
commitment. We note the potential threat of {\it location attacks}, in which
the behaviour of untrusted devices used in relativistic quantum cryptography
depends on their space-time location. We describe relativistic quantum bit
commitment schemes that are immune to these attacks, and show that these
schemes offer device-independent security against hypothetical post-quantum
adversaries subject only to the no-signalling principle. We compare a
relativistic classical bit commitment scheme with similar features, and note
some possible advantages of the quantum schemes
Effects of depolarizing quantum channels on BB84 and SARG04 quantum cryptography protocols
We report experimental studies on the effect of the depolarizing quantum
channel on weak-pulse BB84 and SARG04 quantum cryptography. The experimental
results show that, in real world conditions in which channel depolarization
cannot be ignored, BB84 should perform better than SARG04.Comment: 4 pages, 4 figure
State based model of long-term potentiation and synaptic tagging and capture
Recent data indicate that plasticity protocols have not only synapse-specific but also more widespread effects. In particular, in synaptic tagging and capture (STC), tagged synapses can capture plasticity-related proteins, synthesized in response to strong stimulation of other synapses. This leads to long-lasting modification of only weakly stimulated synapses. Here we present a biophysical model of synaptic plasticity in the hippocampus that incorporates several key results from experiments on STC. The model specifies a set of physical states in which a synapse can exist, together with transition rates that are affected by high- and low-frequency stimulation protocols. In contrast to most standard plasticity models, the model exhibits both early- and late-phase LTP/D, de-potentiation, and STC. As such, it provides a useful starting point for further theoretical work on the role of STC in learning and memory
Security bounds for continuous variables quantum key distribution
Security bounds for key distribution protocols using coherent and squeezed
states and homodyne measurements are presented. These bounds refer to (i)
general attacks and (ii) collective attacks where Eve interacts individually
with the sent states, but delays her measurement until the end of the
reconciliation process. For the case of a lossy line and coherent states, it is
first proven that a secure key distribution is possible up to 1.9 dB of losses.
For the second scenario, the security bounds are the same as for the completely
incoherent attack.Comment: See also F. Grosshans, quant-ph/040714
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