2,950 research outputs found
Mitigating smart card fault injection with link-time code rewriting: a feasibility study
We present a feasibility study to protect smart card software against fault-injection attacks by means of binary code rewriting. We implemented a range of protection techniques in a link-time rewriter and evaluate and discuss the obtained coverage, the associated overhead and engineering effort, as well as its practical usability
Efficient Quantum Computation using Coherent States
Universal quantum computation using optical coherent states is studied. A
teleportation scheme for a coherent-state qubit is developed and applied to
gate operations. This scheme is shown to be robust to detection inefficiency.Comment: 6 pages, 5 figures, extended and modified (in print, PRA
A Two-Step Quantum Direct Communication Protocol Using Einstein-Podolsky-Rosen Pair Block
A protocol for quantum secure direct communication using blocks of EPR pairs
is proposed. A set of ordered EPR pairs is used as a data block for sending
secret message directly. The ordered EPR set is divided into two particle
sequences, a checking sequence and a message-coding sequence. After
transmitting the checking sequence, the two parties of communication check
eavesdropping by measuring a fraction of particles randomly chosen, with random
choice of two sets of measuring bases. After insuring the security of the
quantum channel, the sender, Alice encodes the secret message directly on the
message-coding sequence and send them to Bob. By combining the checking and
message-coding sequences together, Bob is able to read out the encoded messages
directly. The scheme is secure because an eavesdropper cannot get both
sequences simultaneously. We also discuss issues in a noisy channel.Comment: 8 pages and 2 figures. To appear in Phys Rev
Development and manufacture of printable next-generation gel polymer ionic liquid electrolyte for Zn/MnO\u3csub\u3e2\u3c/sub\u3e batteries
While much energy storage research focuses on the performance of individual components, such as the electrolyte or a single electrode, few investigate the electrochemical system as a whole. This research reports on the design, composition, and performance of a Zn/MnO2 battery as affected by the manufacturing method and next-generation gel polymer electrolyte composed of the ionic liquid [BMIM][Otf], ZnOtf salt, and PVDF-HFP polymer binder. Materials and manufacturing tests are discussed with a focus on water concentration, surface features as produced by printing processes, and the effect of including a gel polymer phase. Cells produced for this research generated open circuit voltages from 1.0 to 1.3 V. A dry [BMIM][Otf] electrolyte was found to have 87.3 ppm of H2O, while an electrolyte produced in ambient conditions contained 12400 ppm of H2O. Cells produced in a dry, Ar environment had an average discharge capacity of 0.0137 mAh/cm2, while one produced in an ambient environment exhibited a discharge capacity at 0.05 mAh/cm2. Surface features varied significantly by printing method, where a doctor blade produced the most consistent features. The preliminary results herein suggest that water, surface roughness, and the gel polymer play important roles in affecting the performance of printed energy storage
Computation using Noise-based Logic: Efficient String Verification over a Slow Communication Channel
Utilizing the hyperspace of noise-based logic, we show two string
verification methods with low communication complexity. One of them is based on
continuum noise-based logic. The other one utilizes noise-based logic with
random telegraph signals where a mathematical analysis of the error probability
is also given. The last operation can also be interpreted as computing
universal hash functions with noise-based logic and using them for string
comparison. To find out with 10^-25 error probability that two strings with
arbitrary length are different (this value is similar to the error probability
of an idealistic gate in today's computer) Alice and Bob need to compare only
83 bits of the noise-based hyperspace.Comment: Accepted for publication in European Journal of Physics B (November
10, 2010
Long-term trends in tropical cyclone tracks around Korea and Japan in late summer and early fall
This study investigates long-term trends in tropical cyclones (TCs) over the extratropical western North Pacific (WNP) over a period of 35 years (1982-2016). The area analyzed extended across 30-45 degrees N and 120-150 degrees E, including the regions of Korea and Japan that were seriously affected by TCs. The northward migration of TCs over the WNP to the mid-latitudes showed a sharp increase in early fall. In addition, the duration of TCs over the WNP that migrated northwards showed an increase, specifically in early to mid-September. Therefore, more recently, TC tracks have been observed to significantly extend into the mid-latitudes. The recent northward extension of TC tracks over the WNP in early fall was observed to be associated with changes in environmental conditions that were favorable for TC activities, including an increase in sea surface temperature (SST), decrease in vertical wind shear, expansion of subtropical highs, strong easterly steering winds, and an increase in relative vorticity. In contrast, northward migrations of TCs to Korea and Japan showed a decline in late August, because of the presence of unfavorable environmental conditions for TC activities. These changes in environmental conditions, such as SST and vertical wind shear, can be partially associated with the Pacific decadal oscillation
Entanglement preparation using symmetric multiports
We investigate the entanglement produced by a multi-path interferometer that
is composed of two symmetric multiports, with phase shifts applied to the
output of the first multiport. Particular attention is paid to the case when we
have a single photon entering the interferometer. For this situation we derive
a simple condition that characterize the types of entanglement that one can
generate. We then show how one can use the results from the single photon case
to determine what kinds of multi-photon entangled states one can prepare using
the interferometer.Comment: 6 pages, 2 figures, accepted for publication in European Journal of
Physics
Entanglement preparation using symmetric multiports
We investigate the entanglement produced by a multi-path interferometer that
is composed of two symmetric multiports, with phase shifts applied to the
output of the first multiport. Particular attention is paid to the case when we
have a single photon entering the interferometer. For this situation we derive
a simple condition that characterize the types of entanglement that one can
generate. We then show how one can use the results from the single photon case
to determine what kinds of multi-photon entangled states one can prepare using
the interferometer.Comment: 6 pages, 2 figures, accepted for publication in European Journal of
Physics
Robustness of Decoherence-Free Subspaces for Quantum Computation
It was shown recently [D.A. Lidar et al., Phys. Rev. Lett. 81, 2594 (1998)]
that within the framework of the semigroup Markovian master equation,
decoherence-free (DF) subspaces exist which are stable to first order in time
to a perturbation. Here this result is extended to the non-Markovian regime and
generalized. In particular, it is shown that within both the semigroup and the
non-Markovian operator sum representation, DF subspaces are stable to all
orders in time to a symmetry-breaking perturbation. DF subspaces are thus ideal
for quantum memory applications. For quantum computation, however, the
stability result does not extend beyond the first order. Thus, to perform
robust quantum computation in DF subspaces, they must be supplemented with
quantum error correcting codes.Comment: 16 pages, no figures. Several changes, including a clarification of
the derivation of the Lindblad equation from the operator sum representation.
To appear in Phys. Rev
Strong subadditivity inequality for quantum entropies and four-particle entanglement
Strong subadditivity inequality for a three-particle composite system is an
important inequality in quantum information theory which can be studied via a
four-particle entangled state. We use two three-level atoms in
configuration interacting with a two-mode cavity and the Raman adiabatic
passage technique for the production of the four-particle entangled state.
Using this four-particle entanglement, we study for the first time various
aspects of the strong subadditivity inequality.Comment: 5 pages, 3 figures, RevTeX4, submitted to PR
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