1,179,046 research outputs found
Handbook of cleaning requirements, procedures, and verification techniques for oxygen systems
Oxygen system cleaning specifications have been drawn from twenty-three government and industrial sources. Cleaning processes for meeting these specifications and recommended postcleaning inspection procedures are compiled in handbook. Microfiche supplement of pertinent pages of listed references is included
Disorder, Metal-Insulator crossover and Phase diagram in high-Tc cuprates
We have studied the influence of disorder induced by electron irradiation on
the normal state resistivities of optimally and underdoped YBa2CuOx
single crystals, using pulsed magnetic fields up to 60T to completely restore
the normal state. We evidence that point defect disorder induces low T upturns
of rho(T) which saturate in some cases at low T in large applied fields as
would be expected for a Kondo-like magnetic response. Moreover the magnitude of
the upturns is related to the residual resistivity, that is to the
concentration of defects and/or their nanoscale morphology. These upturns are
found quantitatively identical to those reported in lower Tc cuprates, which
establishes the importance of disorder in these supposedly pure compounds. We
therefore propose a realistic phase diagram of the cuprates, including
disorder, in which the superconducting state might reach the antiferromagnetic
phase in the clean limit.Comment: version 2 with minor change
Single hole dynamics in the Kondo Necklace and Bilayer Heisenberg models on a square lattice
We study single hole dynamics in the bilayer Heisenberg and Kondo Necklace
models. Those models exhibit a magnetic order-disorder quantum phase transition
as a function of the interlayer coupling J_perp. At strong coupling in the
disordered phase, both models have a single-hole dispersion relation with band
maximum at p = (\pi,\pi) and an effective mass at this p-point which scales as
the hopping matrix element t. In the Kondo Necklace model, we show that the
effective mass at p = (\pi,\pi) remains finite for all considered values of
J_perp such that the strong coupling features of the dispersion relation are
apparent down to weak coupling. In contrast, in the bilayer Heisenberg model,
the effective mass diverges at a finite value of J_perp. This divergence of the
effective mass is unrelated to the magnetic quantum phase transition and at
weak coupling the dispersion relation maps onto that of a single hole doped in
a planar antiferromagnet with band maximum at p = (\pi/2,\pi/2). We equally
study the behavior of the quasiparticle residue in the vicinity of the magnetic
quantum phase transition both for a mobile and static hole. In contrast to
analytical approaches, our numerical results do not unambiguously support the
fact that the quasiparticle residue of the static hole vanishes in the vicinity
of the critical point. The above results are obtained with a generalized
version of the loop algorithm to include single hole dynamics on lattice sizes
up to 20 X 20.Comment: 12 pages, 13 Fig
Multiplpe Choice Minority Game With Different Publicly Known Histories
In the standard Minority Game, players use historical minority choices as the
sole public information to pick one out of the two alternatives. However,
publishing historical minority choices is not the only way to present global
system information to players when more than two alternatives are available.
Thus, it is instructive to study the dynamics and cooperative behaviors of this
extended game as a function of the global information provided. We numerically
find that although the system dynamics depends on the kind of public
information given to the players, the degree of cooperation follows the same
trend as that of the standard Minority Game. We also explain most of our
findings by the crowd-anticrowd theory.Comment: Extensively revised, to appear in New J Phys, 7 pages with 4 figure
No Superluminal Signaling Implies Unconditionally Secure Bit Commitment
Bit commitment (BC) is an important cryptographic primitive for an agent to
convince a mutually mistrustful party that she has already made a binding
choice of 0 or 1 but only to reveal her choice at a later time. Ideally, a BC
protocol should be simple, reliable, easy to implement using existing
technologies, and most importantly unconditionally secure in the sense that its
security is based on an information-theoretic proof rather than computational
complexity assumption or the existence of a trustworthy arbitrator. Here we
report such a provably secure scheme involving only one-way classical
communications whose unconditional security is based on no superluminal
signaling (NSS). Our scheme is inspired by the earlier works by Kent, who
proposed two impractical relativistic protocols whose unconditional securities
are yet to be established as well as several provably unconditionally secure
protocols which rely on both quantum mechanics and NSS. Our scheme is
conceptually simple and shows for the first time that quantum communication is
not needed to achieve unconditional security for BC. Moreover, with purely
classical communications, our scheme is practical and easy to implement with
existing telecom technologies. This completes the cycle of study of
unconditionally secure bit commitment based on known physical laws.Comment: This paper has been withdrawn by the authors due to a crucial
oversight on an earlier work by A. Ken
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