1,248 research outputs found
On the Machian Origin of Inertia
We examine Sciama's inertia theory: we generalise it, by combining rotation
and expansion in one unique model, we find the angular speed of the Universe,
and we stress that the theory is zero-total-energy valued. We compare with
other theories of the same null energy background. We determine the numerical
value of a constant which appears in the Machian inertial force expression
devised by Graneau and Graneau[2], by introducing the above angular speed. We
point out that this last theory is not restricted to Newtonian physics as those
authors stated but is, in fact, compatible with other cosmological and
gravitational theories. An argument by Berry[7] is shown in order to "derive"
Brans-Dicke relation in the present context.Comment: 10 pages including front one. New version was accepted to publication
by Astrophysics and Space Scienc
Relations for classical communication capacity and entanglement capability of two-qubit operations
Bipartite operations underpin both classical communication and entanglement
generation. Using a superposition of classical messages, we show that the
capacity of a two-qubit operation for error-free entanglement-assisted
bidirectional classical communication can not exceed twice the entanglement
capability. In addition we show that any bipartite two-qubit operation can
increase the communication that may be performed using an ensemble by twice the
entanglement capability.Comment: 4 page
CALGreen: California Green Building Standards Code: Blog 3
CALGreen encourages local governments to go beyond statewide Energy Code regulations to achieve greater building energy efficiency and cost savings, all while providing the necessary resources to do so. The currently enforced version of CALGreen is the 2019 CALGreen code. Mandates and voluntary provisions in the 2022 CALGreen update will go into effect January 1, 2023.¹ If both the 2022 Energy Code and 2022 CALGreen mandatory and voluntary standards were to be adopted statewide, the carbon reductions would be equivalent to removing 8,000 fuel-powered cars off the road for the first year and 24,000 fuel-powered cars by the third year.² This means that 2022 is a critical year for local jurisdictions throughout California and the San Diego region to inform, educate, and implement opportunities that maximize energy savings, greenhouse gas emission reductions, and public health benefits.https://digital.sandiego.edu/npi-sdclimate/1019/thumbnail.jp
Misleading signatures of quantum chaos
The main signature of chaos in a quantum system is provided by spectral
statistical analysis of the nearest neighbor spacing distribution and the
spectral rigidity given by . It is shown that some standard
unfolding procedures, like local unfolding and Gaussian broadening, lead to a
spurious increase of the spectral rigidity that spoils the
relationship with the regular or chaotic motion of the system. This effect can
also be misinterpreted as Berry's saturation.Comment: 4 pages, 5 figures, submitted to Physical Review
Resonances and the thermonuclear reaction rate
We present an approximate analytic expression for thermonuclear reaction rate
of charged particles when the cross section contains a single narrow or wide
resonance described by a Breit-Wigner shape. The resulting expression is
uniformly valid as the effective energy and resonance energy coalesce. We use
our expressions to calculate the reaction rate for
C(p,)N.Comment: 4 pages, 1 figure, presented at the VIII International Conference on
Nucleus-Nucleus in Moscow (Russia) on June 17-21, 200
General Adiabatic Evolution with a Gap Condition
We consider the adiabatic regime of two parameters evolution semigroups
generated by linear operators that are analytic in time and satisfy the
following gap condition for all times: the spectrum of the generator consists
in finitely many isolated eigenvalues of finite algebraic multiplicity, away
from the rest of the spectrum. The restriction of the generator to the spectral
subspace corresponding to the distinguished eigenvalues is not assumed to be
diagonalizable. The presence of eigenilpotents in the spectral decomposition of
the generator forbids the evolution to follow the instantaneous eigenprojectors
of the generator in the adiabatic limit. Making use of superadiabatic
renormalization, we construct a different set of time-dependent projectors,
close to the instantaneous eigeprojectors of the generator in the adiabatic
limit, and an approximation of the evolution semigroup which intertwines
exactly between the values of these projectors at the initial and final times.
Hence, the evolution semigroup follows the constructed set of projectors in the
adiabatic regime, modulo error terms we control
Entangling power and operator entanglement in qudit systems
We establish the entangling power of a unitary operator on a general
finite-dimensional bipartite quantum system with and without ancillas, and give
relations between the entangling power based on the von Neumann entropy and the
entangling power based on the linear entropy. Significantly, we demonstrate
that the entangling power of a general controlled unitary operator acting on
two equal-dimensional qudits is proportional to the corresponding operator
entanglement if linear entropy is adopted as the quantity representing the
degree of entanglement. We discuss the entangling power and operator
entanglement of three representative quantum gates on qudits: the SUM, double
SUM, and SWAP gates.Comment: 8 pages, 1 figure. Version 3: Figure was improved and the MS was a
bit shortene
Perturbative Formulation and Non-adiabatic Corrections in Adiabatic Quantum Computing Schemes
Adiabatic limit is the presumption of the adiabatic geometric quantum
computation and of the adiabatic quantum algorithm. But in reality, the
variation speed of the Hamiltonian is finite. Here we develop a general
formulation of adiabatic quantum computing, which accurately describes the
evolution of the quantum state in a perturbative way, in which the adiabatic
limit is the zeroth-order approximation. As an application of this formulation,
non-adiabatic correction or error is estimated for several physical
implementations of the adiabatic geometric gates. A quantum computing process
consisting of many adiabatic gate operations is considered, for which the total
non-adiabatic error is found to be about the sum of those of all the gates.
This is a useful constraint on the computational power. The formalism is also
briefly applied to the adiabatic quantum algorithm.Comment: 5 pages, revtex. some references adde
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