12,622 research outputs found
Hidden unity in the quantum description of matter
We introduce an algebraic framework for interacting quantum systems that
enables studying complex phenomena, characterized by the coexistence and
competition of various broken symmetry states of matter. The approach unveils
the hidden unity behind seemingly unrelated physical phenomena, thus
establishing exact connections between them. This leads to the fundamental
concept of {\it universality} of physical phenomena, a general concept not
restricted to the domain of critical behavior. Key to our framework is the
concept of {\it languages} and the construction of {\it dictionaries} relating
them.Comment: 10 pages 2 psfigures. Appeared in Recent Progress in Many-Body
Theorie
Parental Marital Status and Perceived Parental Marital Stability as Predictors of Avoidant Attachment Style in Young Adult Romantic Relationships
The purpose of the present study was to determine whether parental marital status and perceived marital stability were predictors of avoidant attachment in young adult romantic relationships. It was hypothesized that young adults from intact stable marriages will have the least avoidant attachment style (securely attached), while young adults of intact unstable marriages will have the most avoidant attachment style. It was also hypothesized that the young adult children of divorce will have variable avoidance levels. There were 238 participants in the present study (18-30 years old). Participants completed a Qualtrics survey which included a demographic measure and a revised version of the Adult Attachment Scale (AAS) (Collins & Read, 1990). Two separate 2 X 2 analysis of variance (ANOVAs) were conducted, the first for parental marital status and participant relationship status, the second for perceived parental marital stability and participant relationship status. The first ANOVA demonstrated a significant main effect for marital status, with young adults with married parents reporting significantly lower avoidance scores than those from divorced households. There was also a significant main effect for relationship status, demonstrated by participants in a committed relationship displaying the lowest avoidance scores. The second ANOVA demonstrated a significant main effect for perceived parental marital stability, with participants from an intact stable marriage reporting significantly lower avoidance scores than those from an intact unstable marriage. Implications, limitations, and future research directions are discussed
Modelling Planck-scale Lorentz violation via analogue models
Astrophysical tests of Planck-suppressed Lorentz violations had been
extensively studied in recent years and very stringent constraints have been
obtained within the framework of effective field theory. There are however
still some unresolved theoretical issues, in particular regarding the so called
"naturalness problem" - which arises when postulating that Planck-suppressed
Lorentz violations arise only from operators with mass dimension greater than
four in the Lagrangian. In the work presented here we shall try to address this
problem by looking at a condensed-matter analogue of the Lorentz violations
considered in quantum gravity phenomenology. Specifically, we investigate the
class of two-component BECs subject to laser-induced transitions between the
two components, and we show that this model is an example for Lorentz
invariance violation due to ultraviolet physics. We shall show that such a
model can be considered to be an explicit example high-energy Lorentz
violations where the ``naturalness problem'' does not arise.Comment: Talk given at the Fourth Meeting on Constrained Dynamics and Quantum
Gravity (QG05), Cala Gonone (Sardinia, Italy) September 12-16, 200
A Multi-Band Far-Infrared Survey with a Balloon-Borne Telescope
Nine additional radiation sources, above a 3-sigma confidence level of 1300 Jy, were identified at 100 microns by far infrared photometry of the galactic plane using a 0.4 meter aperture, liquid helium cooled, multichannel far infrared balloon-borne telescope. The instrument is described, including its electronics, pointing and suspension systems, and ground support equipment. Testing procedures and flight staging are discussed along with the reduction and analysis of the data acquired. The history of infrared astronomy is reviewed. General infrared techniques and the concerns of balloon astronomers are explored
General relativity and cosmology derived from principle of maximum power or force
The field equations of general relativity are shown to derive from the
existence of a limit force or of a limit power in nature. The limits have the
value of c^4/4G and c^5/4G. The proof makes use of a result by Jacobson. All
known experimental data is consistent with the limits. Applied to the universe,
the limits predict its darkness at night and the observed scale factor. Some
experimental tests of the limits are proposed. The main counter-arguments and
paradoxes are discussed, such as the transformation under boosts, the force
felt at a black hole horizon, the mountain problem, and the contrast to
scalar--tensor theories of gravitation. The resolution of the paradoxes also
clarifies why the maximum force and the maximum power have remained hidden for
so long. The derivation of the field equations shows that the maximum force or
power plays the same role for general relativity as the maximum speed plays for
special relativity.Comment: 24 pages, 1 figure, LaTeX, published versio
On Unitary Evolution of a Massless Scalar Field In A Schwarzschild Background: Hawking Radiation and the Information Paradox
We develop a Hamiltonian formalism which can be used to discuss the physics
of a massless scalar field in a gravitational background of a Schwarzschild
black hole. Using this formalism we show that the time evolution of the system
is unitary and yet all known results such as the existence of Hawking radiation
can be readily understood. We then point out that the Hamiltonian formalism
leads to interesting observations about black hole entropy and the information
paradox.Comment: 45 pages, revte
Model of black hole evolution
From the postulate that a black hole can be replaced by a boundary on the
apparent horizon with suitable boundary conditions, an unconventional scenario
for the evolution emerges. Only an insignificant fraction of energy of order
is radiated out. The outgoing wave carries a very small part of the
quantum mechanical information of the collapsed body, the bulk of the
information remaining in the final stable black hole geometry.Comment: 9 pages, harvmac, 3 figures, minor addition
Model of black hole evolution
From the postulate that a black hole can be replaced by a boundary on the
apparent horizon with suitable boundary conditions, an unconventional scenario
for the evolution emerges. Only an insignificant fraction of energy of order
is radiated out. The outgoing wave carries a very small part of the
quantum mechanical information of the collapsed body, the bulk of the
information remaining in the final stable black hole geometry.Comment: 9 pages, harvmac, 3 figures, minor addition
General covariance, and supersymmetry without supersymmetry
An unusual four-dimensional generally covariant and supersymmetric SU(2)
gauge theory is described. The theory has propagating degrees of freedom, and
is invariant under a local (left-handed) chiral supersymmetry, which is half
the supersymmetry of supergravity. The Hamiltonian 3+1 decomposition of the
theory reveals the remarkable feature that the local supersymmetry is a
consequence of Yang-Mills symmetry, in a manner reminiscent of how general
coordinate invariance in Chern-Simons theory is a consequence of Yang-Mills
symmetry. It is possible to write down an infinite number of conserved
currents, which strongly suggests that the theory is classically integrable. A
possible scheme for non-perturbative quantization is outlined. This utilizes
ideas that have been developed and applied recently to the problem of
quantizing gravity.Comment: 17 pages, RevTeX, two minor errors correcte
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