12,570 research outputs found

    Hidden unity in the quantum description of matter

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    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

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    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

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    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

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    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

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    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

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    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

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    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 (mG)−1(mG)^{-1} 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

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    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 (mG)−1(mG)^{-1} 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

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    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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