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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Long-Lived Time-Dependent Remnants During Cosmological Symmetry Breaking: From Inflation To The Electroweak Scale, Marcelo Gleiser, Noah Graham, Nikitas Stamatopoulos
Long-Lived Time-Dependent Remnants During Cosmological Symmetry Breaking: From Inflation To The Electroweak Scale, Marcelo Gleiser, Noah Graham, Nikitas Stamatopoulos
Dartmouth Scholarship
Through a detailed numerical investigation in three spatial dimensions, we demonstrate that long-lived time-dependent field configurations emerge dynamically during symmetry breaking in an expanding de Sitter spacetime. We investigate two situations: a single scalar field with a double-well potential and an SU(2) non-Abelian Higgs model. For the single scalar, we show that large-amplitude oscillon configurations emerge spontaneously and persist to contribute about 1.2% of the energy density of the Universe. We also show that for a range of parameters, oscillon lifetimes are enhanced by the expansion and that this effect is a result of parametric resonance. For the SU(2) case, …
Class Of Nonperturbative Configurations In Abelian-Higgs Models: Complexity From Dynamical Symmetry Breaking, M. Gleiser, J. Thorarinson
Class Of Nonperturbative Configurations In Abelian-Higgs Models: Complexity From Dynamical Symmetry Breaking, M. Gleiser, J. Thorarinson
Dartmouth Scholarship
We present a numerical investigation of the dynamics of symmetry breaking in both Abelian and non-Abelian [SU(2)] Higgs models in three spatial dimensions. We find a class of time-dependent, long-lived nonperturbative field configurations within the range of parameters corresponding to type-1 superconductors, that is, with vector masses (mv) larger than scalar masses (ms). We argue that these emergent nontopological configurations are related to oscillons found previously in other contexts. For the Abelian-Higgs model, our lattice implementation allows us to map the range of parameter space—the values of β=(ms/mv)2—where such configurations exist and to follow them for times t∼O(105)m−1. An investigation …
Bubbling The False Vacuum Away, M. Gleiser, B. Rogers, J. Thorarinson
Bubbling The False Vacuum Away, M. Gleiser, B. Rogers, J. Thorarinson
Dartmouth Scholarship
We investigate the role of nonperturbative, bubble-like inhomogeneities on the decay rate of false- vacuum states in two and three-dimensional scalar field theories. The inhomogeneities are induced by setting up large-amplitude oscillations of the field about the false vacuum as, for example, after a rapid quench or in certain models of cosmological inflation. We show that, for a wide range of parameters, the presence of large-amplitude bubble-like inhomogeneities greatly accelerates the de- cay rate, changing it from the well-known exponential suppression of homogeneous nucleation to a power-law suppression. It is argued that this fast, power-law vacuum decay – known as …
Energy Landscape Of D -Dimensional Q -Balls, Marcelo Gleiser, Joel Thorarinson
Energy Landscape Of D -Dimensional Q -Balls, Marcelo Gleiser, Joel Thorarinson
Dartmouth Scholarship
We investigate the properties of Q-balls in d spatial dimensions. First, a generalized virial relation for these objects is obtained. We then focus on potentials V(ϕϕ†)=∑3n=1an(ϕϕ†)n, where an is a constant and n is an integer, obtaining variational estimates for their energies for arbitrary charge Q. These analytical estimates are contrasted with numerical results and their accuracy evaluated. Based on the results, we offer a simple criterion to classify large and small d-dimensional Q-balls for this class of potentials. A minimum charge is then computed and its dependence on spatial dimensionality is shown to scale as Qmin∼exp(d). We also briefly …
Cosmic Shear Of The Microwave Background: The Curl Diagnostic, Asantha Cooray, Marc Kamionkowski, Robert R. Caldwell
Cosmic Shear Of The Microwave Background: The Curl Diagnostic, Asantha Cooray, Marc Kamionkowski, Robert R. Caldwell
Dartmouth Scholarship
Weak-lensing distortions of the cosmic-microwave-background (CMB) temperature and polarization patterns can reveal important clues to the intervening large-scale structure. The effect of lensing is to deflect the primary temperature and polarization signal to slightly different locations on the sky. Deflections due to density fluctuations, gradient-type for the gradient of the projected gravitational potential, give a direct measure of the mass distribution. Curl-type deflections can be induced by, for example, a primordial background of gravitational waves from inflation or by second-order effects related to lensing by density perturbations. Whereas gradient-type deflections are expected to dominate, we show that curl-type deflections can …
Mass Spectrum And Correlation Functions Of Non-Abelian Quantum Magnetic Monopoles, E. C. Marino, Rudnei O. Ramos
Mass Spectrum And Correlation Functions Of Non-Abelian Quantum Magnetic Monopoles, E. C. Marino, Rudnei O. Ramos
Dartmouth Scholarship
The method of quantization of magnetic monopoles based on the order-disorder duality existing between the monopole operator and the Lagrangian fields is applied to the description of the quantum magnetic monopoles of't Hooft and Polyakov in the SO(3) Georgi-Glashow model. The commutator of the monopole operator with the magnetic charge is computed explicitly, indicating that indeed the quantum monopole carries 4πg units of magnetic charge. An explicit expression for the asymptotic behavior of the monopole correlation function is derived. From this, the mass of the quantum monopole is obtained. The tree-level result for the quantum monopole mass is shown to …
Microphysical Approach To Nonequilibrium Dynamics Of Quantum Fields, Marcelo Gleiser, Rudnei O. Ramos
Microphysical Approach To Nonequilibrium Dynamics Of Quantum Fields, Marcelo Gleiser, Rudnei O. Ramos
Dartmouth Scholarship
We examine the nonequilibrium dynamics of a self-interacting λφ4 scalar field theory. Using a real time formulation of finite temperature field theory we derive, up to two loops and O(λ2), the effective equation of motion describing the approach to equilibrium. We present a detailed analysis of the approxi- mations used in order to obtain a Langevin-like equation of motion, in which the noise and dissipation terms associated with quantum fluctuations obey a fluctuation-dissipation relation. We show that, in general, the noise is colored (time-dependent) and multiplicative (couples nonlinearly to the field), even though it is still Gaussian distributed. The noise …
Pseudostable Bubbles, Marcelo Gleiser
Pseudostable Bubbles, Marcelo Gleiser
Dartmouth Scholarship
The evolution of spherically symmetric unstable scalar field configura- tions (“bubbles”) is examined for both symmetric (SDWP) and asymmet- ric (ADWP) double-well potentials. Bubbles with initial static energiesE0 ∼< Ecrit, where Ecrit is some critical value, shrink in a time scale deter- mined by their linear dimension, or “radius”. Bubbles with E0 ∼> Ecrit evolve into time-dependent, localized configurations which are very long-lived com- pared to characteristic time-scales in the models examined. The stability of these configurations is investigated and possible applications are briefly discussed.