Dynamics of particle production by strong electric fields in non-Abelian plasmas (2010)
Dawson, John F., Mihaila, Bogdan, Cooper, Fred
We develop methods for computing the dynamics of fermion pair production by strong color electric fields using the semi-classical Boltzmann-Vlasov equation. We present numerical results for a model...
Backreaction and Particle Production in (3+1)-dimensional QED (2009)
Mihaila, Bogdan, Cooper, Fred, Dawson, John F.
We study the fermion pair production from a strong electric field in boost-invariant coordinates in (3+1) dimensions and exploit the cylindrical symmetry of the problem. This problem has been used...
Coupled-cluster theory of a gas of strongly-interacting fermions in the dilute limit (2009)
Mihaila, Bogdan, Cardenas, Andres
We study the ground-state properties of a dilute gas of strongly-interacting fermions in the framework of the coupled-cluster expansion (CCE). We demonstrate that properties such as universality,...
Cooper, Fred, Dawson, John F., Mihaila, Bogdan
The transverse distribution of gluon and quark-antiquark pairs produced from a strong constant chromo-electric field depends on two gauge invariant quantities, $C_1=E^aE^a$ and...
Mihaila, Bogdan, Dawson, John F., Cooper, Fred
We study two different initial conditions for fermions for the problem of pair production of fermions coupled to a classical electromagnetic field with backreaction in \oneplusone boost-invariant...
Compactons in PT-symmetric generalized Korteweg-de Vries Equations (2008)
Bender, Carl M., Cooper, Fred, Khare, Avinash, Mihaila, Bogdan, Saxena, Avadh
In an earlier paper Cooper, Shepard, and Sodano introduced a generalized KdV equation that can exhibit the kinds of compacton solitary waves that were first seen in equations studied by Rosenau and...
feature article Ab Initio Calculations of Light Nuclei (2008)
Bruce R. Barrett, Bogdan Mihaila, Steven C. Pieper, Robert, B. Wiringa
A major goal in nuclear physics is to understand how nuclear binding, stability, and structure arise from the underlying interactions between individual nucleons. We want to compute the properties of...
Real time particle production in QED and QCD from strong fields and the Back-Reaction problem (2008)
Cooper, Fred, Dawson, John F., Mihaila, Bogdan
We review the history of analytical approaches to particle production from external strong fields in QED and QCD, and numerical studies of the back reaction problem for the electric field in QED. We...
Mihaila, Bogdan, Gaudio, Sergio, Bedell, Kevin S., Blagoev, Krastan B., Timmermans, Eddy
We study the acoustic attenuation rate in the Fermi-Bose model describing a mixtures of bosonic and fermionic atom gases. We demonstrate the dramatic change of the acoustic attenuation rate as the...
Mihaila, Bogdan, Dawson, John F., Cooper, Fred
We obtain a complete set of free-field solutions of the Dirac equation in a (longitudinal) boost-invariant geometry with azimuthal symmetry and use these solutions to perform the canonical...
A quantitative study of spin noise spectroscopy in a classical gas of $^{41}$K atoms (2006)
Mihaila, Bogdan, Crooker, Scott A., Rickel, Dwight G., Blagoev, Krastan B., Littlewood, Peter B., Smith, Darryl L.
We present a general derivation of the electron spin noise power spectrum in alkali gases as measured by optical Faraday rotation, which applies to both classical gases at high temperatures as well...
Spin noise spectroscopy to probe quantum states of ultracold fermionic atomic gases (2006)
Mihaila, Bogdan, Crooker, Scott A., Blagoev, Krastan B., Rickel, Dwight G., Littlewood, Peter B., Smith, Darryl L.
Ultracold alkali atoms provide experimentally accessible model systems for probing quantum states that manifest themselves at the macroscopic scale. Recent experimental realizations of superfluidity...
Phases of a fermionic model with chiral condensates and Cooper pairs in 1+1 dimensions (2006)
Mihaila, Bogdan, Blagoev, Krastan B., Cooper, Fred
We study the phase structure of a 4-fermi model with three bare coupling constants, which potentially has three types of bound states. This model is a generalization of the model discussed previously...
Supersymmetric approximations to the 3D supersymmetric O(N) model (2005)
Dawson, John F., Mihaila, Bogdan, Berglund, Per, Cooper, Fred
We develop several non-perturbative approximations for studying the dynamics of a supersymmetric O(N) model which preserve supersymmetry. We study the phase structure of the vacuum in both the...
Exact solitary wave solutions for a discrete $\lambda \phi^4$ field theory in 1+1 dimensions (2005)
Cooper, Fred, Khare, Avinash, Mihaila, Bogdan, Saxena, Avadh
We have found exact, periodic, time-dependent solitary wave solutions of a discrete $\phi^4$ field theory model. For finite lattices, depending on whether one is considering a repulsive or attractive...
Density and spin response functions in ultracold fermionic atom gases (2005)
Mihaila, Bogdan, Gaudio, Sergio, Blagoev, Krastan B., Balatsky, Alexander V., Littlewood, Peter B., Smith, Darryl L.
We propose a new method of detecting the onset of superfluidity in a two-component ultracold fermionic gas of atoms governed by an attractive short-range interaction. By studying the two-body...
Cooper, Fred, Dawson, John F., Mihaila, Bogdan
We derive the renormalized Schwinger-Dyson equations for the one- and two-point functions in the auxiliary field formulation of $\lambda \phi^4$ field theory to order 1/N in the 2PI-1/N expansion. We...
BCS-BEC crossover with a finite-range interaction (2004)
Parish, Meera M., Mihaila, Bogdan, Timmermans, Eddy M., Blagoev, Krastan B., Littlewood, Peter B.
We study the crossover from BEC to BCS pairing for dilute systems but with a realistic finite-range interaction. We exhibit the changes in the excitation spectrum that provide a clean qualitative...
Cooper, Fred, Mihaila, Bogdan, Dawson, John F.
In this paper we study the renormalization of the Schwinger-Dyson equations that arise in the auxiliary field formulation of the O(N) $\phi^4$ field theory. The auxiliary field formulation allows a...
Continuum coupled cluster expansion (2003)
We review the basics of the coupled-cluster expansion formalism for numerical solutions of the many-body problem, and we outline the principles of an approach directed towards an adequate inclusion...
Real-time dynamics of the O(N) model in 1+1 dimensions (2003)
We study the non-equilibrium dynamics of the O(N) model in classical and quantum field theory in 1+1 dimensions, for N > 1. We compare numerical results obtained using the Hartree approximation and...
Quantum dynamics of phase transitions in broken symmetry $\lambda \phi^4$ field theory (2002)
Cooper, Fred, Dawson, John F., Mihaila, Bogdan
We perform a detailed numerical investigation of the dynamics of broken symmetry $\lambda \phi^4$ field theory in 1+1 dimensions using a Schwinger-Dyson equation truncation scheme based on ignoring...
Dynamics of broken symmetry lambda phi^4 field theory (2002)
Cooper, Fred, Dawson, John F., Mihaila, Bogdan
We study the domain of validity of a Schwinger-Dyson (SD) approach to non-equilibrium dynamics when there is broken symmetry. We perform exact numerical simulations of the one- and two-point...
Mihaila, Bogdan, Gurvitz, Shmuel A., Dean, David, Nazarewicz, Witold
To model the decay of a quasibound state we use the modified two-potential approach introduced by Gurvitz and Kalbermann. This method has proved itself useful in the past for calculating the decay...
Parallel algorithm with spectral convergence for nonlinear integro-differential equations (2002)
Mihaila, Bogdan, Shaw, Ruth E.
We discuss a numerical algorithm for solving nonlinear integro-differential equations, and illustrate our findings for the particular case of Volterra type equations. The algorithm combines a...
Continuum versus periodic lattice Monte Carlo approach to classical field theory (2001)
Mihaila, Bogdan, Dawson, John F.
We compare the momentum space with the standard periodic lattice approach to Monte Carlo calculations in classical $\phi^4$ field theory. We show that the mismatch in the initial value of...
Schwinger-Dyson approach to non-equilibrium classical field theory (2001)
Blagoev, Krastan, Cooper, Fred, Dawson, John, Mihaila, Bogdan
In this paper we discuss a Schwinger-Dyson [SD] approach for determining the time evolution of the unequal time correlation functions of a non-equilibrium classical field theory, where the classical...
Resumming the large-N approximation for time evolving quantum systems (2000)
Mihaila, Bogdan, Cooper, Fred, Dawson, John F.
In this paper we discuss two methods of resumming the leading and next to leading order in 1/N diagrams for the quartic O(N) model. These two approaches have the property that they preserve both...
Exact and approximate dynamics of the quantum mechanical O(N) model (2000)
Mihaila, Bogdan, Athan, Tara, Cooper, Fred, Dawson, John, Habib, Salman
We study a quantum dynamical system of N, O(N) symmetric, nonlinear oscillators as a toy model to investigate the systematics of a 1/N expansion. The closed time path (CTP) formalism melded with an...
Ground state correlations and mean-field in $^{16}$O: Part II (1999)
Mihaila, Bogdan, Heisenberg, Jochen H.
We continue the investigations of the $^{16}$O ground state using the coupled-cluster expansion [$\exp({\bf S})$] method with realistic nuclear interaction. In this stage of the project, we take into...
Three-body matrix elements for calculations of mean field and exp(S) ground sate correlations (1999)
Mihaila, Bogdan, Heisenberg, Jochen H.
In this document we present our approach to the computation of three-body matrix elements, based on the Urbana family of three-nucleon potentials. The calculations refer only to the necessary matrix...
Microscopic calculation of the inclusive electron scattering structure function in O-16 (1999)
Mihaila, Bogdan, Heisenberg, Jochen
We calculate the charge form factor and the longitudinal structure function for $^{16}$O and compare with the available experimental data, up to a momentum transfer of 4 fm$^{-1}$. The ground state...
Numerical Approximations Using Chebyshev Polynomial Expansions (1999)
Mihaila, Bogdan, Mihaila, Ioana
We present numerical solutions for differential equations by expanding the unknown function in terms of Chebyshev polynomials and solving a system of linear equations directly for the values of the...
The quantum roll in d-dimensions and the large-d expansion (1998)
Mihaila, Bogdan, Dawson, John F., Cooper, Fred, Brewster, Mary, Habib, Salman
We investigate the quantum roll for a particle in a $d$-dimensional ``Mexican hat'' potential in quantum mechanics, comparing numerical simulations in $d$-dimensions with the results of a large-$d$...
Ground state correlations and mean-field in $^{16}$O (1998)
Heisenberg, Jochen H., Mihaila, Bogdan.
We use the coupled cluster expansion ($\exp(S)$ method) to generate the complete ground state correlations due to the NN interaction. Part of this procedure is the calculation of the two-body G...
Ground state correlations and mean field using the exp(S) method (1998)
Heisenberg, Jochen H., Mihaila, Bogdan
This document gives a detailed account of the terms used in the computation of the ground state mean field and the ground state correlations. While the general approach to this description is given...
Center-of-mass corrections revisited: a many-body expansion approach (1998)
Mihaila, Bogdan, Heisenberg, Jochen H.
A many-body expansion for the computation of the charge form factor in the center-of-mass system is proposed. For convergence testing purposes, we apply our formalism to the case of the harmonic...
Computation of Two-Body Matrix Elements From the Argonne $v_{18}$ Potential (1998)
Mihaila, Bogdan, Heisenberg, Jochen H.
We discuss the computation of two-body matrix elements from the Argonne $v_{18}$ interaction. The matrix elements calculation is presented both in particle-particle and in particle-hole angular...
Ground state of [16]O /--by Bogdan Mihaila. (1998)
Number 16 in title appears in superscript.
Mihaila, Bogdan, Dawson, John F., Cooper, Fred
We solve numerically to order 1/N the time evolution of a quantum dynamical system of N oscillators of mass m coupled quadratically to a massless dynamic variable. We use Schwinger's closed time path...