Nonthermal fixed points and the functional renormalization group (2008)
Nonthermal fixed points represent basic properties of quantum field theories, in addition to vacuum or thermal equilibrium fixed points. The functional renormalization group on a closed real-time...
Berges, J., Rothkopf, A., Schmidt, J.
Strongly correlated systems far from equilibrium can exhibit scaling solutions with a dynamically generated weak coupling. We show this by investigating isolated systems described by relativistic...
J. Berges, DESY Forschung Hochenergiephysik, A. Rothkopf, J. Schmidt
Internal report | Preprint
Bottom-up isotropization in classical-statistical lattice gauge theory (2007)
Berges, J., Scheffler, S., Sexty, D.
We compute nonequilibrium dynamics for classical-statistical SU(2) pure gauge theory on a lattice. We consider anisotropic initial conditions with high occupation numbers in the transverse plane on a...
Real-time gauge theory simulations from stochastic quantization with optimized updating (2007)
We investigate simulations for gauge theories on a Minkowskian space-time lattice. We employ stochastic quantization with optimized updating using stochastic reweighting or gauge fixing,...
Quantum versus classical statistical dynamics of an ultracold Bose gas (2007)
We investigate the conditions under which quantum fluctuations are relevant for the quantitative interpretation of experiments with ultracold Bose gases. This requires to go beyond the description in...
Progress in nonequilibrium quantum field theory III (2006)
We review recent developments and open questions for the description of nonequilibrium quantum fields, continuing hep-ph/0302210 and hep-ph/0410330.
Lattice simulations of real-time quantum fields (2006)
Berges, J., Borsanyi, Sz., Sexty, D.
We investigate lattice simulations of scalar and nonabelian gauge fields in Minkowski space-time. For SU(2) gauge-theory expectation values of link variables in 3+1 dimensions are constructed by a...
Ultracold atomic quantum gases far from equilibrium (2006)
Gasenzer, T., Berges, J., Schmidt, M. G., Seco, M.
We calculate the time evolution of a far-from-equilibrium initial state of a non-relativistic ultracold Bose gas in one spatial dimension. The non-perturbative approximation scheme is based on a...
Nonperturbative renormalization for 2PI effective action techniques (2006)
Berges, J., Borsany, S., Reinosa, U., Serreau, J.
Nonperturbative approximation schemes based on two-particle irreducible (2PI) effective actions provide an important means for our current understanding of (non-)equilibrium quantum field theory. A...
Nonequilibrium quantum fields from first principles (2005)
Calculations of nonequilibrium processes become increasingly feasable in quantum field theory from first principles. There has been important progress in our analytical understanding based on 2PI...
Simulating nonequilibrium quantum fields with stochastic quantization techniques (2005)
We present lattice simulations of nonequilibrium quantum fields in Minkowskian space-time. Starting from a non-thermal initial state, the real-time quantum ensemble in 3+1 dimensions is constructed...
Isotropization far from equilibrium (2005)
Berges, J., Borsanyi, Sz., Wetterich, C.
Isotropization occurs on time scales much shorter than the thermal equilibration time. This is a crucial ingredient for the understanding of collision experiments of heavy nuclei or other...
Nonperturbative renormalization for 2PI effective action techniques (2005)
Berges, J., Borsany, S., Reinosa, U., Serreau, J.
Nonperturbative approximation schemes based on two-particle irreducible (2PI) effective actions provide an important means for our current understanding of (non-)equilibrium quantum field theory. A...
Nonperturbative renormalization for 2PI effective action techniques (2005)
Berges, J., Borsany, S., Reinosa, U., Serreau, J.
Nonperturbative approximation schemes based on two-particle irreducible (2PI) effective actions provide an important means for our current understanding of (non-)equilibrium quantum field theory. A...
Progress in nonequilibrium quantum field theory II (2004)
We review recent developments for the description of nonequilibrium quantum fields, continuing hep-ph/0302210.
Introduction to Nonequilibrium Quantum Field Theory (2004)
There has been substantial progress in recent years in the quantitative understanding of the nonequilibrium time evolution of quantum fields. Important topical applications, in particular in high...
Renormalized thermodynamics from the 2PI effective action (2004)
Berges, J., Borsanyi, Sz., Reinosa, U., Serreau, J.
High-temperature resummed perturbation theory is plagued by poor convergence properties. The problem appears for theories with bosonic field content such as QCD, QED or scalar theories. We calculate...
The genome of the diatom Thalassiosira pseudonana: Ecology, evolution, and metabolism (2004)
Ambrust, E.V., Berges, J., Bowler, C., Green, B., Martinez, D., Putnam, N., ...
Critical phenomena from the two-particle irreducible 1/N expansion (2004)
Alford, M., Berges, J., Cheyne, J. M.
The 1/N expansion of the two-particle irreducible (2PI) effective action is employed to compute universal properties at the second-order phase transition of an O(N)-symmetric N-vector model directly...
Berges, J., Borsanyi, S., Wetterich, C.
Prethermalization of the equation of state and the kinetic temperature to their equilibrium values occurs on time scales dramatically shorter than the thermal equilibration time. This is a crucial...
n-Particle irreducible effective action techniques for gauge theories (2004)
A loop or coupling expansion of a so-called n-particle irreducible (nPI) generating functional provides a well-defined approximation scheme in terms of self-consistently dressed propagators and...
Critical Phenomena in Continuous Dimension (2003)
Ballhausen, H., Berges, J., Wetterich, C.
We present a calculation of critical phenomena directly in continuous dimension d employing an exact renormalization group equation for the effective average action. For an Ising-type scalar field...
Progress in Nonequilibrium Quantum Field Theory (2003)
We review recent developments for the description of far-from-equilibrium dynamics of quantum fields and subsequent thermalization.
Thermalization of fermionic quantum fields (2002)
Berges, J., Borsanyi, Sz., Serreau, J.
We solve the nonequilibrium dynamics of a 3+1 dimensional theory with Dirac fermions coupled to scalars via a chirally invariant Yukawa interaction. The results are obtained from a systematic...
Nonequilibrium quantum fields with large fluctuations (2002)
We consider the nonequilibrium evolution of an O(N)-symmetric scalar quantum field theory using a systematic two-particle irreducible 1/N-expansion to next-to-leading order, which includes scattering...
Parametric resonance in quantum field theory (2002)
We present the first study of parametric resonance in quantum field theory from a complete next-to-leading order calculation in a 1/N-expansion of the 2PI effective action, which includes scattering...
Far-from-equilibrium dynamics with broken symmetries from the 2PI-1/N expansion (2002)
Aarts, G., Ahrensmeier, D., Baier, R., Berges, J., Serreau, J.
We derive the nonequilibrium real-time evolution of an O(N) - invariant scalar quantum field theory in the presence of a nonvanishing expectation value of the quantum field. Using a systematic 1/N...
Nonequilibrium Quantum Fields and the Classical Field Theory Limit (2002)
We calculate the far-from-equilibrium dynamics and thermalization both for the quantum and the classical O(N)--model. The early and late-time behavior can be described from the 2PI--loop expansion...
Quantum Fields far from Equilibrium and Thermalization (2001)
I review the use of the 2PI effective action in nonequilibrium quantum field theory. The approach enables one to find approximation schemes which circumvent long-standing problems of non-thermal or...
Controlled nonperturbative dynamics of quantum fields out of equilibrium (2001)
We compute the nonequilibrium real-time evolution of an O(N)-symmetric scalar quantum field theory from a systematic 1/N expansion of the 2PI effective action to next-to-leading order, which includes...
Nonequilibrium time evolution of the spectral function in quantum field theory (2001)
Transport or kinetic equations are often derived assuming a quasi-particle (on-shell) representation of the spectral function. We investigate this assumption using a three-loop approximation of the...
Higgs description of two-flavor QCD vacuum (2000)
A Higgs description for the QCD vacuum in the limit of two quark flavors is proposed. Complete ``spontaneous breaking'' of color symmetry is realized by condensation of an adjoint quark-antiquark and...
Quark description of nuclear matter (2000)
We discuss the role of an adjoint chiral condensate for color superconducting quark matter. Its presence leads to color-flavor locking in two-flavor quark matter. Color is broken completely as well...
Thermalization of Quantum Fields from Time-Reversal Invariant Evolution Equations (2000)
We study the time evolution of correlation functions in closed quantum systems for nonequilibrium ensembles of initial conditions. For a scalar quantum field theory we show that generic time-reversal...
Non-Perturbative Renormalization Flow in Quantum Field Theory and Statistical Physics (2000)
Berges, J., Tetradis, N., Wetterich, C.
We review the use of an exact renormalization group equation in quantum field theory and statistical physics. It describes the dependence of the free energy on an infrared cutoff for the quantum or...
Magnetic fields within color superconducting neutron star cores (1999)
Alford, M., Berges, J., Rajagopal, K.
We discuss the Meissner effect for a color superconductor formed by cold dense quark matter. Though color and ordinary electromagnetism are broken in a color superconductor, there is a linear...
Gapless Color Superconductivity (1999)
Alford, M., Berges, J., Rajagopal, K.
We present the dispersion relations for quasiparticle excitations about the color-flavor locked ground state of QCD at high baryon density. In the presence of condensates which pair light and strange...
Unlocking Color and Flavor in Superconducting Strange Quark Matter (1999)
Alford, M., Berges, J., Rajagopal, K.
We explore the phase diagram of strongly interacting matter with massless u and d quarks as a function of the strange quark mass m_s and the chemical potential mu for baryon number. Neglecting...
QCD in Extreme Conditions and the Wilsonian `Exact Renormalization Group' (1999)
This is an introduction to the use of nonperturbative flow equations in strong interaction physics at nonzero temperature and baryon density. We investigate the QCD phase diagram as a function of...
Quark and Nuclear Matter in the Linear Chiral Meson Model (1998)
We present an analytical description of the phase transitions from a nucleon gas to nuclear matter and from nuclear matter to quark matter within the same model. The equation of state for quark and...
The Chiral Phase Transition at High Baryon Density from Nonperturbative Flow Equations (1998)
We investigate the QCD chiral phase transition at high baryon number density within the linear quark meson model for two flavors. The method we employ is based on an exact renormalization group...
QCD at high Baryon Density and Temperature: Competing Condensates and the Tricritical Point (1998)
The phase diagram of strongly interacting matter is explored as a function of temperature and baryon number density. We investigate the possible simultaneous formation of condensates in the...
Critical Equation of State From the Average Action (1998)
The scaling form of the critical equation of state is computed for O(N)-symmetric models. We employ a method based on an exact flow equation for a coarse grained free energy. A suitable truncation is...
We explore the phase diagram of strongly interacting matter as a function of temperature and baryon number density, using a class of models for two-flavor QCD in which the interaction between quarks...
Universal Critical Equation of State and the Chiral Phase Transition in QCD (1997)
We employ non-perturbative flow equations to compute the equation of state for two flavor QCD within an effective quark meson model. This yields the temperature and quark mass dependence of...
Chiral Phase Transition from Non-Perturbative Flow Equations (1997)
We employ non-perturbative flow equations to compute the equation of state for two flavor QCD within an effective quark meson model. Our treatment covers both the chiral perturbation theory domain of...
Two flavor chiral phase transition from nonperturbative flow equations (1997)
We employ nonperturbative flow equations to compute the equation of state for two flavor QCD within an effective quark meson model. This yields the temperature and quark mass dependence of quantities...
Coarse graining and first-order phase transitions (1996)
Berges, J, Tetradis, N, Wetterich, C
We discuss the dependence of the coarse grained free energy and the classical interface tension on the coarse graining scale $k$. A stable range appears only if the renormalized dimensionless...
Coarse graining and first order phase transitions (1996)
Berges, J., Tetradis, N., Wetterich, C.
We discuss the dependence of the coarse grained free energy and the classical interface tension on the coarse graining scale $k$. A stable range appears only if the renormalized dimensionless...
Field theory near the critical temperature (1996)
Field theory at nonvanishing temperature beyond perturbation theory is discussed for the $N$-component $O(N)$-symmetric scalar theory. We compute the effective potential directly in three dimensions...
Equation of state and coarse grained free energy for matrix models (1996)
We investigate phase transitions in three dimensional scalar matrix models, with special emphasis on complex $2 \times 2$ matrices. The universal equation of state for weak first order phase...
Critical equation of state from the average action (1995)
Berges, J., Tetradis, N., Wetterich, C.
The scaling form of the critical equation of state is computed for $O(N)$-symmetric models. We employ a method based on an exact flow equation for a coarse grained free energy. A suitable truncation...
Solving non-perturbative flow equations (1995)
Adams, J., Berges, J., Bornholdt, S., Freire, F., Tetradis, N., Wetterich, C.
Non-perturbative exact flow equations describe the scale dependence of the effective average action. We present a numerical solution for an approximate form of the flow equation for the potential in...
Identification of centrosomal proteins in a human lymphoblastic cell line.
Gosti-Testu, F, Marty, M C, Berges, J, Maunoury, R, Bornens, M
Highly enriched preparations of centrosomes from human T-lymphoblasts KE 37 were analyzed for their protein content. The specific pattern of polypeptides was characterized by an abundant subset of...
Identification of centrosomal proteins in a human lymphoblastic cell line.
Gosti-Testu, F, Marty, M C, Berges, J, Maunoury, R, Bornens, M
Highly enriched preparations of centrosomes from human T-lymphoblasts KE 37 were analyzed for their protein content. The specific pattern of polypeptides was characterized by an abundant subset of...