Quark-gluon plasma phase transition using cluster expansion method
Syam Kumar, A. M.; Prasanth, J. P.; Bannur, Vishnu M.
2015-08-01
This study investigates the phase transitions in QCD using Mayer's cluster expansion method. The inter quark potential is modified Cornell potential. The equation of state (EoS) is evaluated for a homogeneous system. The behaviour is studied by varying the temperature as well as the number of Charm Quarks. The results clearly show signs of phase transition from Hadrons to Quark-Gluon Plasma (QGP).
Deconfining Phase Transition to a Quark-Gluon Plasma in Different SU(3) Color Representations
Mezouar, K.; Ait El Djoudi, A.; Ghenam, L.
2016-10-01
For a statistical description of the quark gluon plasma (QGP) considering its internal symmetry, we calculate its partition function using the group theoretical projection method. We project out the partition function of a QGP consisting of gluons, massless up and down quarks, and massive strange quarks onto the singlet representation of the SU(3) color group, as well as onto the color octet and the color 27-plet representations. A comparison of these color representations is done, by studying their effects on the behavior of some thermodynamical quantities characterizing the mixed hadronic gas-QGP system undergoing a thermal deconfining phase transition on one side, and on the free energy during the formation of a QGP droplet from the hot hadronic gas on another side.
Equation of state for hot quark-gluon plasma transitions to hadrons with full QCD potential
Sheikholeslami-Sabzevari, Bijan
2002-05-01
A practical method based on Mayer's cluster expansion to calculate critical values for a quark-gluon plasma (QGP) phase transition to hadrons is represented. It can be applied to a high-temperature QGP for clustering of quarks to mesons and baryons. The potential used is the Cornell potential, i.e., a potential containing both confining and gluon exchange terms. Debye screening effects are included. An equation of state (EOS) for hadron production is found by analytical methods, which is valid near the critical point. The example of the formation of J/ψ and Υ is recalculated. It is shown that in the range of temperatures available by today's accelerators, the latter particles are suppressed. This is further confirmation for heavy quarkonia suppression and, hence, for a signature of a QGP. The EOS presented here also shows that in future colliders there will be no heavy quarkonia production by the mechanism of phase transition. Hence, if there will be heavy quarkonia production, it must be based on some other mechanisms, perhaps on the basis of some recently suggested possibilities.
Magnetic Phase Diagram of Dense Holographic Multiquarks in the Quark-gluon Plasma
Burikham, Piyabut
2011-01-01
We study phase diagram of the dense holographic gauge matter in the Sakai-Sugimoto model in the presence of the magnetic field above the deconfinement temperature. Even above the deconfinement, quarks could form colour bound states through the remaining strong interaction if the density is large. We demonstrate that in the presence of the magnetic field for a sufficiently large baryon density, the multiquark-pion gradient (MQ-$\\mathcal{5}\\phi$) phase is more thermodynamically preferred than the chiral-symmetric quark-gluon plasma. The phase diagrams between the holographic multiquark and the chiral-symmetric quark-gluon plasma phase are obtained at finite temperature and magnetic field. In the mixed MQ-$\\mathcal{5}\\phi$ phase, the pion gradient induced by the external magnetic field is found to be a linear response for small and moderate field strengths. Its population ratio decreases as the density is raised and thus the multiquarks dominate the phase. Temperature dependence of the baryon chemical potential,...
Primordial Magnetic Field Via Weibel Instability In The Quark Gluon Plasma Phase
Atreya, Abhishek
2016-01-01
The origin of the observed large scale magnetic fields in the Universe is a mystery. The seed of these magnetic fields has been attributed to physical process in the early universe. In this work we provide a mechanism for the generation of a primordial magnetic field in the early universe via the Weibel instability in the quark gluon plasma. The Weibel instability occurs in the plasma if there is an anisotropy in the particle distribution function of the particles. In early universe, the velocity anisotropy required for Weibel instability to operate is generated in the quark gluon plasma by the collapse of closed $Z(3)$ domain walls that arise in the deconfined phase of the QCD (above $T\\sim 200$ MeV). Such large domains can arise in the context of certain low energy scale inflationary models. The closed domains undergo supersonic collapse and the velocity anisotropy is generated in the shocks produced in the wake of the collapsing domain walls. This results in a two stream Weibel instability in the ultra-rel...
2016-01-01
This is the fifth volume in the series on the subject of quark-gluon plasma, a unique phase created in heavy-ion collisions at high energy. It contains review articles by the world experts on various aspects of quark-gluon plasma taking into account the advances driven by the latest experimental data collected at both the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC). The articles are pedagogical and comprehensive which can be helpful for both new researchers entering the field as well as the experienced physicists working on the subject.
Nonperturbative effects in a rapidly expanding quark gluon plasma
Mohanty, A K; Gleiser, Marcello; 10.1103/PhysRevC.65.034908
2002-01-01
Within first-order phase transitions, we investigate pretransitional effects due to the nonperturbative, large-amplitude thermal fluctuations which can promote phase mixing before the critical temperature is reached from above. In contrast with the cosmological quark-hadron transition, we find that the rapid cooling typical of the relativistic heavy ion collider and large hadron collider experiments and the fact that the quark-gluon plasma is chemically unsaturated suppress the role of nonperturbative effects at current collider energies. Significant supercooling is possible in a (nearly) homogeneous state of quark gluon plasma. (24 refs).
Indian Academy of Sciences (India)
C P Singh
2000-04-01
Recent trends in the research of quark gluon plasma (QGP) are surveyed and the current experimental and theoretical status regarding the properties and signals of QGP is reported. We hope that the experiments commencing at relativistic heavy-ion collider (RHIC) in 2000 will provide a glimpse of the QGP formation.
Nayak, Tapan; Sarkar, Sourav
2014-01-01
At extremely high temperatures and densities, protons and neutrons may dissolve into a "soup" of quarks and gluons, called the Quark-Gluon Plasma (QGP). For a few microseconds, shortly after the Big Bang, the Universe was filled with the QGP matter. The search and study of Quark-Gluon Plasma (QGP) is one of the most fundamental research topics of our times. The QGP matter has been probed by colliding heavy ions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, New York and the Large Hadron Collider at CERN, Geneva. By colliding heavy-ions at a speed close to that of light, scientists aim to obtain - albeit over a tiny volume of the size of a nucleus and for an infinitesimally short instant - a QGP state. This QGP state can be observed by dedicated experiments, as it reverts to hadronic matter through expansion and cooling. This volume presents some of the current theoretical and experimental understandings in the field of QGP.
Berdnikov, Yu A; Ivanov, A N; Ivanova, V A; Kosmach, V F; Samsonov, V M; Troitskaya, N I; Berdnikov, Ya. A.
2000-01-01
We describe the quark gluon plasma (QGP) as a thermalized quark-gluon system, the thermalized QGP phase of QCD. The hadronization of the thermalized QGP phase is given in a way resembling a simple coalescence model. The input parameters of the approach are the spatial volumes of the hadronization. We introduce three dimensionless parameters C_M, C_B and C_\\bar{B} related to the spatial volumes of the production of low-lying mesons (M), baryons (B) and antibaryons (\\bar{B}). We show that at the temperature T= 175 MeV our predictions for the ratios of multiplicities agree good with the presently available set of hadron ratios measured for various experiments given by NA44, NA49, NA50 and WA97 Collaborations on Pb+Pb collisions at 158 GeV/nucleon, NA35 Collaboration on S+S collisions and NA38 Collaboration on O+U and S+U collisions at 200 GeV/nucleon.
Supercooling of rapidly expanding quark-gluon plasma
Zabrodin, E E; Csernai, László P; Stöcker, H; Greiner, W
1998-01-01
We reexamine the scenario of homogeneous nucleation of the quark-gluon plasma produced in ultra-relativistic heavy ion collisions. A generalization of the standard nucleation theory to rapidly expanding system is proposed. The nucleation rate is derived via the new scaling parameter $\\lambda_Z$. It is shown that the size distribution of hadronic clusters plays an important role in the dynamics of the phase transition. The longitudinally expanding system is supercooled to about 3-6%, then it is reheated, and the hadronization is completed within 6-10 fm/c, i.e. 5-10 times faster than it was estimated earlier, in a strongly nonequilibrium way.
Quark-Gluon Plasma: from accelerator experiments to early Universe
Rosnet, P
2015-01-01
In the Big Bang scenario, the early Universe is characterized by the {\\it particle era}, i.e. a Universe made of particles. This period connects both scales of fundamental physics: infinitesimally small and infinitely large. So, particle physics and in particular experimental programs at accelerators can bring valuable inputs for the understanding of the early Universe and its evolution. These proceedings discuss the impact of the Quantum ChromoDynamics phase transition experienced by the {\\it particle era} in the expanding Universe, which is connected to the study of the Quark-Gluon Plasma produced in heavy-ion physics experiments.
Inflating metastable quark-gluon plasma universe.
Jenkovszky, L.
The cosmic evolution of our universe before and after the assumed confinement phase transition is studied within the homogeneous, isotropic and spatially flat model. The Friedmann equation, describing its evolution is appended by an equation of state (EOS) of the quark-gluon plasma. A specifically interesting feature of this EOS, derived both in the content of the quark model (and quantum chromodynamics) and the S-matrix formulation of statistical mechanics is the presence of a local minimum in the pressure vs. temperature dependence, that may be the origin of the exponential expansion of our universe, called inflation. The conditions necessary for the deep supercooling, accompanied by nucleation in a first-order phase transition, have been investigated. The nucleation rate (and consequently the probability of the deep supercooling indispensable for the inflation) are shown to depend essentially on the surface tension of the created bubbles. The possibility of a "nuclear inflation" - the analogue of the above scenario in heavy ion collisions - is also discussed.
Intermediate mass dilepton production during the chemical equilibration of quark gluon plasma
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The production of dileptons from the chemically equilibrating quark gluon plasma in the intermediate mass region has been studied. Comparing with the calculated results based on the thermodynamic equilibrium system of quark gluon plasma, it has been found that the quark phase of the chemically equilibrating system gives rise to an even larger enhancement of the dileptons production. Therefore, such an enhancement of dilepton production may signal the formation of quark gluon plasma.
Collective Flow signals the Quark Gluon Plasma
Bratkovskaya, E. L.; Bleicher, M.; Greiner, C.; Muronga, A.; Paech, K.; Reiter, M.; Scherer, S.; Soff, S.; Xu, Z.; Zeeb, G.; Zschiesche, D.; Tavares, B.; Portugal, L.; Aguiar, C.; Kodama, T.; Grassi, F.; Hama, Y.; Osada, T.; Sokolowski, O.; Werner, K.; Gallmeister, K.; Cassing, W.; Stöcker, H.
2004-12-01
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 AṡGeV: here the hydrodynamic model has predicted the collapse of the v1-flow and of the v2-flow at ˜ 10 AṡGeV; at 40 AṡGeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density ρB. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially (QGP formed at RHIC — can give further information on the equation of state (EoS) and transport coefficients of the Quark Gluon Plasma (QGP).
Holographic Multiquarks in the Quark-Gluon Plasma: A Review
Directory of Open Access Journals (Sweden)
Piyabut Burikham
2011-01-01
Full Text Available We review the holographic multiquark states in the deconfined quark-gluon plasma. Nuclear matter can become deconfined by extremely high temperature and/or density. In the deconfined nuclear medium, bound states with colour degrees of freedom are allowed to exist. Using holographic approach, the binding energy and the screening length of the multiquarks can be calculated. Using the deconfined Sakai-Sugimoto model, the phase diagram of the multiquark phase, the vacuum phase, and the chiral-symmetric quark-gluon plasma can be obtained. Then we review the magnetic properties of the multiquarks and their phase diagrams. The multiquark phase is compared with the pure pion gradient, the magnetized vacuum, and the chiral-symmetric quark-gluon plasma phases. For moderate temperature and sufficiently large density at a fixed magnetic field, the mixed phase of multiquark and pion gradient is the most energetically preferred phase.
Quark Gluon Plasma: Surprises from strongly coupled QCD matter
Jacak, Barbara
2017-01-01
Quantum Chromodynamics has long predicted a transition from normal hadronic matter to a phase where the quarks and gluons are no longer bound together and can move freely. Quark gluon plasma is now produced regularly in collisions of heavy nuclei at very high energy at both the Relativistic Heavy Ion Collider (RHIC) in the U.S. and at the LHC in Europe. Quark gluon plasma exhibits remarkable properties. Its vanishingly small shear viscosity to entropy density ratio means that it flows essentially without internal friction, making it one of the most ``perfect'' liquids known. It is also very opaque to transiting particles including heavy charm quarks, though the exact mechanism for this is not yet understood. Recent data suggest that even very small colliding systems may produce a droplet of plasma. The similarities to strongly coupled or correlated systems in ultra-cold atoms and condensed matter are striking, and have inspired novel theoretical descriptions growing out of string theory. It remains a mystery how this plasma emerges from cold, dense gluonic matter deep inside nuclei. I will discuss how a future electron-ion collider can help address this question.
Describing the strongly interacting quark-gluon plasma through the Friedberg-Lee model
Shu, Song; Li, Jia-Rong
2010-10-01
The Friedberg-Lee (FL) model is studied at finite temperature and density. The soliton solutions of the FL model in the deconfinement phase transition are solved and thoroughly discussed for certain boundary conditions. We indicate that the solitons before and after the deconfinement have different physical meanings: the soliton before deconfinement represents hadrons, while the soliton after the deconfinement represents the bound state of quarks which leads to a strongly interacting quark-gluon plasma phase. The corresponding phase diagram is given.
Hamieh, Salah; Letessier, Jean; Rafelski, Johann
2000-01-01
Lattice-QCD results provide an opportunity to model, and extrapolate to finite baryon density, the properties of the quark-gluon plasma (QGP). Upon fixing the scale of the thermal coupling constant and vacuum energy to the lattice data, the properties of resulting QGP equations of state (EoS) are developed. We show that the physical properties of the dense matter fireball formed in heavy ion collision experiments at CERN-SPS are well described by the QGP-EoS we presented. We also estimate the...
Equilibration in quark gluon plasma
Das, S. K.; Alam, J.; Mohanty, P.
2011-07-01
The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more realistic EoS keep the partons closer to the equilibrium.
Equilibration in Quark Gluon Plasma
Das, Santosh K.; Alam, Jan-e; Mohanty, Payal
2009-01-01
The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more real...
Equilibration in Quark Gluon Plasma
Das, Santosh K; Mohanty, Payal
2009-01-01
The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more realistic EoS keep the partons closer to the equilibrium.
Hamieh, Salah; Letessier, Jean; Rafelski, Johann
2000-12-01
Lattice quantum chromodynamics results provide an opportunity to model, and extrapolate to finite baryon density, the properties of the quark-gluon plasma (QGP). Upon fixing the scale of the thermal coupling constant and vacuum energy to the lattice data, the properties of resulting QGP equations of state (EoS) are developed. We show that the physical properties of the dense matter fireball formed in heavy ion collision experiments at CERN-SPS are well described by the QGP-EoS we presented. We also estimate the properties of the fireball formed in early stages of nuclear collision, and argue that QGP formation must be expected down to 40A GeV in central Pb-Pb interactions.
Holographic quark-gluon plasmas at finite quark density
Energy Technology Data Exchange (ETDEWEB)
Bigazzi, F. [Dipartimento di Fisica e Astronomia, Universita di Firenze, Sesto Fiorentino (Firenze), Pisa (Italy); INFN, Sezione di Torino (Italy); Cotrone, A. [Dipartimento di Fisica, Universita di Torino (Italy); Mas, J. [Departamento de Fisica de Particulas, Universidade de Santiago de Compostela (Spain); Instituto Galego de Fisica de Altas Enerxias (IGFAE), Santiago de Compostela (Spain); Tarrio, J. [Institute for Theoretical Physics and Spinoza Institute, Universiteit Utrecht, 3584 CE, Utrecht (Netherlands); Mayerson, D. [Institute for Theoretical Physics, University of Amsterdam (Netherlands)
2012-07-15
Gravity solutions holographically dual to strongly coupled quark-gluon plasmas with non-zero quark density are reviewed. They are motivated by the urgency of finding novel tools to explore the phase diagram of QCD-like theories at finite chemical potential. After presenting the solutions and their regime of validity, some of their physical properties are discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
HUNTING THE QUARK GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
LUDLAM, T.; ARONSON, S.
2005-04-11
matter at extremely high density and temperature--a medium in which the predictions of QCD can be tested, and new phenomena explored, under conditions where the relevant degrees of freedom, over nuclear volumes, are expected to be those of quarks and gluons, rather than of hadrons. This is the realm of the quark gluon plasma, the predicted state of matter whose existence and properties are now being explored by the RHIC experiments.
Heavy Ions at LHC: A Quest for Quark-Gluon Plasma
Bhalerao, Rajeev S
2008-01-01
Quantum Chromo Dynamics (QCD), the theory of strong interactions, predicts a transition of the usual matter to a new phase of matter, called Quark-Gluon Plasma (QGP), at sufficiently high temperatures. The non-perturbative technique of defining a theory on a space-time lattice has been used to obtain this and other predictions about the nature of QGP. Heavy ion collisions at the Large Hadron Collider in CERN can potentially test these predictions and thereby test our theoretical understanding of confinement. This brief review aims at providing a glimpse of both these aspects of QGP.
Flow at the SPS and RHIC as a Quark Gluon Plasma Signature
Teaney, D.; LAURET, J.; Shuryak, E. V.
2000-01-01
Radial and elliptic flow in non-central heavy ion collisions can constrain the effective Equation of State(EoS) of the excited nuclear matter. To this end, a model combining relativistic hydrodynamics and a hadronic transport code(RQMD [17]) is developed. For an EoS with a first order phase transition, the model reproduces both the radial and elliptic flow data at the SPS. With the EoS fixed from SPS data, we quantify predictions at RHIC where the Quark Gluon Plasma(QGP) pressure is expected ...
Smilga, A V
1997-01-01
In this lecture, we give a brief review of what theorists now know, understand, or guess about static and kinetic properties of quark--gluon plasma. A particular attention is payed to the problem of physical observability, i.e. the physical meaningfulne ss of various characteristics of QGP discussed in the literature.
Baryon Ratios in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
MA Zhong-Biao; MIAO Hong; GAO Chong-Shou
2003-01-01
A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavyion collisionsis presented. It is assumed that at the beginning of the hadronization there are diquarks and anti-diquarks in the quarkmatter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays aretaken into account. The results are shown at last.
Bag model of hadrons, dual QCD thermodynamics and Quark-Gluon Plasma
Chandola, H C; Dehnen, H
2015-01-01
Using the grand canonical ensemble formulation of a multi-particle statistical system, the thermodynamical description of the dual QCD has been presented in terms of the bag model of hadrons and analyzed for the quark-gluon plasma phase of hadronic matter. The dual QCD bag construction has been shown to lead to the radial pressure on the bag surface in terms of the vector glueball masses of the magnetically condensed QCD vacuum. Constructing the grand canonical partition function to deal with the quark-gluon plasma phase of the non-strange hadrons, the energy density and the plasma pressure have been derived and used to understand the dynamics of the associated phase transition. The critical temperature for QGP-hadron phase transition has been derived and numerically estimated by using various thermodynamic considerations. A comparison of the values of the critical temperatures for QGP-hadron phase transition with those obtained for the deconfinement-phase transition, has been shown to lead to the relaxation ...
Colliding solitary waves in quark gluon plasmas
Rafiei, Azam; Javidan, Kurosh
2016-09-01
We study the head-on collision of propagating waves due to perturbations in quark gluon plasmas. We use the Massachusetts Institute of Technology bag model, hydrodynamics equation, and suitable equation of state for describing the time evolution of such localized waves. A nonlinear differential equation is derived for the propagation of small amplitude localized waves using the reductive perturbation method. We show that these waves are unstable and amplitude of the left-moving (right-moving) wave increases (decreases) after the collision, and so they reach the borders of a quark gluon plasma fireball with different amplitudes. Indeed we show that such arrangements are created because of the geometrical symmetries of the medium.
Strongly Coupled Quark Gluon Plasma (SCQGP)
Bannur, V M
2006-01-01
We propose that the reason for the non-ideal behavior seen in lattice simulation of quark gluon plasma (QGP) and relativistic heavy ion collisions (URHICs) experiments is that the QGP near T_c and above is strongly coupled plasma (SCP), i.e., strongly coupled quark gluon plasma (SCQGP). It is remarkable that the widely used equation of state (EoS) of SCP in QED (quantum electrodynamics) very nicely fits lattice results on all QGP systems, with proper modifications to include color degrees of freedom and running coupling constant. Results on pressure in pure gauge, 2-flavors and 3-flavors QGP, are all can be explained by treating QGP as SCQGP as demonstated here.Energy density and speed of sound are also presented for all three systems.
Energy Density in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
马忠彪; 苗洪; 高崇寿
2003-01-01
We study the energy density in quark-gluon plasma. At the very high temperature, the quark matter is a hot and dense matter in the colour deconfinement condition, and quarks can coalescent diquarks. Energy density of this system is worked out and compared with the energy density in the other two kinds of situations. Possible energy density is about eo ≈ 2.4 GeV/fm3 according to our estimation for quark matter including diquarks,
Hadrons and Quark-Gluon Plasma
Letessier, Jean; Rafelski, Johann
2002-06-01
Before matter as we know it emerged, the universe was filled with the primordial state of hadronic matter called quark gluon plasma. This hot soup of quarks and gluon is effectively an inescapable consequence of our current knowledge about the fundamental hadronic interactions, quantum chromodynamics. This book covers the ongoing search to verify this prediction experimentally and discusses the physical properties of this novel form of matter.
On the quark-gluon plasma search
Hamieh, S. D.
2004-01-01
We report on the effect of the quantum statistics on the two-proton spin correlation (SC) in cold and thermal nuclear matter. We have found that two nucleons SC function can be well approximated by a guassian with correlations length $\\sigma\\sim1.2$ fm. We have proposed SC measurement on low protons energy as test of the quark-gluon plasma formation in relativistic heavy ions collisions.
Linear Landau damping in strongly relativistic quark gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Murtaza, G.; Khattak, N.A.D.; Shah, H.A. [Salam Chair in Physics, G C Univ., Lahore (Pakistan)]|[Dept. of Physics, G C Univ., Lahore (Pakistan)
2004-07-01
On the basis of semi classical kinetic Vlasov equation for Quark-Gluon plasma (QGP) and Yang-Mills equation in covariant gauge, linear Landau damping for electrostatic perturbations like Langmuir waves is investigated. For the extreme relativistic case, wherein the thermal speed of the particles exceeds the phase velocity of the perturbations, the linear Landau damping is absent. However, a departure from extreme relativistic case generates an imaginary component of the frequency giving rise to linear Landau damping effect. The relevant integral for the conductivity tensor has been evaluated and the dispersion relation for the longitudinal part of the oscillation obtained. (orig.)
Electromagnetic signals of quark gluon plasma
Indian Academy of Sciences (India)
Bikash Sinha
2000-04-01
Successive equilibration of quark degrees of freedom and its effects on electromagnetic signals of quark gluon plasma are discussed. The effects of the variation of vector meson masses and decay widths on photon production from hot strongly interacting matter formed after Pb + Pb and S + Au collisions at CERN SPS energies are considered. It has been shown that the present photon spectra measured by WA80 and WA98 Collaborations can not distinguish between the formation of quark matter and hadronic matter in the initial state.
Collective flow signals the quark-gluon plasma
Stöcker, H.
2005-03-01
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A GeV: here the hydrodynamic model has predicted the collapse of the v-flow and of the v-flow at ˜10 A GeV; at 40 A GeV it has been recently observed by the NA49 Collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as evidence for a first order phase transition at high baryon density ρ. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Here, hadronic rescattering models can explain 2 GeV/c. This is interpreted as evidence for the production of superdense matter at RHIC with initial pressure far above hadronic pressure, p>1 GeV/fm. We suggest that the fluctuations in the flow, v and v, should be measured in future since ideal hydrodynamics predicts that they are larger than 50% due to initial state fluctuations. Furthermore, the QGP coefficient of viscosity may be determined experimentally from the fluctuations observed. The connection of v to jet suppression is examined. It is proven experimentally that the collective flow is not faked by minijet fragmentation. Additionally, detailed transport studies show that the away-side jet suppression can only partially (QGP formed at RHIC—can give further information on the equation of state (EoS) and transport coefficients of the quark-gluon plasma (QGP).
In-medium effects in the holographic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Rust, Felix Christian
2009-08-05
In this dissertation we use the gauge/gravity duality to investigate various properties of strongly coupled gauge theories, which we interpret as models for the quark-gluon plasma (QGP). In particular, we use variants of the D3/D7 setup as an implementation of the top-down approach of connecting string theory with phenomenologically relevant gauge theories. We focus on the effects of finite temperature and finite density on fundamental matter in the holographic quark-gluon plasma, which we model as the N = 2 hypermultiplet in addition to the N=4 gauge multiplet of supersymmetric Yang-Mills theory. As a key ingredient we develop a setup in which we can describe vector meson spectra in the holographic plasma at finite temperature and either baryon or isospin density. The description of vector meson excitations allows for a demonstration of the splitting of their spectrum at finite isospin chemical potential. In the effort to better understand transport processes in the QGP, we then study various diffusion coefficients in the quark-gluon plasma, including their dependence on temperature and particle density. In particular, we perform a simple calculation to obtain the diffusion coefficient of baryon charge and we derive expressions to obtain the isospin diffusion coefficient. Furthermore, we make use of an effective model to study the diffusion behavior of mesons in the plasma by setting up a kinetic model. Finally, we observe the implications of finite temperature and finite baryon or isospin density on the phase structure of fundamental matter in the holographic plasma. As one consequence we find a phase transition in the baryon diffusion coefficient which vanishes at a critical value of the particle density. The critical density we quantify matches the values of the according critical densities previously found in the phase transitions of other quantities. More important, we observe a new phase transition occurring when the isospin chemical potential excesses a
Niemi, H; Denicol, G S; Huovinen, P; Molnár, E; Rischke, D H
2011-05-27
We investigate the influence of a temperature-dependent shear viscosity over entropy density ratio η/s on the transverse momentum spectra and elliptic flow of hadrons in ultrarelativistic heavy-ion collisions. We find that the elliptic flow in √S(NN)=200 GeV Au+Au collisions at RHIC is dominated by the viscosity in the hadronic phase and in the phase transition region, but largely insensitive to the viscosity of the quark-gluon plasma (QGP). At the highest LHC energy, the elliptic flow becomes sensitive to the QGP viscosity and insensitive to the hadronic viscosity.
QCD equations of state and the quark-gluon plasma liquid model
Letessier, Jean; Rafelski, Johann
2003-03-01
Recent advances in the study of equations of state of thermal lattice quantum chromodynamics obtained at nonzero baryon density allow validation of the quark-gluon plasma (QGP) liquid model equations of state (EOS). We study here the properties of the QGP-EOS near to the phase transformation boundary at finite baryon density and show a close agreement with the lattice results.
Pion interferometry at RHIC: porobing a thermalized quark-gluon plasma?
Soff, S; Bass, S A; Dumitru, A
2001-04-30
We calculate the Gaussian radius parameters of the pion-emitting source in high-energy heavy-ion collisions, assuming a first-order phase transition from a thermalized quark-gluon plasma (QGP) to a gas of hadrons. Such a model leads to a very long-lived dissipative hadronic rescattering phase which dominates the properties of the two-pion correlation functions. The radii are found to depend only weakly on the thermalization time tau(i), the critical temperature Tc (and thus the latent heat), and the specific entropy of the QGP. The model calculations suggest a rapid increase of R(out)/R(side) as a function of KT if a thermalized QGP were formed.
Exploding Quark-Gluon Plasma Fireball
Hamieh, S; Rafelski, Johann; Hamieh, Salah; Letessier, Jean; Rafelski, Johann
2000-01-01
Lattice-QCD results provide an opportunity to model and extrapolate to finite baryon density the properties of the quark-gluon plasma (QGP). Upon fixing the scale of the thermal coupling constant and vacuum energy to the lattice data the properties of resulting QGP equations of state (EoS) are developed. An exploding dense matter fireball formed in heavy ion collision experiments at CERN-SPS is considered, and we show that its physical properties are well described by the QGP-EoS we presented. We quantitatively determine the conditions of sudden breakup of the fireball, and show that this instability point is consistent with with the hadronization condition derived from the hadronic particle production data. We further estimate the properties of the fireball as it is formed just after nuclear collision is completed and show that QGP formation must be expected down to 40$A$ GeV central Pb--Pb interactions.
Plasmons in Anisotropic Quark-Gluon Plasma
Carrington, Margaret E; Mrowczynski, Stanislaw
2014-01-01
Plasmons of quark-gluon plasma - gluon collective modes - are systematically studied. The plasma is, in general, non-equilibrium but homogeneous. We consider anisotropic momentum distributions of plasma constituents which are obtained from the isotropic one by stretching or squeezing in one direction. This leads to prolate or oblate distributions, respectively. We study all possible degrees of one dimensional deformation from the extremely prolate case, when the momentum distribution is infinitely elongated in one direction, to the extremely oblate distribution, which is infinitely squeezed in the same direction. In between these extremes we discuss arbitrarily prolate, weakly prolate, isotropic, weakly oblate and arbitrarily oblate distributions. For each case, the number of modes is determined using a Nyquist analysis and the complete spectrum of plasmons is found analytically if possible, and numerically when not. Unstable modes are shown to exist in all cases except that of isotropic plasma. We derive con...
Physics of the quark - gluon plasma
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-09-01
This document gathers 31 contributions to the workshop on the physics of quark-gluon plasma that took place in Palaiseau in september 2001: 1) gamma production in heavy collisions, 2) BRAHMS, 3) experimental conference summary, 4) modelling relativistic nuclear collisions, 5) microscopic reaction dynamics at SPS and RHIC, 6) direct gamma and hard scattering at SPS, 7) soft physics at RHIC, 8) results from the STAR experiment, 9) quarkonia: experimental possibilities, 10) elliptic flow measurements with PHENIX, 11) charmonium production in p-A collisions, 12) anisotropic flow at the SPS and RHIC, 13) deciphering the space-time evolution of heavy ion collisions with correlation measurements, 14) 2-particle correlation at RHIC, 15) particle spectra at AGS, SPS and RHIC, 16) strangeness production in STAR, 17) strangeness production in Pb-Pb collisions at SPS, 18) heavy ion physics at CERN after 2000 and before LHC, 19) NEXUS guideline and theoretical consistency, 20) introduction to high p{sub T} physics at RHIC, 21) a novel quasiparticle description of the quark-gluon plasma, 22) dissociation of excited quarkonia states, 23) high-mass dimuon and B {yields} J/{psi} production in ultrarelativistic heavy ion collisions, 24) strange hyperon production in p + p and p + Pb interactions from NA49, 25) heavy quarkonium hadron cross-section, 26) a new method of flow analysis, 27) low mass dilepton production and chiral symmetry restoration, 28) classical initial conditions for nucleus-nucleus collisions, 29) numerical calculation of quenching weights, 30) strangeness enhancement energy dependence, and 31) heavy quarkonium dissociation.
Flow at the SPS and RHIC as a Quark Gluon Plasma Signature
Teaney, D; Shuryak, E V
2001-01-01
Radial and elliptic flow in non-central heavy ion collisions can constrain the effective Equation of State(EoS) of the excited nuclear matter. To this end, a model combining relativistic hydrodynamics and a hadronic transport code(RQMD [17]) is developed. For an EoS with a first order phase transition, the model reproduces both the radial and elliptic flow data at the SPS. With the EoS fixed from SPS data, we quantify predictions at RHIC where the Quark Gluon Plasma(QGP) pressure is expected to drive additional radial and elliptic flow. Currently, the strong elliptic flow observed in the first RHIC measurements does not conclusively signal this nascent QGP pressure. Additional measurements are suggested to pin down the EoS.
Flow at the SPS and RHIC as a Quark-Gluon Plasma Signature
Teaney, D.; Lauret, J.; Shuryak, E. V.
2001-05-01
Radial and elliptic flow in noncentral heavy-ion collisions can constrain the effective equation of state (EOS) of the excited nuclear matter. To this end, a model combining relativistic hydrodynamics and a hadronic transport code [Sorge, Phys. Rev. C 52, 3291 (1995)] is developed. For an EOS with a first-order phase transition, the model reproduces both the radial and elliptic flow data at the SPS. With the EOS fixed from SPS data, we quantify predictions at RHIC where the quark-gluon plasma (QGP) pressure is expected to drive additional radial and elliptic flows. Currently, the strong elliptic flow observed in the first RHIC measurements does not conclusively signal this nascent QGP pressure.
Quantum Gravity effect on the Quark-Gluon Plasma
Elmashad, I; Abou-Salem, L I; Nabi, Jameel-Un; Tawfik, A
2012-01-01
The Generalized Uncertainty Principle (GUP), which has been predicted by various theories of quantum gravity near the Planck scale is implemented on deriving the thermodynamics of ideal Quark-Gluon Plasma (QGP) consisting of two massless quark flavors at the hadron-QGP phase equilibrium and at a vanishing chemical potential. The effective degrees of freedom and MIT bag pressure are utilized to distinguish between the hadronic and partonic phases. We find that GUP makes a non-negligible contribution to all thermodynamic quantities, especially at high temperatures. The asymptotic behavior of corresponding QGP thermodynamic quantities characterized by the Stephan-Boltzmann limit would be approached, when the GUP approach is taken into consideration.
Initial energy density of quark-gluon plasma in relativistic heavy-ion collisions
Energy Technology Data Exchange (ETDEWEB)
Wong, C.Y.
1984-01-01
Recently, there has been considerable interest in the central rapidity region of highly relativistic heavy-ion collisions. Such an interest stems from the possibility of creating hadron matter of high energy density which may exceed the critical energy density for a phase transition between ordinary confined matter and the unconfined quark-gluon plasma. The experimental searches and identification of the quark-gluon plasma may provide a new insight into the question of quark confinement. The estimate of the initial energy density is quite uncertain. The initial energy density is nonetheless an important physical quantity. It is one of the factors which determines whether the produced matter can undergo phase transition or not. The energy density has been estimated previously by using the color neutralization model of Brodsky et al. However, the color neutralization model gives a central rapidity multiplicity in heavy-ion collision too low by a factor of two. For this reason, we wish to obtain a better estimate of the energy density (in the central rapidity region). As is well known, a simple Glauber-type multiple collision model can reproduce the total multiplicity and multiplicity plateau near the central rapidity region to within 30%. The simple multiple collision model has an approximate validity as a gross description of the reaction process. We shall adopt a semiempirical approach. Using the multiple collision model and the thickness function of Glauber, we obtain analytical functional form for all the quantities in question. A single parameter, r/sub rms/, is adjusted to fit the experimental central rapidity multiplicity data. The semi-empirical results provide a useful tool to extrapolate to the unknown central rapidity region of heavy-ion collisions.
Chiral superfluidity of the quark-gluon plasma
Kalaydzhyan, Tigran
2013-01-01
In this paper we argue that the strongly coupled quark-gluon plasma can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use several nonperturbative techniques to demonstrate that. First, we analyze the fermionic spectrum in the deconfinement phase (Tc < T < 2 Tc) using lattice (overlap) fermions and observe a gap between near-zero modes and the bulk of the spectrum. Second, we use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Third, we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the "superfluid" component gives rise to the chiral magnetic, c...
Tetraquarks Production in Quark-Gluon Plasma with Diquarks
Institute of Scientific and Technical Information of China (English)
MA Zhong-Biao; GAO Chong-Shou
2006-01-01
@@ We present a way to calculate tetraquarks ratios for quark-gluon plasma with diquarks. The ratios of tetraquarks over baryons produced from quark matter are high than hadronic gas model limits. It is a better way to search for four-quark states in relativistic heavy ion collisions. It may become a criterion to judge whether quark-gluon plasma has formed to search for four-quark states in relativistic heavy ion collisions.
Strangeness Production in a Chemically Equilibrating Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
HE Ze-Jun; LONG Jia-Li; MA Yu-Gang; MA Guo-Liang
2004-01-01
@@ We study the strangeness of a chemically equilibrating quark-gluon plasma at finite baryon density based on the and will accelerate with the change of the initial system from a chemically non-equilibrated to an equilibrated system. We also find that the calculated strangeness is very different from the one in the thermodynamic equilibrium system. This study may be helpful to understand the formation of quark-gluon plasma via a chemically non-equilibrated evolution framework.
Modeling Quark Gluon Plasma Using CHIMERA
Abelev, Betty
2011-09-01
We attempt to model Quark Gluon Plasma (QGP) evolution from the initial Heavy Ion collision to the final hadronic gas state by combining the Glauber model initial state conditions with eccentricity fluctuations, pre-equilibrium flow, UVH2+1 viscous hydrodynamics with lattice QCD Equation of State (EoS), a modified Cooper-Frye freeze-out and the UrQMD hadronic cascade. We then evaluate the model parameters using a comprehensive analytical framework which together with the described model we call CHIMERA. Within our framework, the initial state parameters, such as the initial temperature (Tinit), presence or absence of initial flow, viscosity over entropy density (η/S) and different Equations of State (EoS), are varied and then compared simultaneously to several experimental data observables: HBT radii, particle spectra and particle flow. χ2/nds values from comparison to the experimental data for each set of initial parameters will then used to find the optimal description of the QGP with parameters that are difficult to obtain experimentally, but are crucial to understanding of the matter produced.
Modeling Quark Gluon Plasma Using CHIMERA
Abelev, Betty B I
2011-01-01
We attempt to model Quark Gluon Plasma (QGP) evolution from the initial Heavy Ion collision to the final hadronic gas state by combining the Glauber model initial state conditions with eccentricity fluctuations, pre-equilibrium flow, UVH2+1 viscous hydrodynamics with lattice QCD Equation of State (EoS), a modified Cooper-Frye freeze-out and the UrQMD hadronic cascade. We then evaluate the model parameters using a comprehensive analytical framework which together with the described model we call CHIMERA. Within our framework, the initial state parameters, such as the initial temperature (T$_{\\mathrm{init}}$), presence or absence of initial flow, viscosity over entropy density ($\\eta$/s) and different Equations of State (EoS), are varied and then compared simultaneously to several experimental data observables: HBT radii, particle spectra and particle flow. $\\chi^2$/nds values from comparison to the experimental data for each set of initial parameters will then used to find the optimal description of the QGP wi...
Signals of the QGP phase transition - a view from microscopic transport models
Bratkovskaya, E L
2007-01-01
In this contribution the results from various transport models on different observables - considered as possible signals of the phase transition from hadronic matter to the quark-gluon plasma (QGP) - are briefly reviewed.
Effective degrees of freedom of the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Castorina, P. [Dipartimento di Fisica, Universita di Catania, and INFN Sezione di Catania, Via Santa Sofia 64, I-95100 Catania (Italy); Mannarelli, M. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)]. E-mail: massimo@lns.mit.edu
2007-01-25
The effective degrees of freedom of the quark-gluon plasma are studied in the temperature range {approx}(1-2)T{sub c}. We show that including light bosonic states one can reproduce the pressure and energy density of the quark-gluon plasma obtained by lattice simulations. The number of the bosonic states required is at most of the order of 20, consistent with the number of light mesonic states and in disagreement with a recently proposed picture of the quark-gluon plasma as a system populated with exotic bound states. We also constrain the quark quasiparticle chiral invariant mass to be {approx}300 MeV. Some remarks regarding the role of the gluon condensation and the baryon number-strangeness correlation are also presented.
Anomalous Viscosity of the Quark-Gluon Plasma
Hong, Juhee
2013-01-01
The shear viscosity of the quark-gluon plasma is predicted to be lower than the collisional viscosity for weak coupling. The estimated ratio of the shear viscosity to entropy density is rather close to the ratio calculated by N = 4 super Yang-Mills theory for strong coupling, which indicates that the quark-gluon plasma might be strongly coupled. However, in presence of momentum anisotropy, the Weibel instability can arise and affect transport properties. Shear viscosity can be lowered by enhanced collisionality due to turbulence, but the decorrelation time and its relation to underlying dynamics and color-magnetic fields have not been calculated self-consistently. In this paper, we use resonance broadening theory for strong turbulence to calculate the anomalous viscosity of the quark-gluon plasma for nonequilibrium. For saturated Weibel instability, we estimate the scalings of the decorrelation rate and viscosity and compare these with collisional transport. This calculation yields an explicit connection betw...
The refractive index in the viscous quark-gluon plasma
Jiang, Bing-feng; Li, Jia-rong; Gao, Yan-Jun
2013-01-01
Under the framework of the viscous chromohydrodynamics, the gluon self-energy is derived for the quark-gluon plasma with shear viscosity. The viscous electric permittivity and magnetic permeability are evaluated from the gluon self-energy, through which the refraction index %in the %viscous quark-gluon plasma is investigated. The numerical analysis indicates that the refractive index becomes negative in some frequency range. The start point for that frequency range is around the electric permittivity pole, and the magnetic permeability pole determines the end point. As the increase of $\\eta/s$, the frequency range for the negative refraction becomes wider.
Takahashi, Y.; Eby, P. B.
1985-01-01
Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.
Phenomenological aspects of an anisotropic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Martinez Guerrero, Mauricio
2010-04-30
In this work we investigate phenomenological aspects of an anisotropic quark-gluon plasma. In the first part of this thesis, we formulate phenomenologicalmodels that take into account the momentumspace anisotropy of the system developed during the expansion of the fireball at early-times. By including the proper-time dependence of the parton hard momentum scale, p{sub hard}({tau}), and the plasma anisotropy parameter, {xi}({tau}), the proposed models allow us to interpolate from 0+1 pre-equilibrated expansion at early-times to 0+1 ideal hydrodynamics at late times. We study dilepton production as a valuable observable to experimentally determine the isotropization time of the system as well as the degree of anisotropy developed at early-times. We generalize our interpolating models to include the rapidity dependence of p{sub hard} and consider its impact on forward dileptons. Next, we discuss how to constrain the onset of hydrodynamics by demanding two requirements of the solutions to the equations of motion of viscous hydrodynamics. We show this explicitly for 0+1 dimensional 2nd-order conformal viscous hydrodynamics and find that the initial conditions are non-trivially constrained. Finally, we demonstrate how to match the initial conditions for 0+1 dimensional viscous hydrodynamics from pre-equilibrated expansion. We analyze the dependence of the entropy production on the pre-equilibrium phase and discuss limitations of the standard definitions of the non-equilibrium entropy in kinetic theory. (orig.)
Bleicher, M; Bleicher, Marcus
2005-01-01
The excitation function of the in-plane directed flow of nucleons is studied within a non-equilibrium transport approach. It is demonstrated that a local minimum in the excitation function of the directed flow develops, which is not related to a transition into a quark-gluon plasma (QGP) phase. It is a consequence of the dynamical softening of the underlying equation of state, due to the onset of resonance matter and particle production. Thus, the interpretation of this minimum as a 'smoking gun' signature for the creation of a QGP is premature.
Effect of curvature on a statistical model of quark-gluon-plasma fireball in the hadronic medium
Indian Academy of Sciences (India)
S Somorendro Singh; D S Gosain; Yogesh Kumar; Agam K Jha
2010-01-01
The free energy of a quark-gluon plasma fireball in the hadronic medium is calculated in the Ramanathan et al statistical model after incorporating the effect of curvature. The result with the inclusion of curvature is found to produce significant improvements in all the parameters we calculated with respect to the earlier results. The surface tension with this curvature effect is found to be $0.17 T_{c}^{3}$ , which is two times the earlier value of surface tension which is $0.078 T_{c}^{3}$ , and this new result is nearly close to the lattice value $0.24 T_{c}^{3}$. As far as transition is concerned, a thermodynamic variable like entropy shows weakly first-order phase transition and it shows continuity in the behaviour of specific heat.
Quark and Gluon Relaxation in Quark-Gluon Plasmas
Heiselberg, H.; Pethick, C. J.
1993-01-01
The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.
Quark and Gluon Relaxation in Quark-Gluon Plasmas
Heiselberg, H.; Pethick, C. J.
1993-01-01
The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.
The quark gluon plasma: Lattice computations put to experimental test
Indian Academy of Sciences (India)
Sourendu Gupta
2003-11-01
I describe how lattice computations are being used to extract experimentally relevant features of the quark gluon plasma. I deal speciﬁcally with relaxation times, photon emissivity, strangeness yields, event-by-event ﬂuctuations of conserved quantities and hydrodynamic ﬂow. Finally I give evidence that the plasma is rather liquid-like in some ways.
Nonlinear Landau damping in quark-gluon plasma
Xiaofei, Zhang; Jiarong, Li
1995-08-01
The semiclassical kinetic equations for the quark-gluon plasma (QGP) are discussed by the multiple time-scale method. The mechanism of nonlinear Landau damping owing to non-Abelian and nonlinear wave-particle interactions in QGP is investigated, and the nonlinear Landau damping rate for the longitudinal color eigenwaves in the long-wavelength limit is calculated.
Holographic Wilson loops in anisotropic quark-gluon plasma.
Ageev, Dmitry
2016-10-01
The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
Holographic Wilson loops in anisotropic quark-gluon plasma.
Directory of Open Access Journals (Sweden)
Ageev Dmitry
2016-01-01
Full Text Available The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
On magnetization of quark-gluon plasma at the LHC experiment energies
Skalozub, V
2016-01-01
Large scale chromomagnetic, B_3, B_8, and usual magnetic,H, fields have to be generated in QCD after the deconfinement phase transition (DPT) at temperatures T larger than deconfinement temperature T_d. The two former fields are created spontaneously due to asymptotic freedom of gluon intaractions. Whereas H is produced due to either the feature of quarks to possess both electric and color charges or a vacuum polarization in this case. At the polarization, the vacuum quark loops mix the external fields. As a result, B_3, B_8 become the sources generating H. The latter field appears at $T$ much lower than the electroweak phase transition temperature T_ew. This mechanism should exhibit itself at the LHC experiments on heavy ion collisions. It operates at the one-loop diagram level for an effective potential. The created fields are temperature dependent and occupying the macroscopic volume of quark-gluon plasma. The magnetization influences different processes and may serve as a signal for the DPT.
Properties of the quark gluon plasma from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Mages, Simon Wolfgang
2015-03-02
Quantum Chromodynamics (QCD) is the theory of the strong interaction, the theory of the interaction between the constituents of composite elementary particles (hadrons). In the low energy regime of the theory, standard methods of theoretical physics like perturbative approaches break down due to a large value of the coupling constant. However, this is the region of most interest, where the degrees of freedom of QCD, the color charges, form color-neutral composite elementary particles, like protons and neutrons. Also the transition to more energetic states of matter like the quark gluon plasma (QGP), is difficult to investigate with perturbative approaches. A QGP is a state of strongly interacting matter, which existed shortly after the Big Bang and can be created with heavy ion collisions for example at the LHC at CERN. In a QGP the color charges of QCD are deconfined. This thesis explores ways how to use the non-perturbative approach of lattice QCD to determine properties of the QGP. It focuses mostly on observables which are derived from the energy momentum tensor, like two point correlation functions. In principle these contain information on low energy properties of the QGP like the shear and bulk viscosity and other transport coefficients. The thesis describes the lattice QCD simulations which are necessary to measure the correlation functions and proposes new methods to extract these low energy properties. The thesis also tries to make contact to another non-perturbative approach which is Improved Holographic QCD. The aim of this approach is to use the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence to make statements about QCD with calculations of a five dimensional theory of gravity. This thesis contributes to that work by constraining the parameters of the model action by comparing the predictions with those of measurements with lattice QCD.
Suppression of Baryon Diffusion and Transport in a Baryon Rich Strongly Coupled Quark-Gluon Plasma.
Rougemont, Romulo; Noronha, Jorge; Noronha-Hostler, Jacquelyn
2015-11-13
Five dimensional black hole solutions that describe the QCD crossover transition seen in (2+1)-flavor lattice QCD calculations at zero and nonzero baryon densities are used to obtain predictions for the baryon susceptibility, baryon conductivity, baryon diffusion constant, and thermal conductivity of the strongly coupled quark-gluon plasma in the range of temperatures 130 MeV≤T≤300 MeV and baryon chemical potentials 0≤μ(B)≤400 MeV. Diffusive transport is predicted to be suppressed in this region of the QCD phase diagram, which is consistent with the existence of a critical end point at larger baryon densities. We also calculate the fourth-order baryon susceptibility at zero baryon chemical potential and find quantitative agreement with recent lattice results. The baryon transport coefficients computed in this Letter can be readily implemented in state-of-the-art hydrodynamic codes used to investigate the dense QGP currently produced at RHIC's low energy beam scan.
Energy loss, equilibration, and thermodynamics of a baryon rich strongly coupled quark-gluon plasma
Rougemont, Romulo; Finazzo, Stefano; Noronha, Jorge
2015-01-01
Lattice data for the QCD equation of state and the baryon susceptibility near the crossover phase transition (at zero baryon density) are used to determine the input parameters of a 5-dimensional Einstein-Maxwell-Dilaton holographic model that provides a consistent holographic framework to study both equilibrium and out-of-equilibrium properties of a hot and {\\it baryon rich} strongly coupled quark-gluon plasma (QGP). We compare our holographic equation of state computed at nonzero baryon chemical potential, $\\mu_B$, with recent lattice calculations and find quantitative agreement for the pressure and the speed of sound for $\\mu_B \\leq 400$ MeV. This holographic model is used to obtain holographic predictions for the temperature and $\\mu_B$ dependence of the drag force and the Langevin diffusion coefficients associated with heavy quark jet propagation as well as the jet quenching parameter $\\hat{q}$ and the shooting string energy loss of light quarks in the dense plasma. We find that the energy loss of heavy ...
A rotation/magnetism analogy for the quark-gluon plasma
McInnes, Brett
2016-10-01
In peripheral heavy ion collisions, the Quark-Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local) rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential) which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.
Quark-gluon plasma in strong magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Kalaydzhyan, Tigran
2013-04-15
One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.
Photon production from quark gluon plasma at ﬁnite baryon density
Indian Academy of Sciences (India)
D Dutta; S V S Sastry; A K Mohanty; K Kumar; R K Choudhury
2003-05-01
The photon yield from a baryon-rich quark gluon plasma (QGP) at SPS energy has been estimated. In the QGP phase, rate of photon production is evaluated up to two-loop level. In the hadron phase, dominant contribution from , , mesons has been considered. The evolution of the plasma has been studied with appropriate equation of state in both QGP and hadron phase for a baryon-rich system. At SPS energy, the total photon yield is found to increase marginally in the presence of baryon density.
The extent of strangeness equilibration in quark gluon plasma
Indian Academy of Sciences (India)
Dipali Pal; Abhijit Sen; Munshi Golam Mustafa; Dinesh Kumar Srivastava
2003-05-01
The evolution and production of strangeness from chemically equilibrating and transversely expanding quark gluon plasma which may be formed in the wake of relativistic heavy-ion collisions is studied with initial conditions obtained from the self screened parton cascade (SSPC) model. The extent of partonic equilibration increases almost linearly with the square of the initial energy density, which can then be scaled with the number of participants.
RHIC AND THE PURSUIT OF THE QUARK-GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
MITCHELL,J.T.
2001-07-25
There is a fugitive on the loose. Its name is Quark-Gluon Plasma, alias the QGP. The QGP is a known informant with knowledge about the fundamental building blocks of nature that we wish to extract. This briefing will outline the status of the pursuit of the elusive QGP. We will cover what makes the QGP tick, its modus operandi, details on how we plan to hunt the fugitive down, and our level of success thus far.
Collective Flow signals the Quark Gluon Plasma
Stöcker, H
2005-01-01
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A$\\cdot$GeV: here the hydrodynamic model has predicted the collapse of the $v_1$-flow and of the $v_2$-flow at $\\sim 10$ A$\\cdot$GeV; at 40 A$\\cdot$GeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density $\\rho_B$. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially ($<$ 50%) be due to hadronic rescattering. We, finally, propose upgrades and second generation experiments at RHIC which inspect the first order phase transition in the fragmenta...
Charmonium states in quark-gluon plasma
Indian Academy of Sciences (India)
Su Houng Lee; Kenji Morita
2009-01-01
We discuss how the spectral changes of quarkonia at c can reflect the `critical' behaviour of QCD phase transition. Starting from the temperature dependencies of the energy density and pressure from lattice QCD calculation, we extract the temperature dependencies of the scalar and spin-2 gluon condensates near c . We also parametrize these changes into the electric and magnetic condensate near c. While the magnetic condensate hardly changes across c, we find that the electric condensate increases abruptly above c. Similar abrupt change is also seen in the scalar condensate. Using the QCD second-order Stark effect and QCD sum rules, we show that these sudden changes induce equally abrupt changes in the mass and width of /, both of which are larger than 100 MeV at slightly above c.
From Color Fields to Quark Gluon Plasma
Fries, R J; Li, Y; Fries, Rainer J.; Kapusta, Joseph I.; Li, Yang
2006-01-01
We discuss a model for the energy distribution and the early space-time evolution of a heavy ion collision. We estimate the gluon field generated in the wake of hard processes and through primordial fluctuations of the color charges in the nuclei. Without specifying the dynamical mechanism of thermalization we calculate the energy momentum tensor of the following plasma phase. The results of this model can be used as initial conditions for a further hydrodynamic evolution.
Quark-gluon plasma and topological quantum field theory
Luo, M. J.
2017-03-01
Based on an analogy with topologically ordered new state of matter in condensed matter systems, we propose a low energy effective field theory for a parity conserving liquid-like quark-gluon plasma (QGP) around critical temperature in quantum chromodynamics (QCD) system. It shows that below a QCD gap which is expected several times of the critical temperature, the QGP behaves like topological fluid. Many exotic phenomena of QGP near the critical temperature discovered at Relativistic Heavy Ion Collision (RHIC) are more readily understood by the suggestion that QGP is a topologically ordered state.
Baryon inhomogeneities in a charged quark gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Ray, Avijeet [Indian Institute of Technology Roorkee, Uttarakhand, 247667 (India); Sanyal, Soma, E-mail: sossp@uohyd.ernet.in [School of Physics, University of Hyderabad, Gachibowli, Hyderabad, 500046 (India)
2013-10-07
We study the generation of baryon inhomogeneities in regions of the quark gluon plasma which have a charge imbalance. We find that the overdensity in the baryon lumps for positively charged particles is different from the overdensity due to the negatively charged particles. Since quarks are charged particles, the probability of forming neutrons or protons in the lumps would thus be changed. The probability of forming hadrons having quarks of the same charges would be enhanced. This might have interesting consequences for the inhomogeneous nucleosynthesis calculations.
Surface Emission of Quark Gluon Plasma at RHIC and LHC
Institute of Scientific and Technical Information of China (English)
XIANG Wen-Chang; WAN Ren-Zhuo; ZHOU Dai-Cui
2008-01-01
Within the framework of a factorization model, we study the behaviour of nuclear modification factor in Au-Au collisions at RHIC and Pb-Pb collisions at LHC. We find that the nuclear modification factor is inversely proportional to the radius of the quark-gluon plasma and is dominated by the surface emission of hard jets. We predict the nuclear modification factor RLHCAA～0.15 in central Pb-Pb collisions at LHC. The study shows that the factorization model can be used to describe the centrality dependence of nuclear modification factor of the high transverse momentum particles produced in heavy ion collisions at both RHIC and LHC.
Working group report: Heavy-ion physics and quark-gluon plasma
Indian Academy of Sciences (India)
Munshi G Mustafa; Sudhir Raniwala; T Awes; B Rai; R S Bhalerao; J G Contreras; R V Gavai; S K Ghosh; P Jaikumar; G C Mishra; A P Mishra; H Mishra; B Mohanty; J Nayak; J-Y Ollitrault; S C Phatak; L Ramello; R Ray; P K Sahu; A M Srivastava; D K Srivastava; V K Tiwari
2006-11-01
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported.
Phenomenological review on Quark-Gluon Plasma: concepts vs observations
Pasechnik, Roman
2016-01-01
In this review, we present an up-to-date phenomenological summary of research developments in physics of the Quark-Gluon Plasma (QGP). A short historical perspective and theoretical motivation for this rapidly developing field of contemporary Particle Physics is provided. In addition, we introduce and discuss the role of the QCD ground state, non-perturbative and lattice QCD results on the QGP properties as well as the transport models used to make a connection between theory and experiment. The experimental part presents the selected results on bulk observables, hard and penetrating probes obtained in the ultra-relativistic heavy-ion experiments carried out at BNL RHIC, CERN SPS and LHC accelerators. We also give a brief overview of new developments related to the ongoing searches of the QCD critical point and to the collectivity in small ($p+p$ and $p+A$) systems.
Color Instabilities in the Quark-Gluon Plasma
Mrowczynski, Stanislaw; Strickland, Michael
2016-01-01
When the quark-gluon plasma (QGP) - a system of deconfined quarks and gluons - is in a nonequilibrium state, it is usually unstable with respect to color collective modes. The instabilities, which are expected to strongly influence dynamics of the QGP produced in relativistic heavy-ion collisions, are extensively discussed under the assumption that the plasma is weakly coupled. We begin by presenting the theoretical approaches to study the QGP, which include: field theory methods based on the Keldysh-Schwinger formalism, classical and kinetic theories, and fluid techniques. The dispersion equations, which give the spectrum of plasma collective excitations, are analyzed in detail. Particular attention is paid to a momentum distribution of plasma constituents which is obtained by deforming an isotropic momentum distribution. Mechanisms of chromoelectric and chromomagnetic instabilities are explained in terms of elementary physics. The Nyquist analysis, which allows one to determine the number of solutions of a ...
Quark-gluon plasma connected to finite heat bath
Energy Technology Data Exchange (ETDEWEB)
Biro, Tamas S.; Gabor Barnafoeldi, Gergely; Van, Peter [Wigner Research Centre for Physics of the HAS, P.O.Box 49, Budapest (Hungary)
2013-09-15
We derive entropy formulas for finite reservoir systems, S{sub q}, from universal thermostat independence and obtain the functional form of the corresponding generalized entropy-probability relation. Our result interprets thermodynamically the subsystem temperature, T{sub 1}, and the index q in terms of the temperature, T, entropy, S, and heat capacity, C of the reservoir as T{sub 1}=T exp (-S/C) and q=1-1/C. In the infinite C limit, irrespective of the value of S, the Boltzmann-Gibbs approach is fully recovered. We apply this framework for the experimental determination of the original temperature of a finite thermostat, T, from the analysis of hadron spectra produced in high-energy collisions, by analyzing frequently considered simple models of the quark-gluon plasma. (orig.)
Quark-gluon plasma: Status of heavy ion physics
Indian Academy of Sciences (India)
R V Gavai
2000-07-01
Lattice quantum chromodynamics (QCD), deﬁned on a discrete space–time lattice, leads to a spectacular non-perturbative prediction of a new state of matter, called quark-gluon plasma (QGP), at sufﬁciently high temperatures or equivalently large energy densities. The experimental programs of CERN, Geneva and BNL, New York of relativistic heavy ion collisions are expected to produce such energy densities, thereby providing us a chance to test the above prediction. After a brief introduction of the necessary theoretical concepts, I will present a critical review of the experimental results already obtained by the various experiments in order to examine whether QGP has already been observed by them.
Photons from quark gluon plasma and hot hadronic matter
Indian Academy of Sciences (India)
Jan-E Alam
2003-04-01
The productions of real photons from quark gluon plasma and hot hadronic matter formed after the nucleus–nucleus collisions at ultra-relativistic energies are discussed. The effects of the spectral shift of the hadrons at ﬁnite temperature on the production of photons are investigated. On the basis of the present analysis it is shown that the photon spectra measured by WA98 collaboration in Pb + Pb collisions at CERN SPS energies can be explained by both QGP as well as hadronic initial states if the spectral shift of hadrons at ﬁnite temperature is taken into account. Several other works on the analysis of WA98 photon data have also been brieﬂy discussed.
From gluon topology to chiral anomaly: Emergent phenomena in quark-gluon plasma
Liao, Jinfeng
2016-01-01
Heavy-ion collision experiments at RHIC and the LHC have found a new emergent phase of QCD, a strongly coupled quark-gluon plasma (sQGP) that is distinctively different from either the low temperature hadron phase or the very high temperature weakly coupled plasma phase. Highly nontrivial emergent phenomena occur in such sQGP and two examples will be discussed in this contribution: the magnetic component of sQGP that stems from topologically nontrivial configurations in the gluon sector; and the anomalous chiral transport that arises as macroscopic manifestation of microscopic chiral anomaly in the quark sector. For both examples, their important roles in explaining pertinent heavy-ion data will be emphasized.
From gluon topology to chiral anomaly: Emergent phenomena in quark-gluon plasma
Liao, Jinfeng
2017-01-01
Heavy-ion collision experiments at RHIC and the LHC have found a new emergent phase of QCD, a strongly coupled quark-gluon plasma (sQGP) that is distinctively different from either the low temperature hadron phase or the very high temperature weakly coupled plasma phase. Highly nontrivial emergent phenomena occur in such sQGP and two examples will be discussed in this contribution: the magnetic component of sQGP that stems from topologically nontrivial configurations in the gluon sector; and the anomalous chiral transport that arises as macroscopic manifestation of microscopic chiral anomaly in the quark sector. For both examples, their important roles in explaining pertinent heavy-ion data will be emphasized.
Hard Photon production from unsaturated quark gluon plasma at two loop level
Dutta, D; Mohanty, A K; Kumar, K; Choudhury, R K
2002-01-01
The hard photon productions from bremsstrahlung and annihilation with scattering that arise at two loop level are estimated from a chemically non-equilibrated quark gluon plasma using the frame work of thermal field theory. Although, the rate of photon production is suppressed due to unsaturated phase space, the above suppression is relatively smaller than expected due to an additional collinear enhancement (arise due to decrease in thermal quark mass) as compared to it's equilibrium counterpart. Interestingly, unlike the one loop case, the reduction in the two loop processes are found to be independent of gluon chemical poential, but strongly depends on quark fugacity. It is also found that, since the phase space suppression is highest for annihilation with scattering, the photon production is entirely dominated by bremsstrahlung mechanism at all energies. This is to be contrasted with the case of the equilibrated plasma where annihilation with scattering dominates the photon production particularly at highe...
Hard photon production from unsaturated quark-gluon plasma at two-loop level
Energy Technology Data Exchange (ETDEWEB)
Dutta, D. E-mail: ddutta@apsara.barc.ernet.in; Sastry, S.V.S.; Mohanty, A.K.; Kumar, K
2002-11-18
The hard photon production from bremsstrahlung and annihilation with scattering that arise at two-loop level are estimated for a chemically non-equilibrated quark-gluon plasma in the framework of Hard Thermal Loop (HTL) resummed effective field theory. The rate of photon production is found to be suppressed due to unsaturated phase space compared to equilibrated plasma. For an unsaturated plasma, unlike the effective one-loop case, the reduction in the effective two-loop processes is found to be independent of gluon fugacity, due to an additional collinear enhancement arising from the decrease in thermal quark mass but strongly depends on quark and antiquark fugacities. It is also found that the photon production is dominated by bremsstrahlung mechanism, since the phase space suppression is higher for annihilation with scattering, in contrast to the equilibrated plasma where annihilation with scattering dominates the photon production.
Heavy-quark transport coefficients in a hot viscous quark-gluon plasma medium
Das, Santosh K; Alam, Jan-e
2012-01-01
The heavy-quark (HQ) transport coefficients have been estimated for a viscous quark-gluon plasma medium, utilizing a recently proposed quasi-particle description based on realistic QGP equation of state (EoS). Interactions entering through the equation of state significantly suppress the temperature dependence of the drag coefficient of QGP as compared to that of an ideal system of quarks and gluons. Inclusion of shear and bulk viscosities through the corrections to the thermal phase space factors of the bath particles alters the magnitude of the drag coefficient and the enhancement is significant at lower temperatures. The competition between the effects of realistic EoS and dissipative corrections through phase space factor the former eventually dictate how the drag coefficient would behave as a function of temperature, and how much quantitatively digress from the ideal case. The observations suggest significant impact of both the realistic equation of state, and the viscosities, on the HQs transport at RHI...
Dileptons from a Chemically Equilibrating Quark-Gluon Plasma at Finite Baryon Density
Institute of Scientific and Technical Information of China (English)
GUAN Na-Na; HE Ze-Jun; LONG Jia-Li; CAI Xiang-Zhou
2008-01-01
We perform a complete calculation for the delepton production from the processes q(q-) →l(l-), Compton-like (qg→ql(l-),(q-)g→ql(l-)), q(q-)→gl(l-), gluon fusion g(g-)→c(c-), annihilation q(q-)→c(c-) as well as multiple scattering of quarks in a chemically equilibrating quark-gluon plasma system at finite baryon density. It is found that quark-antiquark annihilation,Compton-like, gluon fusion and multiple scattering of quarks give important contribution. Moreover, the increase of the quark phase life-time with increasing initial quark chemical potential makes the dilepton yield as an increasing function of the initial quark chemical potential.
Thermodynamics of the Quark-Gluon Plasma within a T-matrix approach
Lacroix, Gwendolyn; Buisseret, Fabien
2015-01-01
The strongly-coupled phase of the quark-gluon plasma (QGP) is studied here by resorting to a $T$-matrix formulation in which the medium is seen as a non-ideal gas of quasiparticles (quarks, antiquarks and gluons) interacting nonpertubatively. In the temperature range under study, (1-5) $T_c$, where $T_c$ is the temperature of deconfinement, the interactions are expected to be strong enough to generate bound states. The dissociation temperature of such binary bound states is thus computed here. The more the quasiparticles involved in the binary system are heavy, the more the bound state is likely to survive significantly above $T_c$. Then, the QGP equations of state at zero and small baryonic potential are computed for $N_f = 2$ and $N_f = 2 + 1$ by resorting to the Dashen, Ma and Bernstein formulation of statistical mechanics. Comparisons with current lattice QCD data are presented.
Some applications of thermal field theory to quark-gluon plasma
Indian Academy of Sciences (India)
Munshi G Mustafa
2006-04-01
We briefly introduce the thermal field theory within imaginary time formalism, the hard thermal loop perturbation theory and some of its applications to the physics of the quark-gluon plasma, possibly created in relativistic heavy-ion collisions.
Strongly coupled quark-gluon plasma in heavy ion collisions
Shuryak, Edward
2017-07-01
A decade ago, a brief summary of the field of the relativistic heavy ion physics could be formulated as the discovery of strongly coupled quark-gluon plasma, sQGP for short, a near-perfect fluid with surprisingly large entropy-density-to-viscosity ratio. Since 2010, the LHC heavy ion program added excellent new data and discoveries. Significant theoretical efforts have been made to understand these phenomena. Now there is a need to consolidate what we have learned and formulate a list of issues to be studied next. Studies of angular correlations of two and more secondaries reveal higher harmonics of flow, identified as the sound waves induced by the initial state perturbations. As in cosmology, detailed measurements and calculations of these correlations helped to make our knowledge of the explosion much more quantitative. In particular, their damping had quantified the viscosity. Other kinetic coefficients—the heavy-quark diffusion constants and the jet quenching parameters—also show enhancements near the critical point T ≈Tc. Since densities of QGP quarks and gluons strongly decrease at this point, these facts indicate large role of nonperturbative mechanisms, e.g., scattering on monopoles. New studies of the p p and p A collisions at high multiplicities reveal collective explosions similar to those in heavy ion A A collisions. These "smallest drops of the sQGP" revived debates about the initial out-of-equilibrium stage of the collisions and mechanisms of subsequent equilibration.
Electromagnetic Radiation From An Equilibrium Quark -Gluon Plasma System
Singh, S S; Jha, Agam K.
2006-01-01
We study the electromagnetic radiation from a hot and slightly strong interacting fireball system of quark-gluon plasma using the Boltzmann distribution function for the incoming particles and Bose-Einstein distribution for gluon in first calculation of electromagnetic radiation and Fermi-Dirac distribution for quark, antiquark and Boltzmann distribution for gluon in our second calculation. The thermal photon emission rate is found that it is infrared divergent for massless quarks which are discussed by many authors and regulate this divergence using different cut-off in the qurak mass. However we remove this divergence using the same technique of Braaten and Pisarski in the thermal mass of the system by using our model calculation in the coupling parameter. Thus the production rate of the thermal photon is found to be smoothly worked by this cut-off technique of our model. The result is found to be matched with the most of the theoretical calculations and it is in the conformity with the experimental results...
Chemical Evolution of Strongly Interacting Quark-Gluon Plasma
Directory of Open Access Journals (Sweden)
Ying-Hua Pan
2014-01-01
Full Text Available At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c. However, the quark-gluon plasma (QGP system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations.
KdV solitons in a cold quark gluon plasma
Fogaça, D A; Filho, L G Ferreira
2011-01-01
The relativistic heavy ion program developed at RHIC and now at LHC motivated a deeper study of the properties of the quark gluon plasma (QGP) and, in particular, the study of perturbations in this kind of plasma. We are interested on the time evolution of perturbations in the baryon and energy densities. If a localized pulse in baryon density could propagate throughout the QGP for long distances preserving its shape and without loosing localization, this could have interesting consequences for relativistic heavy ion physics and for astrophysics. A mathematical way to proove that this can happen is to derive (under certain conditions) from the hydrodynamical equations of the QGP a Korteveg-de Vries (KdV) equation. The solution of this equation describes the propagation of a KdV soliton. The derivation of the KdV equation depends crucially on the equation of state (EOS) of the QGP. The use of the simple MIT bag model EOS does not lead to KdV solitons. Recently we have developed an EOS for the QGP which include...
Momentum broadening in unstable quark-gluon plasma
Carrington, M E; Schenke, B
2016-01-01
Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $\\hat q$ which determines the radiative energy loss of the test parton. We develop a formalism which gives $\\hat q$ as the solution of an initial value problem, and we focus on extremely oblate plasmas which are physically relevant for relativistic heavy ion collisions. The parameter $\\hat q$ is found to be strongly dependent on time. For short times it is of the order of the equilibrium value, but at later times $\\hat q$ grows exponentially due to the interaction of the test parton with unstable modes and becomes much bigger than the value in equilibri...
Creating the Primordial Quark-Gluon Plasma at the LHC
Harris, John W.
2013-04-01
Ultra-relativistic collisions of heavy ions at the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) create an extremely hot system at temperatures (T) expected only within the first microseconds after the Big Bang. At these temperatures (T ˜ 2 x 10^12 K), a few hundred thousand times hotter than the sun's core, the known ``elementary'' particles cannot exist and matter ``melts'' to form a ``soup'' of quarks and gluons, called the quark-gluon plasma (QGP). This ``soup'' flows easily, with extremely low viscosity, suggesting a nearly perfect hot liquid of quarks and gluons. Furthermore, the liquid is dense, highly interacting and opaque to energetic probes (fast quarks or gluons). RHIC has been in operation for twelve years and has established an impressive set of findings. Recent results from heavy ion collisions at the LHC extend the study of the QGP to higher temperatures and harder probes, such as jets (energetic clusters of particles), particles with extremely large transverse momenta and those containing heavy quarks. I will present a motivation for physics in the field and an overview of the new LHC heavy ion results in relation to results from RHIC.
Deconfinement phase transition in a finite volume in the presence of massive particles
Energy Technology Data Exchange (ETDEWEB)
Ait El Djoudi, A.; Ghenam, L. [Laboratoire de Physique des Particules et Physique Statistique, Ecole Normale Superieure - Kouba, B.P. 92, 16050, Vieux Kouba, Algiers (Algeria)
2012-06-27
We study the QCD deconfinement phase transition from a hadronic gas to a Quark-Gluon Plasma, in the presence of massive particles. Especially, the influence of some parameters as the finite volume, finite mass, flavors number N{sub f} on the transition point and on the order of the transition is investigated.
Quarkonium states in an anisotropic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Guo Yun
2009-09-10
In this work we study the properties of quarkonium states in a quark-gluon plasma which, due to expansion and non-zero viscosity, exhibits a local anisotropy in momentum space. We determine the hard-loop resummed gluon propagator in an anisotropic QCD plasma in general linear gauges and define a potential between heavy quarks from the Fourier transform of its static limit. This potential which arises due to one-gluon exchange describes the force between a quark and anti-quark at short distances. It is closer to the vacuum potential as compared to the isotropic Debye screened potential which indicates the reduced screening in an anisotropic QCD plasma. In addition, angular dependence appears in the potential; we find that there is stronger attraction on distance scales on the order of the inverse Debye mass for quark pairs aligned along the direction of anisotropy than for transverse alignment. The potential at long distances, however, is non-perturbative and modeled as a QCD string which is screened at the same scale as the Coulomb field. At asymptotic separation the potential energy is non-zero and inversely proportional to the temperature. With a phenomenological potential model which incorporates the different behaviors at short and long distances, we solve the three-dimensional Schroedinger equation. Our numerical results show that quarkonium binding is stronger at non-vanishing viscosity and expansion rate, and that the anisotropy leads to polarization of the P-wave states. Furthermore, we determine viscosity corrections to the imaginary part of the heavy-quark potential in the weak-coupling hard-loop approximation. The imaginary part is found to be smaller (in magnitude) than at vanishing viscosity. This implies a smaller decay width of quarkonium bound states in an anisotropic plasma. (orig.)
Real time observables for the quark-gluon plasma from the lattice
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Christian
2014-07-01
In this thesis we studied real time quantities and processes of the quark-gluon plasma. We employed the fundamental theory of QCD allowing for predictions from first principles. Treating QCD on the lattice enabled us to access non-perturbative regimes and for the very first time we computed a hydrodynamic transport coefficient without having to resort to maximum entropy methods or functional input. Furthermore we established a semi-classical formulation of QCD that we applied to investigate the effects of dynamic fermions as well as of using the correct colour group of QCD, SU(3), on the isotropization process of the quark-gluon plasma. In this work we have calculated the second order hydrodynamic transport coefficient κ for the Yang-Mills plasma using lattice perturbation theory and Monte Carlo simulations. From calculations both in strong and weak coupling limits, we expect a temperature dependence of κ∝T{sup 2}. In the investigated temperature range 2T{sub c}
Origin of Temperature of Quark-Gluon Plasma in Heavy Ion Collisions
Xu, Xiao-Ming
2015-01-01
Initially produced quark-gluon matter at RHIC and LHC does not have a temperature. A quark-gluon plasma has a high temperature. From this quark-gluon matter to the quark-gluon plasma is the early thermalization or the rapid creation of temperature. Elastic three-parton scattering plays a key role in the process. The temperature originates from the two-parton scattering, the three-parton scattering, the four-parton scattering and so forth in quark-gluon matter.
Heavy-quark transport coefficients in a hot viscous quark-gluon plasma medium
Das, Santosh K.; Chandra, Vinod; Alam, Jan-e.
2014-01-01
Heavy-quark (HQ) transport coefficients have been estimated for a viscous quark-gluon plasma (QGP) medium, utilizing a recently proposed quasi-particle description based on a realistic QGP equation of state (EoS). Interactions entering through the EoS significantly suppress the temperature dependence of the drag coefficient of QGP, compared to those of an ideal relativistic system of quarks and gluons. The inclusion of shear and bulk viscosities through the corrections to the thermal phase space factors of the bath particles alters the magnitude of the drag coefficient; the enhancement is significant at lower temperatures. In the competition between the effects of the EoS and dissipative corrections through phase space factors, the former eventually dictate how the drag coefficient would behave as a function of temperature and how much it quantitatively digresses from the ideal case. The observations suggest a significant impact of both the realistic EoS and the viscosities on the HQs transport at Relativistic Heavy Ion Collider and Large Hadron Collider collision energies.
Perfect Fluidity of the Quark Gluon Plasma Core as Seen through its Dissipative Hadronic Corona
Hirano, T; Hirano, Tetsufumi; Gyulassy, Miklos
2006-01-01
The agreement of hydrodynamic predictions of differential elliptic flow and radial flow patterns with Au+Au data is one of the main lines of evidence suggesting the nearly perfect fluid properties of the strongly coupled Quark Gluon Plasma, sQGP, produced at RHIC. We study the sensitivity of this conclusion to different hydrodynamic assumptions on chemical and thermal freezeout after the sQGP hadronizes. We show that if chemical freezeout occurs at the hadronization time, the differential elliptic flow for pions increase with proper time in the late hadronic phase until thermal freezeout and leads to a discrepancy with the data. In contrast, if both chemical and thermal equilibrium are maintained past the hadronization, then the mean pT per pion increases in a way that accidentally preserves v2(pT) from the sQGP phase in agreement with the data, but at the cost of the agreement with the hadronic yields. In order that all the data on hadronic ratios, radial flow, and differential elliptic flow be reproduced, t...
Long wavelength perfect fluidity from short distance jet transport in quark-gluon plasmas
Xu, Jiechen; Gyulassy, Miklos
2015-01-01
We build a new phenomenological framework that bridges the long wavelength bulk viscous transport properties of the strongly-coupled quark-gluon plasma (sQGP) and short distance hard jet transport properties in the QGP. The full nonperturbative chromo-electric (E) and chromo-magnetic (M) structure of the near "perfect fluid" like sQGP in the critical transition region are integrated into a semi-Quark-Gluon-Monopole Plasma (sQGMP) model lattice-compatibly and implemented into the new CUJET3.0 jet quenching framework. All observables computed from CUJET3.0 are found to be consistent with available data at RHIC and LHC simultaneously. A quantitative connection between the shear viscosity and jet transport parameter is rigorously established within this framework. We deduce the $T=160-600$ MeV dependence of the QGP's $\\eta/s$: its near vanishing value in the near $T_c$ regime is determined by the composition of E and M charges, it increases as $T$ rises, and its high $T$ limit is fixed by color screening scales.
Long wavelength perfect fluidity from short distance jet transport in quark-gluon plasmas
Xu, Jiechen; Liao, Jinfeng; Gyulassy, Miklos
2016-12-01
We build a new phenomenological framework that bridges the long wavelength bulk viscous transport properties of the strongly-coupled quark-gluon plasma (sQGP) and short distance hard jet transport properties in the QGP. The full nonperturbative chromo-electric (E) and chromo-magnetic (M) structure of the near "perfect fluid" like sQGP in the critical transition region are integrated into a semi-Quark-Gluon-Monopole Plasma (sQGMP) model lattice-compatibly and implemented into the new CUJET3.0 jet quenching framework. All observables computed from CUJET3.0 are found to be consistent with available data at RHIC and LHC simultaneously. A quantitative connection between the shear viscosity and jet transport parameter is rigorously established within this framework. We deduce the T = 160 - 600 MeV dependence of the QGP's η / s: its near vanishing value in the near Tc regime is determined by the composition of E and M charges, it increases as T rises, and its high T limit is fixed by color screening scales.
Perturbative and nonperturbative aspects of jet quenching in near-critical quark-gluon plasmas
Xu, Jiechen
In this thesis, we construct two QCD based energy loss models to perform quantitative analysis of jet quenching observables in ultra-relativistic nucleus-nucleus collisions at RHIC and the LHC. We first build up a perturbative QCD based CUJET2.0 jet flavor tomography model that couples the dynamical running coupling DGLV opacity series to bulk data constrained relativistic viscous hydrodynamic backgrounds. It solves the strong heavy quark energy loss puzzle at RHIC and explains the surprising transparency of the quark-gluon plasma (QGP) at the LHC. The observed azimuthal anisotropy of hard leading hadrons requires a path dependent jet-medium coupling in CUJET2.0 that implies physics of nonperturbative origin. To explore the nonperturbative chromo-electric and chromo-magnetic structure of the strongly-coupled QGP through jet probes, we build up a new CUJET3.0 framework that includes in CUJET2.0 both Polyakov loop suppressed semi-QGP chromo-electric charges and emergent chromo-magnetic monopoles in the critical transition regime. CUJET3.0 quantitatively describes the anisotropic hadron suppression at RHIC and the LHC. More significantly, it provides a robust connection between the long wavelength ``perfect fluidity'' of the QGP and the short distance jet transport in the QGP. This framework paves the way for ``measuring'' both perturbative and nonperturbative properties of the QGP, and more importantly for probing color confinement through jet quenching.
Evolution of Baryon Rich Quark-Gluon Plasma and radiation of Single Photons
Sastry, S; Mohanty, A K; Srivastava, D K
2002-01-01
The (3+1) dimensional expansion of the quark gluon plasma (QGP) produced at finite baryon density has been studied using relativistic hydrodynamical approach. The pressure functional of the equation of state (EoS) has been determined for the interacting nuclear matter with mesons exchange. The EoS has been used to solve hydrodynamical equations using RHLLE algorithm. The space time expansion of the plasma has been studied for the cases of SPS energy and RHIC energy both at finite baryon density and for a hypothetical case of SPS energy at zero baryon density. The space-time evolution is slowed and the life times of QGP and mixed phases are shortened in the presence of finite baryon density. The space time integrated total photon yields have been estimated by convoluting the static emission rates with the space time expansion of the plasma. It has been shown that the total photon yield at zero rapidity is not significantly affected by the baryon density for SPS energy. The total photon yield is unaffected by t...
Cosmological Consequences of QCD Phase Transition(s) in Early Universe
Tawfik, A
2008-01-01
We discuss the cosmological consequences of QCD phase transition(s) on the early universe. We argue that our recent knowledge about the transport properties of quark-gluon plasma (QGP) should throw additional lights on the actual time evolution of our universe. Understanding the nature of QCD phase transition(s), which can be studied in lattice gauge theory and verified in heavy ion experiments, provides an explanation for cosmological phenomenon stem from early universe.
Search and study of Quark Gluon Plasma at the CERN-LHC
Nayak, Tapan
2009-01-01
The major aim of nucleus-nucleus collisions at the LHC is to study the physics of strongly interacting matter and the quark gluon plasma (QGP), formed in extreme conditions of temperature and energy density. We give a brief overview of the experimental program and discuss the signatures and observables for a detailed study of QGP matter.
Introduction to the Quark-Gluon Plasma session in RJC 2014
Maire, Antonin
2015-01-01
This contribution is a brief introduction to the physics of Quark-Gluon Plasma (QGP); the intention is to set the stage for the corresponding session proceedings of the "Rencontre Jeunes Chercheurs 2014". The text consists in a description of the Bjorken scenario of a heavy-ion collision followed by the introduction of the notion of hard probe for QGP studies.
Energy Technology Data Exchange (ETDEWEB)
Redlich, K.
1985-04-01
Strangeness production in hot nuclear matter in the non-interacting gas approximation with an Usub(B)(1)xUsub(S)(1) internal symmetry group is discussed. It is argued that the stangeness abundancy ratio in the quark-gluon plasma as compared to the hadron gas strongly depends on under which thermodynamical circumstances it has been computed.
Equation of state of a quark-gluon plasma using the Cornell potential
Udayanandan, K. M.; Sethumadhavan, P.; Bannur, V. M.
2007-10-01
The equation of state (EOS) of quark-gluon plasma (QGP) using the Cornell potential based on Mayer's cluster expansion is presented. The string constant and the strong coupling constant for QGP are calculated. The EOS developed could describe the lattice EOS for pure gauge, two-flavor and three-flavor QGP qualitatively.
Photons from a Chemically Equilibrating Quark-Gluon Plasma at Finite Baryon Density
Institute of Scientific and Technical Information of China (English)
HE Ze-Jun; LONG Jia-Li; MA Yu-Gang; MA Guo-Liang
2005-01-01
@@ We study hard photon production in a chemically equilibrating quark-gluon plasma at finite baryon density based on the Jüttner distribution of partons of the system. We find that the photon yield is a strongly increasing function of the initial quark chemical potential.
Thermal rho`s in the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Pisarski, R.D.
1995-03-01
I discuss different models which predict changes in the mass of the thermal {rho} field. I emphasize that while the predictions are strongly model dependent, nevertheless substantial shifts in the thermal {rho} mass are expected to occur at the point of phase transition. As long as the thermal {rho} peak does not become too broad, this should provide a striking signature of the existence of a phase transition.
Thermal $\\varrho$s in the quark-gluon plasma
Pisarski, R D
1995-01-01
I discuss different models which predict changes in the mass of the thermal \\rho field. I emphasize that while the predictions are strongly model dependent, nevertheless substantial shifts in the thermal \\rho mass are expected to occur at the point of phase transition. As long as the thermal \\rho peak does not become too broad, this should provide a striking signature of the existence of a phase transition. (Based upon a talk presented at Quark Matter '95, Monterey, CA, Jan., 1995.)
Production and elliptic flow of dileptons and photons in a matrix model of the quark-gluon plasma.
Gale, Charles; Hidaka, Yoshimasa; Jeon, Sangyong; Lin, Shu; Paquet, Jean-François; Pisarski, Robert D; Satow, Daisuke; Skokov, Vladimir V; Vujanovic, Gojko
2015-02-20
We consider a nonperturbative approach to the thermal production of dileptons and photons at temperatures near the critical temperature in QCD. The suppression of colored excitations at low temperature is modeled by including a small value of the Polyakov loop, in a "semi"-quark-gluon plasma (QGP). Comparing the semi-QGP to the perturbative QGP, we find a mild enhancement of thermal dileptons. In contrast, to leading logarithmic order in weak coupling there are far fewer hard photons from the semi-QGP than the usual QGP. To illustrate the possible effects on photon and dilepton production in heavy-ion collisions, we integrate the rate with a simulation using ideal hydrodynamics. Dileptons uniformly exhibit a small flow, but the strong suppression of photons in the semi-QGP tends to weight the elliptical flow of photons to that generated in the hadronic phase.
Chen, Jiunn-Wei; Song, Yu-Kun; Wang, Qun
2012-01-01
We calculate the shear (eta) and bulk (zeta) viscosities of a weakly coupled quark gluon plasma at the leading-log order with finite temperature T and quark chemical potential mu. We find that the shear viscosity to entropy density ratio eta/s increases monotonically with mu and eventually scales as (mu/T)^2 at large mu. In contrary, zeta/s is insensitive to mu. Both eta/s and zeta/s are monotonically decreasing functions of the quark flavor number N_f when N_f \\geq 2. This property is also observed in pion gas systems. Our perturbative calculation suggests that QCD becomes the most perfect (i.e. with the smallest eta/s) at mu=0 and N_f = 16 (the maximum N_f with asymptotic freedom). It would be interesting to test whether the currently smallest eta/s computed close to the phase transition with mu=0 and N_f = 0 can be further reduced by increasing N_f.
Quark self-energy in an ellipsoidally anisotropic quark-gluon plasma
Kasmaei, Babak S; Strickland, Michael
2016-01-01
We calculate the quark self-energy in a quark-gluon plasma that possesses an ellipsoidal momentum-space anisotropy in the local rest frame. By introducing additional transverse momentum anisotropy parameters into the parton distribution functions, we generalize previous results which were obtained for the case of a spheroidal anisotropy. Our results demonstrate that the presence of anisotropies in the transverse directions affects the real and imaginary parts of quark self-energy and, consequently, the self-energy depends on both the polar and azimuthal angles in the local rest frame of the matter. Our results for the quark self-energy set the stage for the calculation of the effects of ellipsoidal momentum-space anisotropy on quark-gluon plasma photon spectra and collective flow.
Velocity statistics in holographic fluids: magnetized quark-gluon plasma and superfluid flow
Energy Technology Data Exchange (ETDEWEB)
Areán, Daniel [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805, Munich (Germany); Zayas, Leopoldo A. Pando [The Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34014 Trieste (Italy); Michigan Center for Theoretical Physics, Department of Physics, University of Michigan,450 Church Street, Ann Arbor, MI 48109 (United States); Patiño, Leonardo; Villasante, Mario [Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México,A.P. 70-542, México D.F. 04510 (Mexico)
2016-10-28
We study the velocity statistics distribution of an external heavy particle in holographic fluids. We argue that when the dual supergravity background has a finite temperature horizon the velocity statistics goes generically as 1/v, compatible with the jet-quenching intuition from the quark-gluon plasma. A careful analysis of the behavior of the classical string whose apparent world sheet horizon deviates from the background horizon reveals that other regimes are possible. We numerically discuss two cases: the magnetized quark-gluon plasma and a model of superfluid flow. We explore a range of parameters in these top-down supergravity solutions including, respectively, the magnetic field and the superfluid velocity. We determine that the velocity statistics goes largely as 1/v, however, as we leave the non-relativistic regime we observe some deviations.
Workshop on Quark-Gluon Plasma and Relativistic Heavy Ions
Lombardo, Maria Paola; Nardi, Marzia; GISELDA 2002; QGP 2002
2002-01-01
This book offers the unique possibility of tackling the problem of hadronic deconfinement from different perspectives. After general introductions to the physical issues, from both the theoretical and the experimental point of view, the book presents the most recent expertise on field theory approaches to the QCD phase diagram, many-body techniques and applications, the dynamics of phase transitions, and phenomenological analysis of relativistic heavy ion collisions. One of the major goals of this book is to promote interchange among those fields of research, which have traditionally been cult
Spectral functions in the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Asakawa, Masayuki [Kyoto Univ., Kyoto (Japan)
2002-09-01
Using the maximum entropy method, spectral functions of the vector mesons are extracted from lattice Monte Carlo data of the zero-temperature imaginary time Green's functions. The resonance and continuum structures as well as the ground state peaks are successfully obtained. In addition, we present a preliminary result for finite temperature spectral functions in the vector channel above the confinement-deconfinement phase transition temperature. (author)
Meiling, Yu; Lianshou, Liu
2008-01-01
Pair distribution function for delocalized quarks in the strongly coupled quark gluon plasma (sQGP) as well as in the states at intermediate stages of crossover from hadronic matter to sQGP are calculated using a molecule-like aggregation model. The shapes of the obtained pair distribution functions exhibit the character of liquid. The increasing correlation length in the process of crossover indicates a diminishing viscosity of the fluid system.
Finite Temperature Lattice QCD - Baryons in the Quark-Gluon Plasma
Aarts, Gert; De Boni, Davide; Hands, Simon; Jäger, Benjamin; Praki, Chrisanthi; Skullerud, Jon-Ivar
2016-01-01
Baryonic correlation functions provide an ideal tool to study parity doubling and chiral symmetry using lattice simulations. We present a study using $2+1$ flavors of anisotropic Wilson clover fermions on the FASTSUM ensembles and find clear evidence that parity doubling emerges in the quark-gluon plasma. This result is confirmed on the level of spectral functions, which are obtained using a MEM reconstruction. We further highlight the importance of Gaussian smearing in this study.
Non-perturbative effects for the Quark-Gluon Plasma equation of state
Energy Technology Data Exchange (ETDEWEB)
Begun, V. V., E-mail: viktor.begun@gmail.com; Gorenstein, M. I., E-mail: goren@bitp.kiev.ua; Mogilevsky, O. A. [Bogolyubov Institute for Theoretical Physics (Ukraine)
2012-07-15
The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.
Non-perturbative effects for the Quark-Gluon Plasma equation of state
Begun, V. V.; Gorenstein, M. I.; Mogilevsky, O. A.
2012-07-01
The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.
Equation of State of the Quark Gluon Plasma within the Quasi-particle Approach
Begun, Viktor V; Mogilevsky, Oleg A
2010-01-01
We propose simple analytical form of the quark-gluon plasma (QGP) equation of state (EoS) based on a quasi-particle approach. This new EoS satisfies all qualitative features observed in the lattice QCD calculations and gives a good quantitative description of the lattice results in SU(3) gluodynamics. The suggested EoS opens up new possibilities for hydrodynamic and kinetic phenomenological applications in the studies of the QGP.
Quark-gluon plasma freeze-out from a supercooled state?
Csörgö, T
1994-01-01
The quark-gluon plasma, formed in the first 3 fm/c of the heavy ion collisions at RHIC and LHC, supercooles due to nucleation and develops soon a negative pressure in the bag model. The negative pressure yields mechanical instability which may lead to a sudden timelike deflagration to a (super)heated hadron gas. The resulting freeze-out times are shorter than those of the standard nucleation scenario.
A mean field theory for the cold quark gluon plasma applied to stellar structure
Energy Technology Data Exchange (ETDEWEB)
Fogaca, D. A.; Navarra, F. S.; Franzon, B. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)
2013-03-25
An equation of state based on a mean-field approximation of QCD is used to describe the cold quark gluon plasma and also to study the structure of compact stars. We obtain stellar masses compatible with the pulsar PSR J1614-2230 that was determined to have a mass of (1.97 {+-} 0.04 M{sub Circled-Dot-Operator }), and the corresponding radius around 10-11 km.
Physics of hot hadronic matter and quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Shuryak, E.V.
1990-07-01
This Introductory talk contains a brief review of the current status of theoretical and experimental activities related to physics of superdense matter. In particular, we discuss latest lattice results on the phase transition, recent progress in chiral symmetry physics based on the theory of interacting instantons, new in the theory of QGP and of hot hadronic matter, mean p{sub t} and collective flow, the shape of p{sub t} distribution, strangeness production, J/{psi} suppression and {phi} enhancement, two puzzles connected with soft pion and soft photon enhancements, and some other ultrasoft'' phenomena. 56 refs., 6 figs.
SPECTRAL PROPERTIES OF QUARKS IN THE QUARK-GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
KARSCH,F.; KITAZAWA, M.
2007-07-30
We analyze the spectral properties of the quark propagator above the critical temperature for the deconfinement phase transition in quenched lattice QCD using clover improved Wilson fermions. The bare quark mass dependence of the quark spectral function is analyzed by varying the hopping parameter {kappa} in Landau gauge. We assume a two-pole structure for the quark spectral function, which is numerically found to work quite well for any value of {kappa}. It is shown that in the chiral limit the quark spectral function has two collective modes that correspond to the normal and plasmino excitations, while it is dominated by a single-pole structure when the bare quark mass becomes large.
Spectral Properties of Quarks in the Quark-Gluon Plasma
Karsch, F
2007-01-01
We analyze the spectral properties of the quark propagator above the critical temperature for the deconfinement phase transition in quenched lattice QCD using clover improved Wilson fermions. The bare quark mass dependence of the quark spectral function is analyzed by varying the hopping parameter \\kappa in Landau gauge. We assume a two-pole structure for the quark spectral function, which is numerically found to work quite well for any value of \\kappa. It is shown that in the chiral limit the quark spectral function has two collective modes that correspond to the normal and plasmino excitations, while it is dominated by a single-pole structure when the bare quark mass becomes large.
Properties of the Quark Gluon Plasma: A lattice perspective
Karsch, Frithjof
2007-01-01
We discuss results from lattice calculations for a few observables that are sensitive to different length scales in the high temperature phase of QCD and can give insight into its non-perturbative structure. We compare lattice results with perturbative calculations at high temperature obtained for vanishing and non-vanishing quark chemical potential.
Nucleation rate of the quark-gluon plasma droplet at ﬁnite quark chemical potential
Indian Academy of Sciences (India)
D S Gosain; S Somorendro Singh; Agam K Jha
2012-05-01
The nucleation rate of quark-gluon plasma (QGP) droplet is computed at ﬁnite quark chemical potential. In the course of computing the nucleation rate, the ﬁnite size effects of the QGP droplet are taken into account. We consider the phenomenological ﬂow parameter of quarks and gluons, which is dependent on quark chemical potential and we calculate the nucleation rate of the QGP droplet with this parameter. While calculating the nucleation rate, we ﬁnd that for low values of quark phenomenological parameter $ q$, nucleation rate is negligible and when increases, nucleation rate increases signiﬁcantly.
Astrophysical aspects of neutrino dynamics in ultra-degenerate quark gluon plasma
Adhya, Souvik Priyam
2016-01-01
The cardinal focus of the present review is to explore the role of neutrinos originating from the ultra-dense core of neutron stars composed of quark gluon plasma in the astrophysical scenario. The collective excitations of the quarks involving the neutrinos through the different kinematical processes have been studied. The cooling of the neutron stars as well as pulsar kicks due to asymmetric neutrino emission have been discussed in detail. Results involving calculation of relevant physical quantities like neutrino mean free path and emissivity have been presented in the framework of non-Fermi liquid behavior as applicable to ultra-degenerate plasma.
Estimation of electric conductivity of the quark gluon plasma via asymmetric heavy-ion collisions
Hirono, Yuji; Hirano, Tetsufumi
2012-01-01
We show that in asymmetric heavy-ion collisions, especially off-central Cu+Au collisions, a sizable strength of electric field directed from Au nucleus to Cu nucleus is generated in the overlapping region, because of the difference in the number of electric charges between the two nuclei. This electric field would induce an electric current in the matter created after the collision, which result in a dipole deformation of the charge distribution. The directed flow parameters $v_1^{\\pm}$ of charged particles turn out to be sensitive to the charge dipole and provide us with information about electric conductivity of the quark gluon plasma.
Shear viscosity $\\eta$ to electric conductivity $\\sigma_{el}$ ratio for the Quark-Gluon Plasma
Puglisi, A.; Plumari, S.; Greco, V.
2014-01-01
The transport coefficients of strongly interacting matter are currently subject of intense theoretical and phenomenological studies due to their relevance for the characterization of the quark-gluon plasma produced in ultra relativistic heavy-ion collisions (uRHIC). We discuss the connection between the shear viscosity to entropy density ratio, $\\eta/s$, and the electric conductivity, $\\sigma_{el}$. Once the relaxation time is tuned to have a minimum value of $\\eta/s=1/4\\pi$ near the critical...
Dilepton production rate in a hot and magnetized quark-gluon plasma
Sadooghi, N
2016-01-01
The differential multiplicity of dileptons in a hot and magnetized quark-gluon plasma, $\\Delta_{B}\\equiv dN_{B}/d^{4}xd^{4}q$, is derived from first principles. The constant magnetic field $B$ is assumed to be aligned in a fixed spatial direction. It is shown that the anisotropy induced by the $B$ field is mainly reflected in the general structure of photon spectral density function. This is related to the imaginary part of the vacuum polarization tensor, $\\mbox{Im}[\\Pi^{\\mu\
Scattering of Quark-Quasiparticles in the Quark-Gluon Plasma
Energy Technology Data Exchange (ETDEWEB)
Mannarelli, M. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Rapp, R. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States)
2006-08-07
Employing a Brueckner-type many-body approach, based on a driving potential extracted from lattice QCD, we study light quark properties in a Quark-Gluon Plasma (QGP) at moderate temperatures, T{approx}1-2T{sub c}. The quark-antiquark T-matrix is calculated self-consistently with pertinent quark self-energies. While the repulsive octet channel induces quasiparticle masses of up to 150 MeV, the attractive color-singlet part exhibits resonance structures which lead to quasiparticle widths of {approx}200MeV.
Yoctosecond metrology through Hanbury Brown-Twiss correlations from a quark-gluon plasma.
Ipp, Andreas; Somkuti, Peter
2012-11-09
Expansion dynamics at the yoctosecond time scale affect the evolution of the quark gluon plasma (QGP) created in heavy ion collisions. We show how these dynamics are accessible through Hanbury Brown-Twiss (HBT) intensity interferometry of direct photons emitted from the interior of the QGP. A detector placed close to the beam axis is particularly sensitive to early polar momentum anisotropies of the QGP. Observing a modification of the HBT signal at the proposed FoCal detector of the LHC ALICE experiment would allow us to measure the isotropization time of the plasma and could provide first experimental evidence for photon double pulses at the yoctosecond time scale.
What RHIC experiments and theory tell us about properties of quark-gluon plasma?
Shuryak, Edward
2005-03-01
This brief review summarizes the main experimental discoveries made at RHIC and then discusses their implications. The robust collective flow phenomena are well described by ideal hydrodynamics, with the equation of state (EoS) predicted by lattice simulations. However the transport properties turned out to be unexpected, with rescattering cross section one-to-two orders of magnitude larger than expected from perturbative QCD. These and other theoretical developments indicate that quark-gluon plasma (QGP) produced at RHIC, and probably in a wider temperature region TEoS, viscosity and jet quenching.
Jet flavor tomography of quark gluon plasmas at RHIC and LHC.
Buzzatti, Alessandro; Gyulassy, Miklos
2012-01-13
A new Monte Carlo model of jet quenching in nuclear collisions, CUJET1.0, is applied to predict the jet flavor dependence of the nuclear modification factor for fragments f=π,D,B,e(-) from quenched jet flavors g,u,c,b in central collisions at RHIC and LHC. The nuclear modification factors for different flavors are predicted to exhibit a novel level crossing pattern over a transverse momentum range 5
quark gluon plasmas.
Chemical Equilibration and Dilepton Production of Quark-Gluon Plasma at RHIC Energies
Institute of Scientific and Technical Information of China (English)
龙家丽; 贺泽君; 马国亮; 马余刚; 刘波
2004-01-01
An evolution model of the chemically equilibrating quark-gluon plasma system has been established based on the Jiittner distribution function of partons. By studying the dilepton production of the system, we find that due to high initial temperature, large gluon density of the system as well as large gluon fusion gg → c(c-) cross section in the intermediate mass region, a dominant contribution to dileptons with intermediate masses is provided by quark-antiquark annihilation qq → l(l-) and, especially, thermal charmed quarks from the gluon fusion gg → c(c-) and quark-antiquark annihilation qq → c(c-).
Heavy-Quark Diffusion Dynamics in Quark-Gluon Plasma under Strong Magnetic Fields
Hattori, Koichi; Yee, Ho-Ung; Yin, Yi
2016-01-01
We discuss heavy-quark dynamics in the quark-gluon plasma under a strong magnetic field induced by colliding nuclei. By the use of the diagrammatic resummation techniques for Hard Thermal Loop and the external magnetic field, we show analytic results of heavy-quark diffusion coefficient and drag force which become anisotropic due to the preferred spatial orientation in the magnetic field. We argue that the anisotropic diffusion coefficient gives rise to an enhancement/suppression of the heavy-quark elliptic flow depending on the transverse momentum.
The thermalization of soft modes in non-expanding isotropic quark gluon plasmas
Blaizot, Jean-Paul; Mehtar-Tani, Yacine
2016-01-01
We discuss the role of elastic and inelastic collisions and their interplay in the thermalization of the quark-gluon plasma. We consider a simplified situation of a static plasma, spatially uniform and isotropic in momentum space. We focus on the small momentum region, which equilibrates first, and on a short time scale. We obtain a simple kinetic equation that allows for an analytic description of the most important regimes. The present analysis suggests that the formation of a Bose condensate, expected when only elastic collisions are present, is strongly hindered by the inelastic, radiative, processes.
Dynamics of quark-gluon plasma produced in heavy ion collisions
Directory of Open Access Journals (Sweden)
Ruggieri M.
2014-01-01
Full Text Available In this talk, we report on our results about the computation of isotropization and thermalization times of the quark-gluon plasma produced in relativistic heavy ion collisions, as well as of the elliptic flow. Simulation of the evolving fireball is achieved by solving the relativistic Boltzmann equation for the parton distribution function tuned at a fixed shear viscosity to entropy density ratio η/s. Our results show that the saturation in the initial spectrum reduces the efficiency in building-up the elliptic flow. Moreover both thermalization and isotropization times are quite small, approximately of 1 fm/c, if the system is in a strong coupling regime.
Quark Gluon Plasma an Color Glass Condensate at RHIC? The perspective from the BRAHMS experiment
Arsene, I; Beavis, D; Besliu, C; Budick, B; Bøggild, H; Chasman, C; Christensen, C H; Christiansen, P; Cibor, J; Debbe, R; Enger, E; Gaardhøje, J J; Germinario, M; Hansen, O; Holm, A; Holme, A K; Hagel, K; Ito, H; Jakobsen, E; Jipa, A; Jundt, F; Jordre, J I; Jorgensen, C E; Karabowicz, R; Kim, E J; Kozik, T; Larsen, T M; Lee, J H; Lee, Y K; Lindahl, S; Løvhøiden, G; Majka, Z; Makeev, A; Mikelsen, M; Murray, M J; Natowitz, J B; Neumann, B; Nielsen, B S; Ouerdane, D; Planeta, R; Rami, F; Ristea, C; Ristea, O; Röhrich, D; Samset, B H; Sandberg, D; Sanders, S J; Scheetz, R A; Staszel, P; Tveter, T S; Videbaek, F; Wada, R; Yin, Z; Zgura, I S
2004-01-01
We review the main results obtained by the BRAHMS collaboration on the properties of hot and dense hadronic and partonic matter produced in ultrarelativistic heavy ion collisions at RHIC. A particular focus of this paper is to discuss to what extent the results collected so far by BRAHMS, and by the other three experiments at RHIC, can be taken as evidence for the formation of a state of deconfined partonic matter, the so called quark-gluon-plasma (QGP). We also discuss evidence for a possible precursor state to the QGP, i.e. the proposed Color Glass Condensate.
Flavour equilibration studies of quark-gluon plasma with non-zero baryon density
Indian Academy of Sciences (India)
Abhijit Sen
2009-12-01
Flavour equilibration for a thermally equilibrated but chemically non-equilibrated quark-gluon plasma is presented. Flavour equilibration is studied enforcing baryon number conservation. In addition to the usual processes like single additional gluon production $gg \\rightleftharpoons ggg$ and its reverse and quark–antiquark pair production by gluon pair fusion $gg \\rightleftharpoons q_{i}q_{i}^{-}$ and reverse thereof, processes like quark-flavour interchanging $q_{i}q_{i}^{-} \\rightleftharpoons q_{j}q_{j}^{-}$ is also considered. The degree of equilibration is studied comparatively for various reactions/constraints that are being considered.
On diquark clustering in quark-gluon plasma
Indian Academy of Sciences (India)
A K Sisodiya; V S Bhasin; R S Kaushal
2006-02-01
The possibility that pairs of quarks will form diquark clusters in the regime above deconfinement transition for hadron matter at finite density is revisited. Here we present the results on the diquark-diquark (dq-dq) interaction in the framework of constituent quark model taking account of spin, isospin and color degrees of freedom in the spirit of generalized Pauli principle. By constructing the appropriate spin and color states of the dq-dq clusters we compute the expectation values of the interaction Hamiltonian involving pairwise quark-quark interaction. We find that the effective interaction between two diquark clusters is quite sensitive to different configurations characterized by color and spin states, obtained after the coupling of two diquark states. The value of the coupling parameter for a particular color-spin state, i.e., $\\{\\bar{3}, 1\\}$ is compared to the one obtained earlier by Donoghue and Sateesh, Phys. Rev. D38, 360 (1988) based on the effective 4-theory. This new value of derived for different color-spin dq-dq states, may lead to several important implications in the studies of diquark star and diquark gas.
Surdutovich, Y
1998-01-01
We study the dynamics of quantum fluctuations which take place during the earliest stage of high-energy collision processes and the conditions under which the data from e– p deep- inelastic scattering(DIS) may serve as a guide for computing the initial data for heavy- ion collisions at high energies. Our method is essentially based on the space-time picture of these seemingly different phenomena. We analyze the inclusive quantum-mechanical measurements, in both cases, and derive the main results relying on causality. The main result is that the transition from the initial- state composite nuclei to the final-state dense system of quark-gluon fields, i.e. quark-gluon plasma, is possible only as a single quantum transition. We prove that the ultra-violet renormalization of virtual loops does not bring any scale into the problem. The scale appears only in connection with real processes of emission of quark and gluon fields and reveals itself through the collinear cut-off in the evolution equations. Thi...
Exciting gauge unstable modes of the quark-gluon plasma by relativistic jets
Energy Technology Data Exchange (ETDEWEB)
Mannarelli, M; Manuel, C [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autonoma de Barcelona, Facultat de Ciencies, Torre C5 E-08193 Bellaterra (Barcelona) (Spain)], E-mail: massimo@ieec.uab.es
2008-05-15
We present a study of the properties of the collective modes of a system composed by a thermalized quark-gluon plasma traversed by a relativistic jet of partons. We find that when the jet traverses the system unstable gauge field modes are excited and grow on very short time scales. The aim is to provide a novel mechanism for the description of the jet quenching phenomenon, where the jet crossing the plasma loses energy exciting colored unstable modes. In order to simplify the analysis we employ a linear response approximation, valid for short time scales. We assume that the partons in the jet can be described with a tsunami-like distribution function, whereas we treat the quark-gluon plasma employing two different approaches. In the first approach we adopt a Vlasov approximation for the kinetic equations, in the second approach we solve a set of fluid equations. In both cases we derive the expressions of the dispersion law of the collective unstable modes and compare the results obtained.
Effect of magnetic field on the photon radiation from quark-gluon plasma in heavy ion collisions
Zakharov, B G
2016-01-01
We develop a formalism for the photon emission from the quark-gluon plasma with an external electromagnetic field. We then use it to investigate the effect of magnetic field on the photon emission from the quark-gluon plasma created in $AA$ collisions. We find that even for very optimistic assumption on the magnitude of the magnetic field generated in $AA$ collisions its effect on the photon emission rate is practically negligible. For this reason the magnetic field cannot generate a significant azimuthal asymmetry in the photon spectrum.
Effect of the magnetic field on the photon radiation from quark-gluon plasma in heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Zakharov, B.G. [L.D. Landau Institute for Theoretical Physics, Moscow (Russian Federation)
2016-11-15
We develop a formalism for the photon emission from the quark-gluon plasma with an external electromagnetic field. We then use it to investigate the effect of the magnetic field on the photon emission from the quark-gluon plasma created in AA collisions. We find that even for a very optimistic assumption on the magnitude of the magnetic field generated in AA collisions its effect on the photon emission rate is practically negligible. For this reason the magnetic field cannot generate a significant azimuthal asymmetry in the photon spectrum. (orig.)
Fluctuations near the deconfinement phase transition boundary
Mishustin, I N
2005-01-01
In this talk I discuss how a first order phase transition may proceed in rapidly expanding partonic matter produced in a relativistic heavy-ion collision. The resulting picture is that a strong collective flow of matter will lead to the fragmentation of a metastable phase into droplets. If the transition from quark-gluon plasma to hadron gas is of the first order, it will manifest itself by strong nonstatistical fluctuations in observable hadron distributions. I discuss shortly existing experimental data on the multiplicity fluctuations.
Probing the Quark-Gluon Plasma from bottomonium production at forward rapidity with ALICE at the LHC
Marchisone, Massimiliano
The main goal of ultrarelativistic heavy-ion collisions is the study of the properties of the matter at very high temperatures and energy densities. Quantum chromodynamics (QCD) predicts in these conditions the existence of a new phase of the matter whose components are deconfined in a Quark-Gluon Plasma (QGP). Heavy quarks (charm e bottom) are produced in the first stages of the collisions, before to interact with the medium. Therefore, the measurement of the quarkonia (cc and bb mesons) is of particular interest for the study of the QGP: their dissociation mainly due to the colour screening is sensible to the initial temperature of the medium. Previous measurements at the SPS and RHIC allowed to understand some characteristics of the system produced, but they also opened many questions. With an energy 14 times higher than RHIC, the LHC (Large Hadron Collider) at CERN opened a new era for the study of the QGP properties. ALICE (A Large Ion Collider Experiment) is the LHC experiment fully dedicated to the stu...
Directory of Open Access Journals (Sweden)
Pari Sharareh Mehrabi
2016-01-01
Full Text Available The “Laplace Transform Method” is used to solve the Fokker-Plank equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.
Properties of Non-Conformal Quark Gluon Plasma of Holographic QCD Models from Compactified D4 Branes
Naji, J.
2016-08-01
In this article, we obtain some thermodynamics quantities of non-conformal gluonic matter. We extract specific heat, enthalpy and equation of state in terms of the temperature. Using transport properties we find important quantities of corresponding quark gluon plasma like drag force and jet-quenching.
Spinodal decomposition: An alternate mechanism of phase conversion
Indian Academy of Sciences (India)
P Shukla; A K Mohanty
2003-05-01
The scenario of homogeneous nucleation is investigated for a ﬁrst-order quark–hadron phase transition in a rapidly expanding background of quark gluon plasma. It is found that signiﬁcant supercooling is possible before hadronization begins. This study also suggests that spinodal decomposition competes with nucleation and may provide an alternative mechanism for phase conversion.
Equilibration Rates in a Strongly Coupled Nonconformal Quark-Gluon Plasma.
Buchel, Alex; Heller, Michal P; Myers, Robert C
2015-06-26
We initiate the study of equilibration rates of strongly coupled quark-gluon plasmas in the absence of conformal symmetry. We primarily consider a supersymmetric mass deformation within N=2^{*} gauge theory and use holography to compute quasinormal modes of a variety of scalar operators, as well as the energy-momentum tensor. In each case, the lowest quasinormal frequency, which provides an approximate upper bound on the thermalization time, is proportional to temperature, up to a prefactor with only a mild temperature dependence. We find similar behavior in other holographic plasmas, where the model contains an additional scale beyond the temperature. Hence, our study suggests that the thermalization time is generically set by the temperature, irrespective of any other scales, in strongly coupled gauge theories.
Jet-Medium Interactions at NLO in a Weakly-Coupled Quark-Gluon Plasma
Ghiglieri, Jacopo; Teaney, Derek
2015-01-01
We present an extension to next-to-leading order in the strong coupling constant $g$ of the AMY effective kinetic approach to the energy loss of high momentum particles in the quark-gluon plasma. At leading order, the transport of jet-like particles is determined by elastic scattering with the thermal constituents, and by inelastic collinear splittings induced by the medium. We reorganize this description into collinear splittings, high-momentum-transfer scatterings, drag and diffusion, and particle conversions (momentum-preserving identity-changing processes). We show that this reorganized description remains valid to NLO in $g$, and compute the appropriate modifications of the drag, diffusion, particle conversion, and inelastic splitting coefficients. In addition, a new kinematic regime opens at NLO for wider-angle collinear bremsstrahlung. These semi-collinear emissions smoothly interpolate between the leading order high-momentum-transfer scatterings and collinear splittings. To organize the calculation, w...
Thermalization of mini-jets in a quark-gluon plasma
Directory of Open Access Journals (Sweden)
Iancu Edmond
2016-01-01
Full Text Available We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.
On the Variational method for LPM Suppression of Photon Emission from Quark-Gluon Plasma
Sastry, S
2002-01-01
The photon emission rates from the quark gluon plasma have been studied considering LPM suppression effects. The integral equation for the transverse vector function (f(p)) that consists of multiple scattering effects has been solved using self-consistent iterations method. Empirical fits to the peak positions of the distributions from iteration method have been obtained for bremsstrahlung and annihilation with scattering (AWS) processes. The variational approach for f(p) calculation has been simplified considerably making some assumptions. Using this method, the photon emission rates at finite baryon density have been estimated. The LPM suppression factors for bremsstrahlung and annihilation with scattering (AWS) processes have been obtained as a function of photon energy and baryon density. The effect of baryon density has been shown to be rather weak and the suppression factors are similar to the zero density case. The suppression factors for AWS processes can be taken at zero density, whereas the bremsstr...
The quark gluon plasma equation of state and the expansion of the early Universe
Energy Technology Data Exchange (ETDEWEB)
Sanches, S.M.; Navarra, F.S.; Fogaça, D.A., E-mail: david@if.usp.br
2015-05-15
Our knowledge of the equation of state of the quark gluon plasma has been continuously growing due to the experimental results from heavy ion collisions, due to recent astrophysical measurements and also due to the advances in lattice QCD calculations. The new findings about this state may have consequences on the time evolution of the early Universe, which can be estimated by solving the Friedmann equations. The solutions of these equations give the time evolution of the energy density and also of the temperature in the beginning of the Universe. In this work we compute the time evolution of the QGP in the early Universe, comparing several equations of state, some of them based on the MIT bag model (and on its variants) and some of them based on lattice QCD calculations. Among other things, we investigate the effects of a finite baryon chemical potential in the evolution of the early Universe.
The Quark-Gluon Plasma Equation of State and the Generalized Uncertainty Principle
Directory of Open Access Journals (Sweden)
L. I. Abou-Salem
2015-01-01
Full Text Available The quark-gluon plasma (QGP equation of state within a minimal length scenario or Generalized Uncertainty Principle (GUP is studied. The Generalized Uncertainty Principle is implemented on deriving the thermodynamics of ideal QGP at a vanishing chemical potential. We find a significant effect for the GUP term. The main features of QCD lattice results were quantitatively achieved in case of nf=0, nf=2, and nf=2+1 flavors for the energy density, the pressure, and the interaction measure. The exciting point is the large value of bag pressure especially in case of nf=2+1 flavor which reflects the strong correlation between quarks in this bag which is already expected. One can notice that the asymptotic behavior which is characterized by Stephan-Boltzmann limit would be satisfied.
Nonperturbative heavy-quark diffusion in the quark-gluon plasma.
van Hees, H; Mannarelli, M; Greco, V; Rapp, R
2008-05-16
We evaluate heavy-quark (HQ) transport properties in a quark-gluon plasma (QGP) within a Brueckner many-body scheme employing interaction potentials extracted from thermal lattice QCD. The in-medium T matrices for elastic charm- and bottom-quark scattering off light quarks in the QGP are dominated by attractive meson and diquark channels which support resonance states up to temperatures of ~1.5T(c). The resulting drag coefficient increases with decreasing temperature, contrary to expectations based on perturbative QCD scattering. Employing relativistic Langevin simulations we compute HQ spectra and elliptic flow in sqrt[s(NN)]=200 GeV Au-Au collisions. A good agreement with electron decay data supports our nonperturbative computation of HQ diffusion, indicative for a strongly coupled QGP.
Jet-dilepton conversion from an anisotropic quark-gluon plasma
Mukherjee, Arghya; Roy, Pradip
2016-01-01
We calculate the yield of lepton pair production from jet-plasma interaction where the plasma is anisotropic in momentum space. We compare both the $M$ and $p_T$ distributions from such process with the Drell-Yan contribution. It is observed that the invariant mass distribution of lepton pair from such process dominate over the Drell-Yan up to $3$ GeV at RHIC and up to $10$ GeV at LHC. Moreover, it is found that the contribution from anistropic quark gluon plasma (AQGP) increases marginally compared to the isotropic QGP. In case of $p_T$-distribution we observe an increase by a factor of $3-4$ in the entire $p_T$-range at RHIC for AQGP. However, at LHC the change in the $p_T$-distribution is marginal as compared to the isotropic case.
Thermalization of mini-jets in a quark-gluon plasma
Iancu, Edmond; Wu, Bin
2016-12-01
We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP) by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.
Degrees of Freedom of the Quark Gluon Plasma, tested by Heavy Mesons
Berrehrah, H; Song, T; Ozvenchuck, V; Gossiaux, P B; Werner, K; Bratkovskaya, E; Aichelin, J
2016-01-01
Heavy quarks (charm and bottoms) are one of the few probes which are sensitive to the degrees of freedom of a Quark Gluon Plasma (QGP), which cannot be revealed by lattice gauge calculations in equilibrium. Due to the rapid expansion of the QGP energetic heavy quarks do not come to an equilibrium with the QGP. Their energy loss during the propagation through the QGP medium depends strongly on the modelling of the interaction of the heavy quarks with the QGP quarks and gluons, i.e. on the assuption of the degrees of freedom of the plasma. Here we compare the results of different models, the pQCD based Monte-Carlo (MC@sHQ), the Dynamical Quasi Particle Model (DQPM) and the effective mass approach, for the drag force in a thermalized QGP and discuss the sensitivity of heavy quark energy loss on the properties of the QGP as well as on non-equilibrium dynamics
Criterion for reducible hydrodynamic equations of baryon-rich quark-gluon plasma
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Besides the state equation there exists another cubic algebraic equation about μf in the form of μ3f + Pμf + q = 0, which relates parameters, temperature T, chemical potential μf, and net quark number nff (flavor f) for a baryon-rich quark-gluon plasma (QGP). A criterion may be acquired simply according to Cardan formula of the solution of the above equation, which gives naturally a condition: if n 《 27rT3/3/ , one may approximately use the conservation of specific entropy, and then the set of hydrodynamic equation of baryon-rich QGP may be reduced to the sct of hydrodynamic equation for baryon-free QGP.
Thermalization of the quark-gluon plasma and dynamical formation of Bose-Einstein Condensate
Liao, Jinfeng
2012-01-01
We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the pre-equilibrium gluonic matter (``glasma'') is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an {\\em emergent property} of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scattering. A possible transient Bose-Einstein Condensate is argued to form dynamically on a rather general ground. We develop the kinetic approach for describing this highly overpopulated system and find approximate scaling solutions as well as numerically study the onset of condensation. Finally we discuss possible phenomenological implications.
Collisional Energy Loss of a Heavy Quark in an Anisotropic Quark-Gluon Plasma
Romatschke, P; Romatschke, Paul; Strickland, Michael
2004-01-01
We compute the leading-order collisional energy loss of a heavy quark propagating through a quark-gluon plasma in which the quark and gluon distributions are anisotropic in momentum space. Following the calculation outlined for QED in an earlier work we indicate the differences encountered in QCD and their effect on the collisional energy loss results. For a 20 GeV bottom quark we show that momentum space anisotropies can result in the collisional heavy quark energy loss varying with the angle of propagation by up to 50%. For low velocity quarks we show that anisotropies result in energy gain instead of energy loss with the energy gain focused in such a way as to accelerate particles along the anisotropy direction thereby reducing the momentum-space anisotropy. The origin of this negative energy loss is explicitly identified as being related to the presence of plasma instabilities in the system.
Collective modes of an anisotropic quark-gluon plasma induced by relativistic jets
Mandal, Mahatsab
2012-01-01
We discuss the characteristics of collective modes induced by relativistic jets in an anisotropic quark-gluon plasma(AQGP). Assuming a tsunami-like initial jet distribution, it is found that the dispersion relations for both the stable and unstable modes are modified substantially due to the passage of jet compared to the case when there is no jet. It has also been shown that the growth rate of instability first increases compared to the no jet case and then completely turned into damping except the case when the jet velocity is perpendicular to the wave vector in which case the instability always grows. Thus, the introduction of the jet in the AQGP, in general, might to faster isotropization for the special case when the wave vector is parallel to the anisotropy axis.
Dijet induced collective modes in an anisotropic quark-gluon plasma
Mandal, Mahatsab
2012-01-01
We discuss the collective modes due to the propagation of two oppositely moving relativistic jets (dijet) in an anisotropic quark-gluon plasma(AQGP) and compare the results with the case of single jet propagation. Assuming a tsunami-like initial jet distribution, it is found that the dispersion relations for both the stable and unstable modes are altered significantly due to the passage of dijet compared to the case of single jet propagation. It has also been shown that the growth rate of instability, due to introduction of dijet in the system, increases compared to the case of single jet case. As in the case of single jet propagation, the instability always grows when the jet velocity is perpendicular to the wave vector. We, thus, argue that the introduction of dijet in the AQGP, in general, leads to faster isotropization (than single jet propagation) for the special case when the wave vector is parallel to the anisotropy axis.
Complex suppression patterns distinguish between major energy loss effects in Quark-Gluon Plasma
Djordjevic, Magdalena
2015-01-01
Interactions of high momentum partons with Quark-Gluon Plasma created in relativistic heavy-ion collisions provide an excellent tomography tool for this new form of matter. Recent measurements for charged hadrons and unidentified jets at the LHC show an unexpected flattening of the suppression curves at high momentum, exhibited when either momentum or the collision centrality is changed. Furthermore, a limited data available for B probes indicate a qualitatively different pattern, as nearly the same flattening is exhibited for the curves corresponding to two opposite momentum ranges. We here show that the experimentally measured suppression curves are well reproduced by our theoretical predictions, and that the complex suppression patterns are due to an interplay of collisional, radiative energy loss and the dead-cone effect. Furthermore, for B mesons, we predict that the uniform flattening of the suppression indicated by the limited dataset is in fact valid across the entire span of the momentum ranges, whic...
The sound produced by a fast parton in the quark-gluon plasma is a "crescendo"
Neufeld, R B
2009-01-01
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
The sound generated by a fast parton in the quark-gluon plasma is a crescendo
Neufeld, R B
2009-01-01
The total energy deposited into the medium per unit length by a fast parton traversing a quark-gluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.
Sound Produced by a Fast Parton in the Quark-Gluon Plasma is a ``Crescendo''
Neufeld, R. B.; Müller, B.
2009-07-01
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well-known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
Sound produced by a fast parton in the quark-gluon plasma is a "crescendo".
Neufeld, R B; Müller, B
2009-07-24
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well-known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
Turbulent chromo-fields and thermal particle production in quark-gluon plasma medium
Chandra, Vinod
2016-01-01
The Weibel type instabilities appear in the expanding quark-gluon plasma (QGP) in relativistic heavy-ion collisions, due to the presence of momentum-space anisotropy, are responsible for the generation of the turbulent color fields. The ensemble averaged (ensemble of the turbulent fields) effective diffusive Vlasov equation, for the modified momentum distribution functions of the quarks and gluons encodes the physics of such instability and leads to the anomalous transport process in the QGP medium. In the present case, the solution of the linearized transport equation for the modified momentum distribution functions has been served as the modeling for the non-equilibrium momentum distribution functions for the QGP degrees of freedom. The strength of anisotropy has been related to a phenomenologically obtained jet-quenching parameter, $\\hat{q}$. We have computed the contribution of these anisotropic terms to the thermal dilepton production rates. The production rate has been seen to be appreciably sensitive t...
Collective phenomena in the non-equilibrium quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Schenke, Bjoern Peter
2008-07-03
In this work we study the non-equilibrium dynamics of a quark-gluon plasma, as created in heavy-ion collisions. We investigate how big of a role plasma instabilities can play in the isotropization and equilibration of a quark-gluon plasma. In particular, we determine, among other things, how much collisions between the particles can reduce the growth rate of unstable modes. This is done both in a model calculation using the hard-loop approximation, as well as in a real-time lattice simulation combining both classical Yang-Mills-fields as well as inter-particle collisions. The new extended version of the simulation is also used to investigate jet transport in isotropic media, leading to a cutoff-independent result for the transport coefficient q. The precise determination of such transport coefficients is essential, since they can provide important information about the medium created in heavy ion collisions. In anisotropic media, the effect of instabilities on jet transport is studied, leading to a possible explanation for the experimental observation that high-energy jets traversing the plasma perpendicular to the beam axis experience much stronger broadening in rapidity than in azimuth. The investigation of collective modes in the hard-loop limit is extended to fermionic modes, which are shown to be all stable. Finally, we study the possibility of using high energy photon production as a tool to experimentally determine the anisotropy of the created system. Knowledge of the degree of local momentum-space anisotropy reached in a heavy-ion collision is essential for the study of instabilities and their role for isotropization and thermalization, because their growth rate depends strongly on the anisotropy. (orig.)
Hadronic multiplicity distribution and dynamical fluctuations under QGP phase transitions
Institute of Scientific and Technical Information of China (English)
杨纯斌; 鄢文标; 蔡勖
1999-01-01
Hadronic multiplicity distributions in small bins are studied within the Ginzburg-Landau description for quark-hadron phase transitions. Direct comparison of the distributions with Poisson ones （with the same averages） is made in the light of dynamical factors dq for the distributions and ratios Dq≡dq/d1. Scaling behavior between Dq’ s is found, which can be used to detect the formation of quark-gluon plasma. The same method can be used in the analysis of other processes without phase transition.
Institute of Scientific and Technical Information of China (English)
LONG Jia-Li; HE Ze-Jun; MA Yu-Gang
2006-01-01
@@ We investigate hard photon production of the near-collinear bremsstrahlung and a new process called the inelastic pair annihilation, fully including the LPM effect, in a chemically equilibrating quark-gluon plasma at finite baryon density, and find that the effect of the system evolution on the photon production and large contribution of the bremsstrahlung make the total photon yield of the two processes as a strongly increasing function of the initial quark chemical potential.
Recent Results on Soft Probes of the Quark-Gluon Plasma from the ATLAS Experiment at the LHC
Przybycien, M; The ATLAS collaboration
2014-01-01
Measurements of low-pT (< 5 GeV) particle production have provided valuable insight on the production and evolution of the quark-gluon plasma in Pb+Pb collisions at the LHC. In particular, measurements of elliptic and higher order collective flow imprinted on the azimuthal angle distributions of low-pT particles directly probe the strongly-coupled dynamics of the quark-gluon plasma and test hydrodynamic model descriptions of its evolution. The large acceptance of detectors like ATLAS has made it possible to measure flow event-by-event and to determine the correlations between different harmonics. Recent measurements of low-pT particle production and multi-particle correlations in proton-lead collisions have shown features similar to the collective flow observed in Pb+Pb collisions. Results will be presented from a variety of single and multi-particle measurements in Pb+Pb and proton-Pb collisions that probe the collective dynamics of the quark-gluon plasma and possibly provide evidence for collectivity in ...
Soft Probes of the Quark-Gluon Plasma with ALICE at LHC
Vernet, Renaud
2009-01-01
The Large Hadron Collider (LHC) should start its activity of data taking by the end of summer 2009, and will provide beams of p-p and Pb-Pb at colliding energies up to 14 TeV and 5.5 ATeV respectively. The Pb-Pb heavy-ion program aims at reaching the necessary conditions to create a deconfined state of partons, the Quark-Gluon Plasma (QGP), whose study is one of the most exciting physics topics to be explored thanks to the possibilites offered by this new-generation accelerator. In particular, the "soft" observables related to low and intermediate pT processes, will shed light on many fundamental properties of the system, such as thermodynamic parameters, chemical composition, expansion velocity etc. The p-p collisions will be of great interest as well, since they will serve as an essential reference for heavy ions. ALICE (A Large Ion Collider Experiment) is the LHC experiment dedicated to the study of the QGP. Its large acceptance and low magnetic field make it particularly suited for the study of soft pheno...
Are direct photons a clean signal of a thermalized quark gluon plasma?
Boyanovsky, D
2003-01-01
Direct photon production from a quark gluon plasma (QGP) in thermal equilibrium is studied directly in real time. In contrast to the usual S-matrix calculations, the real time approach is valid for a QGP that formed and reached LTE a short time after a collision and of finite lifetime ($\\sim 10-20 \\mathrm{fm}/c$ as expected at RHIC or LHC). We point out that during such finite QGP lifetime the spectrum of emitted photons carries information on the initial state. There is an inherent ambiguity in separating the virtual from the observable photons during the transient evolution of the QGP. We propose a real time formulation to extract the photon yield which includes the initial stage of formation of the QGP parametrized by an effective time scale of formation $\\Gamma^{-1}$. This formulation coincides with the S-matrix approach in the infinite lifetime limit. It allows to separate the virtual cloud as well as the observable photons emitted during the pre- equilibrium stage from the yield during the QGP lifetime....
Hadron production in relativistic heavy ion interactions and the search for the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Tannenbaum, M.J.
1989-12-01
The course starts with an introduction, from the experimentalist's point of view, of the challenge of measuring Relativistic Heavy Ion interactions. A review of some theoretical predictions for the expected signatures of the quark gluon plasma will be made, with a purpose to understand how they relate to quantities which may be experimentally measured. A short exposition of experimental techniques and details is given including charged particles in matter, momentum resolution, kinematics and Lorentz Transformations, calorimetry. Principles of particle identification including magnetic spectrometers, time of flight measurement. Illustrations using the E802 spectrometer and other measured results. Resolution smearing of spectra, and binning effects. Parent to daughter effects in decay, with {pi}{sup 0} {yields} {gamma} {gamma} as an example. The experimental situation from the known data in p -- p collisions and proton-nucleus reactions is reviewed and used as a basis for further discussions. The Cronin Effect'' and the Seagull Effect'' being two arcana worth noting. Then, selected experiments from the BNL and CERN heavy ion programs are discussed in detail. 118 refs., 45 figs.
Empirical Emission Functions for LPM Suppression of Photon Emission from Quark-Gluon Plasma
Sastry, S
2003-01-01
The LPM suppression of photon emission rates from the quark gluon plasma have been studied at different physical conditions of the plasma given by temperature and chemical potentials.The integral equation for the transverse vector function (f(p_t)) consisting of multiple scattering effects is solved for the parameter set {p,k,kappa,T}, for bremsstrahlung and AWS processes. The peak positions of these distributions depend only on the dynamical variable x=(T/kappa)|1/p-1/(p+k)|. Integration over these distributions multiplied by x^2 factor also depends on this variable x,leading to a unique global emission function g(x) for all parameters. Empirical fits to this dimensionless emission function, g(x), are obtained. The photon emission rate calculations with LPM suppression effects reduce to one dimensional integrals involving folding over the empirical g(x) function with appropriate distribution functions and the kinematic factors. Using this approach, the suppression factors for both bremsstrahlung and AWS have...
Quark-gluon plasma effects on hadrons in AdS/QCD
Bartz, Sean; Jacobson, Theodore
2016-09-01
The AdS/CFT correspondence has succeeded in describing qualitatively many features of non-perturbative QCD. An approach known as bottom-up AdS/QCD uses a dilaton field to break conformal symmetry, introducing confinement and describing well the features of hadronic spectra at zero temperature. Introducing a black hole into the AdS metric allows for the study of thermodynamic properties of QCD, mimicking the behavior of hadrons interacting with a hot, dense medium such as the quark-gluon plasma produced in heavy ion collisions. We present an improved AdS/QCD model for meson and glueball spectra at finite temperature and baryon chemical potential. The spectra match the experimental and lattice data qualitatively well at low temperature, but we also find some subtleties in connecting to the best zero-temperature models. We find a melting temperature for light mesons that is below the current estimates for the deconfinement temperature. Finally, we examine the melting and jet-quenching of heavy quarkonia, which more commonly act as probes of the QGP in heavy ion collisions.
Monte Carlo study of Quark Gluon Plasma using photon jet observables
Xing, Tian
2016-09-01
Relativistic heavy ion collisions create an exotic state of deconfined, nuclear matter called quark gluon plasma (QGP), providing an opportunity to study the strong interaction. In some particularly hard scattered events, a parton with high transverse momentum (pT) interacts with this medium before fragmenting into a spray of particles, called a jet. Jet properties of heavy ion collisions can be modified relative to expectations from pp collisions; this effect is called jet quenching. Measurement of the jet internal structure can provide information about this effect and about the medium itself. On the other hand, studying systems whose jets are recoiled against photons coming from an initial scattering offers a way to calibrate the momentum of the modified jet. Since photons do not carry color charge, they escape the QGP with their initial momentum intact. On this poster, results using the Monte Carlo event generators Pythia and JEWEL will be presented for fragmentation functions and jet suppression from photon-jet events, alongside experimental data from CMS and ATLAS at a center of mass energy of 2.76 TeV. Predictions are also presented for lead-lead collisions at a center of mass energy of 5.02 TeV.
Probing Quark-Gluon-Plasma properties with a Bayesian model-to-data comparison
Cai, Tianji; Bernhard, Jonah; Ke, Weiyao; Bass, Steffen; Duke QCD Group Team
2016-09-01
Experiments at RHIC and LHC study a special state of matter called the Quark Gluon Plasma (QGP), where quarks and gluons roam freely, by colliding relativistic heavy-ions. Given the transitory nature of the QGP, its properties can only be explored by comparing computational models of its formation and evolution to experimental data. The models fall, roughly speaking, under two categories-those solely using relativistic viscous hydrodynamics (pure hydro model) and those that in addition couple to a microscopic Boltzmann transport for the later evolution of the hadronic decay products (hybrid model). Each of these models has multiple parameters that encode the physical properties we want to probe and that need to be calibrated to experimental data, a task which is computationally expensive, but necessary for the knowledge extraction and determination of the models' quality. Our group has developed an analysis technique based on Bayesian Statistics to perform the model calibration and to extract probability distributions for each model parameter. Following the previous work that applies the technique to the hybrid model, we now perform a similar analysis on a pure-hydro model and display the posterior distributions for the same set of model parameters. We also develop a set of criteria to assess the quality of the two models with respect to their ability to describe current experimental data. Funded by Duke University Goldman Sachs Research Fellowship.
What RHIC Experiments and Theory tell us about Properties of Quark-Gluon Plasma ?
Shuryak, E V
2004-01-01
This brief review summarizes the main experimental discoveries made at RHIC and then discusses their implications. The robust collective flow phenomena are well described by ideal hydrodynamics, with the Equation of State (EoS) predicted by lattice simulations. However the transport properties turned out to be unexpected, with rescattering cross section one-to-two orders of magnitude larger than expected from perturbative QCD. These and other theoretical developments indicate that Quark-Gluon Plasma (QGP) produced at RHIC, and probably in a wider temperature region $T_c
Korteveg-de Vries solitons in a cold quark-gluon plasma
Fogaça, D. A.; Navarra, F. S.; Ferreira Filho, L. G.
2011-09-01
The relativistic heavy ion program developed at RHIC and now at LHC motivated a deeper study of the properties of the quark-gluon plasma (QGP) and, in particular, the study of perturbations in this kind of plasma. We are interested on the time evolution of perturbations in the baryon and energy densities. If a localized pulse in baryon density could propagate throughout the QGP for long distances preserving its shape and without loosing localization, this could have interesting consequences for relativistic heavy ion physics and for astrophysics. A mathematical way to prove that this can happen is to derive (under certain conditions) from the hydrodynamical equations of the QGP a Korteveg-de Vries (KdV) equation. The solution of this equation describes the propagation of a KdV soliton. The derivation of the KdV equation depends crucially on the equation of state (EOS) of the QGP. The use of the simple MIT bag model EOS does not lead to KdV solitons. Recently we have developed an EOS for the QGP which includes both perturbative and nonperturbative corrections to the MIT one and is still simple enough to allow for analytical manipulations. With this EOS we were able to derive a KdV equation for the cold QGP.
Spinodal Instabilities of Baryon-Rich Quark-gluon Plasma in the PNJL Model
Li, Feng
2016-01-01
Using the Polyakov-Nambu-Jona-Lasinia (PNJL) model, we study the spinodal instability of a baryon-rich quark-gluon plasma in the linear response theory. We find that the spinodal unstable region in the temperature and density plane shrinks with increasing wave number of the unstable mode and is also reduced if the effect of Polyakov loop is not included. In the small wave number or long wavelength limit, the spinodal boundaries in both cases of with and without the Polyakov loop coincide with those determined from the isothermal spinodal instability in the thermodynamic approach. Also, the vector interactions among quarks is found to suppress unstable modes of all wave numbers. Moreover, the growth rate of unstable modes initially increases with the wave number but is reduced when the wave number becomes large. Including the collisional effect from quark scattering via the linearized Boltzmann equation, we further find that it decreases the growth rate of unstable modes of all wave numbers. Relevance of these...
Resummation of Jet Shapes and Extracting Properties of the Quark-Gluon Plasma
Chien, Yang-Ting
2014-01-01
Understanding the properties of the quark-gluon plasma (QGP) that is produced in ultra-relativistic nucleus-nucleus collisions has been one of the top priorities of the heavy ion program at the LHC. Energetic jets are produced and subsequently quenched in the collisions. Such jet quenching phenomena provide promising tools to probe the medium properties by studying the modification of jets due to the medium interactions. Significant modifications of jet shapes have been measured. In this talk we focus on the calculation of jet shapes in both proton-proton and lead-lead collisions using soft-collinear effective theory (SCET), with Glauber gluon interactions in the medium. Large logarithms in jet shapes are resummed at next-to-leading logarithmic (NLL) accuracy by the renormalization-group evolution between hierarchical jet scales. The medium interactions contribute as power corrections, and we calculate the modification of jet shapes at leading order in opacity with the static QGP model. Preliminary results ar...
Complex suppression patterns distinguish between major energy loss effects in Quark-Gluon Plasma
Djordjevic, Magdalena
2016-12-01
Interactions of high momentum partons with Quark-Gluon Plasma created in relativistic heavy-ion collisions provide an excellent tomography tool for this new form of matter. Recent measurements for charged hadrons and unidentified jets at the LHC show an unexpected flattening of the suppression curves at high momentum, exhibited when either momentum or the collision centrality is changed. Furthermore, a limited data available for B probes indicate a qualitatively different pattern, as nearly the same flattening is exhibited for the curves corresponding to two opposite momentum ranges. We here show that the experimentally measured suppression curves are well reproduced by our theoretical predictions, and that the complex suppression patterns are due to an interplay of collisional, radiative energy loss and the dead-cone effect. Furthermore, for B mesons, we predict that the uniform flattening of the suppression indicated by the limited dataset is in fact valid across the entire span of the momentum ranges, which will be tested by the upcoming experiments. Overall, the study presented here, provides a rare opportunity for pQCD theory to qualitatively distinguish between the major energy loss mechanisms at the same (nonintuitive) dataset.
Electrical Conductivity of Quark-Gluon Plasma in Strong Magnetic Fields
Hattori, Koichi
2016-01-01
We compute the electrical conductivity of quark-gluon plasma in a strong magnetic field $B$ with quantum field theory at finite temperature using the lowest Landau level approximation. We provide the one-loop result arising from 1-to-2 scattering processes whose kinematics are satisfied by the (1+1) dimensional fermion dispersion relation. Due to the chirality conservation, the conductivity diverges in the massless limit, and is sensitive to the value of the current quark mass. As a result, we find that the conductivity along the direction of the magnetic field is quite large compared with the value at $B=0$, mainly because of the small value of the current quark mass. We show that the resummation of the ladder diagrams for the current-current correlator gives rise to only sub-leading contributions beyond the leading-log order, and thus verify our one-loop result at the leading-log accuracy. We also discuss possible implications for the relativistic heavy-ion collisions.
Dilepton production by dynamical quasiparticles in the strongly interacting quark gluon plasma
Linnyk, O
2010-01-01
The dilepton production by the constituents of the strongly interacting quark-gluon-plasma (sQGP) is addressed. In order to make quantitative predictions at realistically low plasma temperatures (O(T_c)), experimentally relevant low dilepton mass (O(1 GeV)) and strong coupling (alphaS=0.5-1), we take into account not only the higher order pQCD reaction mechanisms, but also the non-perturbative spectral functions (off-shellness) and self-energies of the quarks, anti-quarks and gluons thus going beyond the leading twist. For this purpose, our calculations utilize parametrizations of the non-perturbative propagators for quarks and gluons provided by the dynamical quasi-particle model (DQPM) matched to reproduce lattice data. The DQPM describes QCD properties in terms of single-particle Green's functions (in the sense of a two-particle irreducible approach) and leads to the notion of the constituents of the sQGP being effective quasiparticles, which are massive and have broad spectral functions (due to large inte...
Probing the Quark Gluon Plasma with Heavy Flavours: recent results from ALICE
CERN. Geneva
2017-01-01
The study of open heavy-flavour physics allows us to investigate the key properties of the Quark-Gluon Plasma (QGP) and the microscopic processes ongoing in the medium produced in heavy-ion collisions at relativistic energies. Heavy quarks are produced in the early stages of heavy-ion collisions and their further production and annihilation rates in the medium are expected to be very small throughout the evolution of the system. Therefore, they serve as penetrating probes that traverse the hot and dense medium, interact with the partonic constituents of the plasma and lose energy. Understanding the interactions of heavy quarks with the medium requires precise measurements over a wide momentum range in heavy-ion collisions, but also in smaller systems like pp collisions, which also test next-to-leading order perturbative QCD calculations, and proton-nucleus collisions, which are sensitive to Cold Nuclear Matter effects (CNM), such as the modification of the parton distribution functions of nuclei, and parton ...
On The Existence of a Holographic Description of the LHC Quark-Gluon Plasmas
McInnes, Brett
2016-01-01
Peripheral collisions of heavy ions can give rise to extremely intense magnetic fields. It has been suggested that these fields might invalidate the holographic description of the corresponding quark-gluon plasmas, assuming that these can be modelled by strongly coupled field theories. In the case of the plasmas produced in collisions at the RHIC facility (including in the beam energy scans), it is known how to deal with this problem: one has to take into account the large angular momenta generated in these plasmas, and the effects of the baryonic chemical potential. But this does not work for the plasmas produced in peripheral collisions at the LHC. However, these results neglect some (less significant) aspects of bulk physics; could it be that the problem is resolved by taking into account these lower-order effects? Here we use a bulk dilatonic field (fully compatible with boundary data, as well as with the asymptotically AdS character of the bulk geometry) as a model of these effects, and show that this is...
Quark production, Bose-Einstein condensates and thermalization of the quark-gluon plasma
Blaizot, Jean-Paul; Yan, Li
2014-01-01
In this paper, we study the thermalization of gluons and N_f flavors of massless quarks and antiquarks in a spatially homogeneous system. First, two coupled transport equations for gluons and quarks (and antiquarks) are derived within the diffusion approximation of the Boltzmann equation, with only 2 2 processes included in the collision term. Then, these transport equations are solved numerically in order to study the thermalization of the quark-gluon plasma. At initial time, we assume that no quarks or antiquarks are present and we choose the gluon distribution in the form f = f_0 theta (1-p/Q_s) with Q_s the saturation momentum and f_0 a constant. The subsequent evolution of systems may, or may not, lead to the formation of a (transient) Bose condensate, depending on the value of f_0. In fact, we observe, depending on the value of f_0, three different patterns: (a) thermalization without gluon Bose-Einstein condensate (BEC) for f_0 1 > f_{0c}, the onset of BEC occurs at a finite time t_c ~ 1/((alpha_s f_0...
Applied string theory, hot and cold. A holographic view on quark-gluon plasma and superfluids
Energy Technology Data Exchange (ETDEWEB)
Samberg, Andreas Wilhelm
2015-12-21
This thesis deals with applications of gauge/gravity duality to strong-coupling phenomena in the quark-gluon plasma and far-from-equilibrium superfluids. In a first part we search for model-independent (universal) behavior in various non-Abelian gauge-theory plasmas at finite temperature and chemical potential. We employ the holographic duals of strongly coupled N=4 supersymmetric Yang-Mills theory and three one-parameter families of non-conformal deformations thereof, two of which solve the equations of motion of a five-dimensional Einstein-Maxwell-scalar action. We study the free energy and associated thermodynamic quantities of heavy quarks and bound quark-anti-quark (Q anti Q) pairs as well as the Q anti Q binding energy and the running coupling. We find qualitative agreement with available lattice QCD data. Moreover, we show that several observables exhibit universal behavior for all values of the chemical potential. In a second part we investigate the real-time dynamics of a bosonic superfluid in two spatial dimensions after initial quenches that take the system to far-from-equilibrium states characterized by many topological vortex defects in association with quantum turbulence. To this end we numerically solve the full equations of motion of the holographically dual Abelian Higgs model on four-dimensional anti-de Sitter space. We observe a universal non-equilibrium late-time regime characterized by power-law behavior in a two-point correlation function and in characteristic length scales, which we interpret as a non-thermal fixed point.
Relating q ̂, η /s , and Δ E in an expanding quark-gluon plasma
Ayala, Alejandro; Dominguez, Isabel; Jalilian-Marian, Jamal; Tejeda-Yeomans, Maria Elena
2016-08-01
We use linear viscous hydrodynamics to describe the energy and momentum deposited by a fast moving parton in a quark gluon plasma. This energy-momentum is in turn used to compute the probability density for the production of soft partons by means of the Cooper-Frye formula. We use this probability density to render manifest a relation between the average transverse momentum given to the fast moving parton from the medium q ̂, the shear viscosity to entropy density ratio η /s , and the energy lost by the fast moving parton Δ E in an expanding medium under similar conditions to those generated in nucleus-nucleus collisions at the CERN Large Hadron Collider. We find that q ̂ increases linearly with Δ E for both trigger and away side partons that have been produced throughout the medium. On the other hand, η /s is more stable with Δ E . We also study how these transport coefficients vary with the geometrical location of the hard scattering that produces the fast moving partons. The behavior of q ̂, with Δ E , is understood as arising from the length of medium the parton traverses from the point where it is produced. However, since η /s is proportional to the ratio of the length of medium traversed by the fast parton and the average number of scatterings it experiences, it has a milder dependence on the energy it loses. This study represents a tool to obtain a direct connection between transport coefficients and the description of in-medium energy loss within a linear viscous hydrodynamical evolution of the bulk.
Energy Technology Data Exchange (ETDEWEB)
Ghenam, L.; Djoudi, A. Ait El [Laboratoire de Physique des Particules et Physique Statistique, Ecole Normale Superieure - Kouba, B.P. 92, 16050, Vieux Kouba, Algiers (Algeria)
2012-06-27
We study the finite size and finite mass effects for the thermal deconfinement phase transition in Quantum Chromodynamics (QCD), using a simple model of coexistence of hadronic (H) gas and quark-gluon plasma (QGP) phases in a finite volume. We consider the equations of state of the two phases with the QGP containing two massless u and d quarks and massive s quarks, and a hadronic gas of massive pions, and we probe the system near the transition. For this, we examine the behavior of the most important hydrodynamical quantities describing the system, at a vanishing chemical potential ({mu}= 0), with temperature and energy density.
Kumar, Yogesh; Singh, S. Somorendro
2016-07-01
We extend the previous study of dilepton production using [S. Somorendro Singh and Y. Kumar, Can. J. Phys. 92 (2014) 31] based on a simple quasiparticle model of quark-gluon plasma (QGP). In this model, finite value of quark mass uses temperature dependent chemical potential the so-called Temperature Dependent Chemical Potential Quark Mass (TDCPQM). We calculate dilepton production in the relevant range of mass region. It is observed that the production rate is marginally enhanced from the earlier work. This is due to the effect of TDCPQM and its effect is highly significant in the production of dilepton.
Jiang, Bing-feng; Hou, De-fu; Li, Jia-rong
2016-10-01
We derive the electric permittivity ɛ and magnetic permeability μM of the quark-gluon plasma (QGP) with the kinetic theory associated with a Bhatnagar-Gross-Krook (BGK) collisional kernel. Based on them, we study the effect of collisions on the refractive index of QGP. Compared to the collisionless case, collisions change the ω -behavior of ɛ and μM dramatically, which is responsible for the fact that the real and imaginary parts of n2 and the Depine-Lakhtakia index nDL are smooth functions of ω . For a small collision rate ν , the Depine-Lakhtakia index nDL is negative in some frequency range. When the collision rate increases, the frequency range for nDLindex nDL is positive for all frequency regions, which indicates a normal refractive index. In contrast to the collisionless case, there exists some frequency range in which nDLnegative refractive index.
Energy Technology Data Exchange (ETDEWEB)
Filinov, V.S.; Fortov, V.E. [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13, bd. 2, 125412 Moscow (Russian Federation); Bonitz, M. [Institute for Theoretical Physics and Astrophysics, Christian Albrechts University Kiel, Leibnizstrasse 15, D-24098 Kiel (Germany); Ivanov, Y.B. [National Research Center ' ' Kurchatov Institute' ' , Kurchatov Sq. 1, 123182 Moscow, Russia, National Research Nuclear University ' ' MEPhI' ' , Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Ilgenfritz, E.M. [Joint Institute for Nuclear Reseach, Joliot-Curie str. 6, Dubna, 141980, Moscow Region (Russian Federation)
2015-02-01
Based on the constituent quasiparticle model of the quark-gluon plasma (QGP), color quantum path-integral Monte-Carlo (PIMC) calculations of the thermodynamic properties of the QGP are performed. We extend our previous zero chemical potential simulations to the QGP at finite baryon chemical potential. The results indicate that color PIMC can be applied not only above the QCD critical temperature T{sub c} but also below T{sub c}. Besides reproducing the lattice equation of state our approach yields also valuable additional insight into the internal structure of the QGP, via the pair distribution functions of the various quasiparticles. In particular, the pair distribution function of gluons reflects the existence of gluon-gluon bound states at low temperatures and μ = 175 MeV, i.e. glueballs, while meson-like bound states are not found. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Akamatsu, Yukinao; Nonaka, Chiho; Takamoto, Makoto
2013-01-01
In this article, we present a state-of-the-art algorithm for solving the relativistic viscous hydrodynamic equation with QCD equation of state. The numerical method is based on the second-order Godunov method and has less numerical dissipation, which are crucial in describing of quark-gluon plasma in high energy heavy-ion collisions. We apply the algorithm to several numerical test problems such as sound wave propagation, shock tube and blast wave problems. In the sound wave propagation, the intrinsic {\\em numerical} viscosity is measured and its explicit expression is shown, which is the second-order of spatial resolution both in the presence and absence of {\\em physical} viscosity. The expression of the numerical viscosity can be used to determine the maximum cell size in order to accurately measure the effect of physical viscosity in the numerical simulation.
Cao, Shanshan; Qin, Guang-You; Wang, Xin-Nian
2016-01-01
A Linearized Boltzmann Transport (LBT) model coupled with hydrodynamical background is established to describe the evolution of jet shower partons and medium excitations in high energy heavy-ion collisions. We extend the LBT model to include both elastic and inelastic processes for light and heavy partons in the quark-gluon plasma. A hybrid model of fragmentation and coalescence is developed for the hadronization of heavy quarks. Within this framework, we investigate how heavy flavor observables depend on various ingredients, such as different energy loss and hadronization mechanisms, the momentum and temperature dependences of the transport coefficients, and the radial flow of the expanding fireball. Our model calculations show good descriptions of $D$ meson suppression and elliptic flow observed at the LHC and RHIC. The prediction for the Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}}$=5.02 TeV is provided.
Where does the rho go? Chirally symmetric vector mesons in the quark-gluon plasma
Pisarski, R D
1995-01-01
If the phase transition of QCD at nonzero temperature is dominated by the (approximate) restoration of chiral symmetry, then the transition might be characterized using a gauged linear sigma model. Assuming that vector meson dominance holds, such sigma models predict that at the temperature of chiral restoration, the pole mass of the thermal \\rho meson is greater than that at zero temperature; in the chiral limit and in weak coupling this mass is \\sim 962 \\, MeV. The width of the thermal \\rho-a_1 peak is estimated to be about 200 - 250 \\, MeV.
Bernhard, Jonah E; Bass, Steffen A; Liu, Jia; Heinz, Ulrich
2016-01-01
We quantitatively estimate properties of the quark-gluon plasma created in ultra-relativistic heavy-ion collisions utilizing Bayesian statistics and a multi-parameter model-to-data comparison. The study is performed using a recently developed parametric initial condition model, TRENTO, which interpolates among a general class of particle production schemes, and a modern hybrid model which couples viscous hydrodynamics to a hadronic cascade. We calibrate the model to multiplicity, transverse momentum, and flow data and report constraints on the parametrized initial conditions and the temperature-dependent transport coefficients of the quark-gluon plasma. We show that initial entropy deposition is consistent with a saturation-based picture, extract a relation between the minimum value and slope of the temperature-dependent specific shear viscosity, and find a clear signal for a nonzero bulk viscosity.
Quark-Gluon Plasma in a Bag Model with a Soft Surface
Jacobsen, Rafael B.; Marranghello, Guilherme F.; Vasconcellos, César A. Z.; Mesquita, Alexandre
We analyze the implications of quantum hadrodynamics (QHD) and quantum chromodynamics (QCD) to model, respectively, two distinct phases of nuclear matter, a baryon-meson phase and a quark-gluon phase. We develop an equation of state (EoS) in the framework of a quark-meson coupling model for the hadron-meson phase using a new version of the fuzzy bag model with scalar-isoscalar, vector-isoscalar and vector-isovector meson-quark couplings and leptonic degrees of freedom as well as the constrains from chemical equilibrium, baryon number and electric charge conservation. We model the EoS for the QGP phase for asymptotically free massless quarks and gluons using the MIT approach and a temperature and baryon chemical potential dependent bag constant, B(T,μ), which allows an isentropic equilibrium phase transition from a QGP to a hadron gas as determined by thermodynamics. Our predictions yield the EoS and static global properties of neutron stars and protoneutron stars at low and moderate values of temperature. Our results are slightly modified in comparison to predictions based on the standard MIT bag model with a constant bag pressure B.
Equation of State for a Quark Gluon Plasma in the Fuzzy Bag Model
Jacobsen, R. B.; Vasconcellos, C. A. Z.; Bodmann, Bardo E. J.; Dillig, Manfred
2004-12-01
We study two distinct phases of nuclear matter, a baryon-meson phase and a quark-gluon phase (QGP). For the baryon-meson phase we develop an equation of state (EoS) using a quark-meson formulation based on a new version of the fuzzy bag model with scalar-isoscalar, vector-isoscalar and vector-isovector meson-quark couplings and leptonic degrees of freedom as well as the constraints of chemical equilibrium, baryon number and electric charge conservation. For the QGP phase we model an EoS for asymptotically free massless quarks and gluons using the MIT approach and a temperature and baryon chemical potential dependent bag constant, B(T,μ), which allows an isentropic equilibrium phase transition from a QGP to a hadron gas. Our main results indicate the EoS and static global properties of neutron stars and protoneutron stars at low and moderate values of temperature are slightly modified in comparison to the predictions based on the MIT bag model with a constant B.
Relating $\\hat{q}$, $\\eta/s$ and $\\Delta E$ in an expanding Quark-Gluon Plasma
Ayala, Alejandro; Jalilian-Marian, Jamal; Tejeda-Yeomans, Maria Elena
2016-01-01
We use linear viscous hydrodynamics to describe the energy and momentum deposited by a fast moving parton in a quark gluon plasma. This energy-momentum is in turn used to compute the probability density for the production of soft partons by means of the Cooper-Frye formula. We use this probability density to render manifest a relation between the average transverse momentum given to the fast moving parton from the medium $\\hat{q}$, the entropy density to shear viscosity ratio $\\eta/s$ and the energy lost by the fast moving parton $\\Delta E$ in an expanding medium under similar conditions to those generated in nucleus-nucleus collisions at the LHC. We find that $\\hat{q}$ increases linearly with $\\Delta E$ for both trigger and away side partons that have been produced throughout the medium. On the other hand, $\\eta/s$ is more stable with $\\Delta E$. We also study how these transport coefficients vary with the geometrical location of the hard scattering that produces the fast moving partons. The behavior of $\\ha...
Static quark-antiquark potential in the quark-gluon plasma from lattice QCD.
Burnier, Yannis; Kaczmarek, Olaf; Rothkopf, Alexander
2015-02-27
We present a state-of-the-art determination of the complex valued static quark-antiquark potential at phenomenologically relevant temperatures around the deconfinement phase transition. Its values are obtained from nonperturbative lattice QCD simulations using spectral functions extracted via a novel Bayesian inference prescription. We find that the real part, both in a gluonic medium, as well as in realistic QCD with light u, d, and s quarks, lies close to the color singlet free energies in Coulomb gauge and shows Debye screening above the (pseudo)critical temperature T_{c}. The imaginary part is estimated in the gluonic medium, where we find that it is of the same order of magnitude as in hard-thermal loop resummed perturbation theory in the deconfined phase.
Hydrodynamic transport coefficients for the non-conformal quark-gluon plasma from holography
Finazzo, Stefano I; Marrochio, Hugo; Noronha, Jorge
2014-01-01
In this paper we obtain holographic formulas for the transport coefficients $\\kappa$ and $\\tau_\\pi$ present in the second-order derivative expansion of relativistic hydrodynamics in curved spacetime associated with a non-conformal strongly coupled plasma described holographically by an Einstein+Scalar action in the bulk. We compute these coefficients as functions of the temperature in a bottom-up non-conformal model that is tuned to reproduce lattice QCD thermodynamics at zero baryon chemical potential. We directly compute, besides the speed of sound, 6 other transport coefficients that appear at second-order in the derivative expansion. We also give an estimate for the temperature dependence of 11 other transport coefficients taking into account the simplest contribution from non-conformal effects that appear near the QCD crossover phase transition. Using these results, we construct an Israel-Stewart-like theory in flat spacetime containing 13 of these 17 transport coefficients that should be suitable for ph...
Topological String in Quantum-Chromodynamical Chiral Phase Transitions
Institute of Scientific and Technical Information of China (English)
LI Yun-De
2005-01-01
@@ It is pointed out that if in heavy ion collision processes, the quark-gluon plasma SU(2) chiral phase transition really takes place and the phase transition is a second order. Then the topological string, i.e., the π string, will be formed. The main effect of this phenomenon is that there will be a number of pions produced by decay of the π string in the final state. The pions from the decay of the π string lead to the same effect of decreasing the Hanbury-Brown-Twiss peak in two-pion spectra which is just as that of the long-lived hadronic resonances.At relativistic heavy-ion collision and large hadron collision energies, it is expected that the factors are about α～ 0.7 - 0.9 and α～ 0.6 - 0.85, respectively.
Collapse of Flow: Probing the Order of the Phase Transition
Stöcker, Horst
2007-01-01
We discuss the present collective flow signals for the phase transition to the quark-gluon plasma (QGP) and the collective flow as a barometer for the equation of state (EoS). We emphasize the importance of the flow excitation function from 1 to $50 A$ GeV: here the hydrodynamic model has predicted the collapse of the $v_1$-flow at $\\sim 10 A$ GeV and of the $v_2$-flow at $\\sim 40 A$ GeV. In the latter case, this has recently been observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy, we interpret this observation as potential evidence for a first order phase transition at high baryon density $\\rho_B$.
"Chemical" composition of the Quark-Gluon Plasma in relativistic heavy-ion collisions
Scardina, F; Plumari, S; Greco, V
2012-01-01
We study the evolution of the quark-gluon composition of the plasma created in ultra-Relativistic Heavy Ion Collisions (uRHIC's) employing a partonic transport theory that includes both elastic and inelastic collisions plus a mean fields dynamics associated to the widely used quasi-particle model. The latter, able to describe lattice QCD thermodynamics, implies a "chemical" equilibrium ratio between quarks and gluons strongly increasing as $T\\rightarrow T_c$, the phase transition temperature. Accordingly we see in realistic simulations of uRHIC's a rapid evolution from a gluon dominated initial state to a quark dominated plasma close to $T_c$. The quark to gluon ratio can be modified by about a factor of $\\sim 20$ in the bulk of the system and appears to be large also in the high $p_T$ region. We discuss how this aspect, often overflown, can be essential for a quantitative study of several key issues in the QGP physics: shear viscosity, jet quenching, quarkonia suppression. Furthemore a bulk plasma made by mo...
Bridging soft-hard transport properties of quark-gluon plasmas with CUJET3.0
Energy Technology Data Exchange (ETDEWEB)
Xu, Jiechen [Department of Physics, Columbia University,538 West 120th Street, New York, NY 10027 (United States); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University,2401 North Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Brookhaven National Laboratory,Building 510A, Upton, NY 11973 (United States); Gyulassy, Miklos [Department of Physics, Columbia University,538 West 120th Street, New York, NY 10027 (United States)
2016-02-25
A new model (CUJET3.0) of jet quenching in nuclear collisions coupled to bulk data constrained (VISH2+1D) viscous hydrodynamic backgrounds is constructed by generalizing the perturbative QCD based (CUJET2.0) model to include two complementary non-perturbative chromodynamical features of the QCD confinement cross-over phase transition near T{sub c}≈160 MeV: (1) the suppression of quark and gluon chromo-electric-charged (cec) degrees of freedom and (2) the emergence of chromo-magnetic-monopole (cmm) degrees of freedom. Such a semi Quark Gluon Monopole Plasma (sQGMP) microscopic scenario is tested by comparing predictions of the leading hadron nuclear modification factors, R{sub AA}{sup h}(p{sub T}>10GeV/c,√s), and their azimuthal elliptic asymmetry v{sub 2}{sup h}(p{sub T}>10GeV/c,√s) with available data on h=π,D,B jet fragments from nuclear collisions at RHIC(√s=0.2 ATeV) and LHC(√s=2.76 ATeV). The cmm degrees of freedom in the sQGMP model near T{sub c} are shown to solve robustly the long standing R{sub AA} vs v{sub 2} puzzle by predicting a maximum of the jet quenching parameter field q̂(E,T)/T{sup 3} near T{sub c}. The robustness of CUJET3.0 model to a number of theoretical uncertainties is critically tested. Moreover the consistency of jet quenching with observed bulk perfect fluidity is demonstrated by extrapolating the sQGMP q̂ down to thermal energy E∼3T scales and showing that the sQGMP shear viscosity to entropy density ratio η/s≈T{sup 3}/q̂ falls close to the unitarity bound, 1/4π, in the range (1−2)T{sub c}. Detailed comparisons of the CUJET2.0 and CUJET3.0 models reveal the fact that remarkably different q̂(T) dependence could be consistent with the same R{sub AA} data and could only be distinguished by anisotropy observables. These findings demonstrate clearly the inadequacy of focusing on the jet path averaged quantity 〈q̂〉 as the only relevant medium property to characterize jet quenching, and point to the crucial roles of
The role of noise and dissipation in the hadronization of the quark-gluon plasma
Fraga, E S
2006-01-01
We discuss the role of noise and dissipation in the explosive spinodal decomposition scenario of hadron production during the chiral transition after a high-energy heavy ion collision. We use a Langevin description inspired by nonequilibrium field theory to perform real-time lattice simulations of the behavior of the chiral fields. Preliminary results for the interplay between additive and multiplicative noise terms, as well as for non-Markovian corrections, are also presented.
A chiral matrix model of the semi-Quark Gluon Plasma in QCD
Pisarski, Robert D
2016-01-01
A chiral matrix model applicable to QCD with 2+1 flavors is developed. This requires adding a SU(3)_L x SU(3)_R x Z(3)_A nonet of scalar fields, with both parities, and coupling these to quarks through a Yukawa coupling, y. Treating the scalar fields in mean field approximation, the effective Lagrangian is computed by integrating out quarks to one loop order. In addition to the usual symmetry breaking term, linear in the current quark mass m_qk, at a nonzero temperature T it is necessary to add a new term, ~ m_qk T^2. The parameters of the gluon part of the matrix model, including especially the deconfining transition temperature T_d = 270 MeV, are identical to that for the pure glue theory without quarks. The parameters in the chiral matrix model are fixed by the values, at zero temperature, of the pion decay constant the masses of the pions, kaons, eta, and eta'. The temperature for the chiral crossover at T_chi = 155 MeV is determined by adjusting the Yukawa coupling y. We find reasonable agreement with th...
Searching for Quark-Gluon Plasma(QGP) Bubble effects at RHIC/LHC
Lindenbaum, S J; Longacre, R S; 10.1140/epjc/s2003-01268-3
2003-01-01
Since the early eighties, we have shared with Leon Van Hove the following view. That if a QGP were produced in high energy heavy ion colliders, that its hadronization products would likely come from small localized in phase space bubbles of plasma. We develop a model based on HIJING, to which we added a ring of adjoining multiple bubbles in the central rapidity region. Our simulations were designed to be tested by the forthcoming RHIC STAR detector data for 65 GeV/n Au colliding with 65 GeV/n Au. We took into account background and resonance effects to allow a direct comparison with the data. Later 100 GeV/n Au colliding with 100 GeV/n Au and LHC data could also test these ideas. We used two charged particle correlation's as a sensitive method to test for bubbles.
The errant life of a heavy quark in the quark-gluon plasma
Meyer, Harvey B
2010-01-01
In the high-temperature phase of QCD, the heavy quark momentum diffusion constant determines, via a fluctuation-dissipation relation, how fast a heavy quark kinetically equilibrates. This transport coefficient can be extracted from thermal correlators via a Kubo formula. We present a lattice calculation of the relevant Euclidean correlators in the gluon plasma, based on a recent formulation of the problem in heavy-quark effective field theory (HQET). We find a $\\approx20%$ enhancement of the Euclidean correlator at maximal time separation as the temperature is lowered from $6T_c$ to $2T_c$, pointing to stronger interactions at lower temperatures. At the same time, the correlator becomes flatter from $6T_c$ down to $2T_c$, indicating a relative shift of the spectral weight to lower frequencies. A recent next-to-leading order perturbative calculation of the correlator agrees with the time dependence of the lattice data at the few-percent level. We estimate how much additional contribution from the $\\omega\\lesss...
Phase transitions, nonequilibrium dynamics, and critical behavior of strongly interacting systems
Energy Technology Data Exchange (ETDEWEB)
Mottola, E.; Bhattacharya, T.; Cooper, F. [and others
1998-12-31
This is the final report of a three-year, Laboratory Directed Research and Development project at Los Alamos National Laboratory. In this effort, large-scale simulations of strongly interacting systems were performed and a variety of approaches to the nonequilibrium dynamics of phase transitions and critical behavior were investigated. Focus areas included (1) the finite-temperature quantum chromodynamics phase transition and nonequilibrium dynamics of a new phase of matter (the quark-gluon plasma) above the critical temperature, (2) nonequilibrium dynamics of a quantum fields using mean field theory, and (3) stochastic classical field theoretic models with applications to spinodal decomposition and structural phase transitions in a variety of systems, such as spin chains and shape memory alloys.
Energy Technology Data Exchange (ETDEWEB)
Guerin, Fabien [Ecole Doctorale des Sciences Fondamentales, Universite Blaise Pascal, U.F.R de Recherches Scientifiques et Techniques, 34, avenue Carnot - BP 185, 63006 Clermont-Ferrand Cedex (France)
2006-11-15
ALICE (A Large Ion Collider Experiment) is the LHC detector dedicated to the study of ultra-relativistic heavy ion collisions. The main goal of ALICE is the study of a new phase of the nuclear matter predicted by the Quantum Chromodynamics theory (QCD): the Quark-Gluon Plasma (QGP). One of the possible signatures is a suppression of quarkonia yields by color screening in the heavy ion collisions, in which the formation of the QGP is expected. The muon spectrometer will allow measuring of the quarkonia yields (J/{psi}, {upsilon}) in heavy ion collisions via their dimuon decay. A fast trigger, associated to muon spectrometer, has to select events with at least one muon or one dimuon by using a track search algorithm. The study of muon trigger performance will be presented with emphasis on the trigger efficiency and rates in Ar-Ar and Pb-Pb collisions. We will also present the reconstruction of unlike-sign dimuon mass spectrum with the ALICE muon spectrometer. The expected yields of Upsilon states will be extracted from a simulation based on a fit of this spectrum for one month running for Pb-Pb collisions and for different collision centralities. (author)
Hedgehogs in Wilson loops and phase transition in SU(2) Yang-Mills theory
Belavin, V A; Kozlov, I E
2006-01-01
We suggest that the gauge-invariant hedgehogs-like structures in the Wilson loops are physically interesting degrees of freedom in the Yang-Mills theory. The trajectories of these hedgehogs are closed curves which correspond to center-valued (untraced) Wilson loops and are characterized by the center charge and by the winding number. We show numerically in SU(2) Yang-Mills theory that the density of the hedgehogs in the thermal Wilson-Polyakov line is very sensitive to the finite temperature phase transition. The (additively normalized) hedgehog density behaves as an order parameter: the density is almost independent of the temperature in the confinement phase and changes substantially as the system gets into the deconfinement phase. Our results suggest in particular that the (static) hedgehogs may be relevant degrees of freedom around the deconfinement transition, and thus affect evolution of the quark-gluon plasma in high-energy heavy ion collisions.
Hedgehogs in Wilson loops and phase transition in SU(2) Yang-Mills theory
Energy Technology Data Exchange (ETDEWEB)
Belavin, V.A. [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, RU-117259 Moscow (Russian Federation); Chernodub, M.N. [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, RU-117259 Moscow (Russian Federation) and Department of Theoretical Physics, Uppsala University, P.O. Box 803, S-75108 Uppsala (Sweden)]. E-mail: maxim.chernodub@itep.ru; Kozlov, I.E. [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, RU-117259 Moscow (Russian Federation); Faculty of Physics, Moscow State University, RU-119992 Moscow (Russian Federation)
2006-08-07
We suggest that the gauge-invariant hedgehog-like structures in the Wilson loops are physically interesting degrees of freedom in the Yang-Mills theory. The trajectories of these 'hedgehog loops' are closed curves corresponding to center-valued (untraced) Wilson loops and are characterized by the center charge and winding number. We show numerically in the SU(2) Yang-Mills theory that the density of hedgehog structures in the thermal Wilson-Polyakov line is very sensitive to the finite-temperature phase transition. The (additively normalized) hedgehog line density behaves like an order parameter: The density is almost independent of the temperature in the confinement phase and changes substantially as the system enters the deconfinement phase. In particular, our results suggest that the (static) hedgehog lines may be relevant degrees of freedom around the deconfinement transition and thus affect evolution of the quark-gluon plasma in high-energy heavy-ion collisions.
Test of Quark-Gluon Plasma of Cylindrical Shape by Two-Pion Interferometry%柱形夸克胶子等离子体的2π干涉学检测
Institute of Scientific and Technical Information of China (English)
陈小凡; 杨学栋; 韩玲
2006-01-01
在2π干涉学中,对不同的π源,2π关联函数可以是不同的.如果在相对论重离子碰撞中出现柱形夸克胶子等离子体,π介子将从柱形夸克胶子等离子体表面发射,此时2π关联函数将出现一种特殊的振荡行为.这种振荡行为可以用来探明夸克胶子等离子体的存在性,同时也是相对论重离子碰撞中出现夸克胶子等离子体的一个信号.%The two-pion correlation functions are different for some pion source distributions in two-pion interferometry. If quark-gluon plasma of cylindrical shape is produced in relativistic heavy ion collisions,the pion mesons will emit from the surface of quark-gluon plasma of cylindrical shape and the corresponding correlation function will have a special oscillation behavior. The oscillation behavior can be used to verify the existence of quark-gluon plasma and is also a signature of the appearance of quark-gluon plasma.
Bubble dynamics and the quark-hadron phase transition in nuclear collisions
Fogaça, D A; Fariello, R; Navarra, F S
2016-01-01
We study the nucleation of a quark gluon plasma (QGP) phase in a hadron gas at low temperatures and high baryon densities. This kind of process will presumably happen very often in nuclear collisions at FAIR and NICA. When the right energy density (or baryon density) is reached the conversion of one phase into another is not instantaneous. It is a complex process, which involves the nucleation of bubbles of the new phase. One important element of this transition process is the rate of growth of a QGP bubble. In order to estimate it we solve the Relativistic Rayleigh$-$Plesset equation which governs the dynamics of a relativistic spherical bubble in a cold and strongly interacting medium. The baryon rich hadron gas is represented by the nonlinear Walecka model and the QGP is described by the MIT bag model and also by a mean field model of QCD.
Berges, Jürgen; Reygers, Klaus; Tanji, Naoto; Venugopalan, Raju
2017-05-01
Recent classical-statistical numerical simulations have established the "bottom-up" thermalization scenario of Baier et al. [Phys. Lett. B 502, 51 (2001), 10.1016/S0370-2693(01)00191-5] as the correct weak coupling effective theory for thermalization in ultrarelativistic heavy-ion collisions. We perform a parametric study of photon production in the various stages of this bottom-up framework to ascertain the relative contribution of the off-equilibrium "glasma" relative to that of a thermalized quark-gluon plasma. Taking into account the constraints imposed by the measured charged hadron multiplicities at Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), we find that glasma contributions are important especially for large values of the saturation scale at both energies. These nonequilibrium effects should therefore be taken into account in studies where weak coupling methods are employed to compute photon yields.
Lacey, Roy A.; Reynolds, D.; Taranenko, A.; Ajitanand, N. N.; Alexander, J. M.; Liu, Fu-Hu; Gu, Yi; Mwai, A.
2016-10-01
It is shown that the acoustic scaling patterns of anisotropic flow for different event shapes at a fixed collision centrality (shape-engineered events), provide robust constraints for the event-by-event fluctuations in the initial-state density distribution from ultrarelativistic heavy ion collisions. The empirical scaling parameters also provide a dual-path method for extracting the specific shear viscosity {(η /s)}{QGP} of the quark-gluon plasma (QGP) produced in these collisions. A calibration of these scaling parameters via detailed viscous hydrodynamical model calculations, gives {(η /s)}{QGP} estimates for the plasma produced in collisions of Au + Au (\\sqrt{{s}{NN}}=0.2 {TeV}) and Pb + Pb (\\sqrt{{s}{NN}}=2.76 {TeV}). The estimates are insensitive to the initial-state geometry models considered.
Sokolov, V. V.; Vlasyuk, V. V.; Petkov, V. B.
2016-06-01
The International Workshop on Quark Phase Transition in Compact Objects and Multimessenger Astronomy: Neutrino Signals, Supernovae and Gamma-Ray Bursts (October, 7-14, 2015) was dedicated to Quantum ChromoDynamics (QCD) Phase Transitions and observational signals of these transitions related to formation of compact astrophysical objects. The aim of this workshop was to bring together researchers working on the problems of behavior of matter under critical conditions achievable in such astrophysical objects as "strange" or "hybrid" stars and in laboratories at heavy-ion collisions to discuss fundamental issues and recent developments. Topics included both observations (radio, optical and X-ray astronomy, gamma ray bursts, gravitational waves, neutrino detection, heavy-ion collisions, etc.) and theory (supernova simulations, proto-neutron and neutron stars, equation of state of dense matter, neutron star cooling, unstable modes, nucleosynthesis, explosive transitions, quark-gluon plasma).
Energy Technology Data Exchange (ETDEWEB)
Rafelski, Johann [CERN-PH/TH, Geneva 23 (Switzerland); The University of Arizona, Department of Physics, Tucson, Arizona (United States)
2015-09-15
Two phases of hot hadronic matter are described with emphasis put on their distinction. Here the role of strange particles as a characteristic observable of the quark-gluon plasma phase is particularly explored. (orig.)
Pion Interferometry for Cylindrical Quark-Gluon Plasma Evolution Sources%柱形夸克-胶子等离子体演化源的π干涉学分析
Institute of Scientific and Technical Information of China (English)
Efaaf M.J.; 张卫宁; Khaliliasr M.; 霍雷; 金恩培; 张景波
2005-01-01
本文对Bjorken柱形夸克-胶子等离子体演化膨胀源进行了2π Hanbury-Brown-Twiss(HBT)干涉学分析.利用量子几率振幅的路径积分公式计算2π HBT关联函数并得到对膨胀和静态源的HBT半径.研究发现,在冻结发射情况下的HBT半径要明显大于没有考虑多重散射吸收情况下的结果,源的膨胀速度导致HBT半径变小.对相变温度宽度为零的Bjorken柱形源,膨胀速度的影响要小于对应的球形源的结果.%We examine the two-pion Hanbury-Brown-Twiss(HBT) interferometry for the expanding sources of quark-gluon plasma evolution with the Bjorken cylinder geometry. The two-pion HBT correlation functions are calculated using quantum probability amplitudes in a path-integral formalism and the HBT radius is extracted both for the expanding source and the static source.We find that the HBT radius for the freeze-out emission case is substantially greater than that for the case without absorption of multiple scattering. The expanding velocity of the source leads to a smaller HBT radius.The effect of expanding velocity for the Bjorken cylinder source with zero width of the transition temperature is smaller than those of the corresponding spherical source.
球形夸克-胶子等离子体演化源的π干涉学分析%Pion Interferometry for Spherical Quark-Gluon Plasma Evolution Sources
Institute of Scientific and Technical Information of China (English)
Efaaf M.J.; 张卫宁; Khaliliasr M.; 金恩培; 刘亦铭
2005-01-01
We examine the two-pion interferometry for the expanding sources of spherical quark-gluon plasma evolution. The quarkgluon plasma evolution is described by relativistic hydrodynamics with the equation of state of entropy density. The two-pion HanburyBrown-Twiss (HBT) correlation functions are calculated using quantum probability amplitudes in a path-integral formalism. We find the spatial parameter extracted by the two-pion interferometry is sensitive to the phase-space distribution of the pion-emitting source.The expanding velocity of the source leads to a smaller HBT radius and changes the relationship between the HBT radius and the freeze-ont temperature.%本文对球形演化的夸克-胶子等离子体膨胀源进行了2π干涉学分析.夸克-胶子等离子体的演化由相对论流体力学和熵密度的物态方程描述,而2πHanbury-Brown-Twiss(HBT)关联函数由量子几率振幅的路径积分公式计算.研究结果表明,由2π干涉学得到的源的空间参量敏感地依赖于π介子发射源的相空间分布,源的膨胀速度导致HBT半径变小,并会改变HBT半径与冻结温度之间的关系.
Quark-hadron phase transition and strangeness conservation constraints
Saeed-Uddin
1999-01-01
The implications of the strangeness conservation in a hadronic resonance gas (HRG) on the expected phase transition to the quark gluon plasma (QGP) are investigated. It is assumed that under favourable conditions a first order hadron-quark matter phase transition may occur in the hot hadronic matter such as those produced in the ultra-relativistic heavy-ion collisions at CERN and BNL. It is however shown that the criteria of strict strangeness conservation in the HRG may not permit the occurrence of a strict first order equilibrium quark-hadron phase transition unlike a previous study. This emerges as a consequence of the application of a realistic equation of state (EOS) for the HRG and QGP phases, which account for the finite-size effect arising from the short range hard-core hadronic repulsion in the HRG phase and the perturbative QCD interactions in the QGP phase. For a first order hadron-quark matter phase transition to occur one will therefore require large fluctuations in the critical thermal parameters, which might arise due to superheating, supercooling or other nonequlibrium effects. We also discuss a scenario proposed earlier, leading to a possible strangeness separation process during hadronization.
Mamo, Kiminad A
2016-01-01
We show that a massless quark moving at the speed of light $v=1$, in arbitrary direction, in a strongly coupled $\\mathcal{N}=4$ super Yang-Mills (SYM) vacuum in the presence of strong magnetic field $\\mathcal{B}$, losses its energy at a rate linearly dependent on $\\mathcal{B}$, i.e., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$. In addition, we show that a heavy quark of mass $M$ moving at near the speed of light $v^2=v_{*}^2=1-\\frac{4\\pi^2 T^2}{\\mathcal{B}}\\simeq1$, in arbitrary direction, in a strongly coupled $\\mathcal{N}=4$ SYM quark-gluon plasma at finite temperature $T$, in the presence of strong magnetic field $\\mathcal{B}\\gg T^2$, losses its energy at a rate linearly dependent on $\\mathcal{B}$, i.e., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}v_{*}^2\\simeq-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$.
Effect of extrinsic curvature on quark--hadron phase transition
Heydari-Fard, Malihe
2009-01-01
The last phase transition predicted by the standard model of particle physics took place at the QCD scale $T\\sim200$ MeV when the universe was about $t\\sim10^{-5}$ seconds old and the Hubble radius was around 10 Km. In this paper, we consider the quark--hadron phase transition in the context of brane-world cosmology where our universe is a 3-brane embedded in a $m$-dimensional bulk and localization of matter on the brane is achieved by means of a confining potential. We study the behavior of the physical quantities relevant to the description of the early universe like the energy density, temperature and scale factor, before, during, and after the phase transition and investigate the effects of extrinsic curvature on the cosmological phase transition. We show that the brane-world effects reduce the effective temperature of the quark--gluon plasma and of the hadronic fluid. Finally, we discuss the case where the universe evolved through a mixed phase with a small initial supercooling and monotonically growing ...
Overview of results from phase I of the Beam Energy Scan program at RHIC
Directory of Open Access Journals (Sweden)
McDonald Daniel
2015-01-01
Full Text Available The first phase of the Beam Energy Scan (BES program at the Relativistic Heavy Ion Collider (RHIC was successfully completed during the years 2010, 2011 and 2014, with Au+Au collisions at center-of-mass energies (√sNN of 7.7, 11.5, 14.5, 19.6, 27, and 39 GeV. The BES has three distinct goals: search for the turning off of the signatures of the Quark Gluon Plasma (QGP, search for the first-order phase transition, and search for the critical point. We report several interesting results that address each of these goals of the BES program.
Mathews, Grant J.; Meixner, Matthew; Olson, J. Pocahontas; Lan, Nguyen Q.; Dalhed, Holister E.
2013-10-01
We present an updated and improved equation of state (which we call the NDL EoS) for use in neutron-star structure and core-collapse supernova simulations. This EoS is begins with a framework originally developed by Bowers & Wilson, but there are numerous changes. Among them are: (1) a reformulation in the context of density functional theory; (2) the possibility of the formation of material with a net proton excess (Ye > 0 . 5); (3) an improved treatment of the nuclear statistical equilibrium and the transition to heavy nuclei as the density approaches nuclear matter density; (4) an improved treatment of the effects of pions in the regime above nuclear matter density including the incorporation of all the known mesonic and baryonic states at high temperature; (5) the effects of 3-body nuclear forces at high densities; and (6) the possibility of a first-order or crossover transition to a QCD chiral symmetry restoration and deconfinement phase at densities above nuclear matter density. This paper details the physics of, and constraints on, this new EoS and describes its implementation in numerical simulations. We show comparisons of this EoS with other equations of state commonly used in supernova collapse simulations. Work at the University of Notre Dame is supported by the U.S. Department of Energy under Nuclear Theory Grant DE-FG02-95-ER40934.
Phase Diagram in Quantum Chromodynamics
Apostol, M
2013-01-01
It is suggested that the hadronization of the quark-gluon plasma is a first-order phase transition described by a critical curve in the temperature-(quark) density plane which terminates in a critical point. Such a critical curve is derived from the van der Waals equation and its parameters are estimated by using the theoretical approach given in M. Apostol, Roum. Reps. Phys. 59 249 (2007); Mod. Phys. Lett. B21 893 (2007). The main assumption is that quark-gluon plasma created by high-energy nucleus-nucleus collisions is a gas of ultrarelativistic quarks in equilibrium with gluons (vanishing chemical potential, indefinite number of quarks). This plasma expands, gets cool and dilute and hadronizes at a certain transition temperature and transition density. The transition density is very close to the saturation density of the nuclear matter and, it is suggested that both these points are very close to the critical point n~1fm^{-3} (quark density) and T~200MeV (temperature).
A Model Study Of The Deconfining Phase Transition
Velytsky, A
2004-01-01
The study of the deconfining phase transition or crossover is important for the understanding of properties of nuclear matter and the quark gluon plasma. Heavy ion collisions experiments are capable of creating conditions necessary for deconfinement. The dynamics of this process and not only its equilibrium properties are of interest. In this dissertation non-equilibrium aspects of rapid heating and cooling of the QCD vacuum are studied in a model framework. The 3-D Potts model with an external magnetic field is an effective model of QCD (of pure SU(3) gauge theory, when the magnetic field is set to zero), which we study by means of Monte Carlo simulations. Other models are used to understand the influence of the strength of the phase transition. In our investigations these systems are temperature driven through a phase transition or a rapid crossover using updating procedures in the Glauber universality class. We study hysteresis cycles with different updating speeds and simulations of a quench. Qualitativel...
Nuclear Matter Phase Transition in Infinite and Finite Systems
Terranova, S.; Bonasera, A.
2005-04-01
A new "semiclassical" model of the nuclear matter, composed of u, d colored quarks, is proposed. The approach, named Constrained Molecular Dynamics (CoMD) is based on the molecular dynamics simulation of the quarks, which interact through the Richardson's potential, and on a constraint due to Pauli blocking. With a suitable choice of the quark masses, some possible Equation of State (EOS) of the nuclear matter, at temperature equal to zero and finite baryon density, are obtained. These equations of state, not only present some known properties of the nuclear matter, as the Quark-Gluon Plasma (QGP) phase transition, but also shown the existence of a new state, the Exotic Color Clustering (ECC) state, in which cluster of quarks with the same color are formed. Some new quantities, "indicators" of the phase transition, are introduced: three order parameters, Mc2, Mc3, Mc4 defined trough the Gell-Mann matrices λα, and the lifetime of the J/Ψ particle. The behavior of the J/Ψ particle is studied also in the "finite" systems, obtained by expanding the corresponding "infinite" systems. It seems that the dynamics and the finite size effects do not wash completely the phase transition occurred in infinite systems, and the J/Ψ particle is still a good signature.
The interfacial surface tension of a quark-gluon plasma ﬁreball in a hadronic medium
Indian Academy of Sciences (India)
R Ramanathan; K K Gupta; Agam K Jha; S S Singh
2007-05-01
We calculate the interfacial surface tension of a QGP-ﬁreball in a hadronic medium in the Ramanathan et al statistical model. The constancy of the ratio of the surface tension with the cube of the critical transition temperature is in overall accordance with lattice QCD ﬁndings. It is in complete agreement with a recent MIT bag model calculation of surface tension. The velocity of sound in the QGP droplet is predicted to be in the range (0.27 ± 0.02) times the velocity of light in vacuum and this value is independent of both the value of the transition temperature and the model parameters.
Jiang, Zhi-Jin; Zhang, Yu
2016-01-01
It is widely believed that the quark-gluon plasma (QGP) might be formed in heavy ion collisions. It is also widely recognized that the relativistic hydrodynamics is one of the best tools for describing the process of expansion and particlization of QGP. In this paper, one dimensional hydrodynamic model involving the phase transition from QGP state to hadronic state is used to analyze the transverse momentum spectra of identified charged particles produced in heavy ion collisions. The analytical solutions are presented. A comparison is made between the theoretical predictions and experimental data. The theoretical model works well in Au-Au collisions at sqrt(s_NN)=200 and 130 GeV at RHIC.
利用不确定性关系计算夸克-胶子等离子体的寿命%To Calculate the Lifetime of Quark-gluon Plasma with Uncertainty Relation
Institute of Scientific and Technical Information of China (English)
王栋; 傅永平
2013-01-01
In this paper, the Uncertainty Relation is used to calculate the lifetime of quark-gluon plasma, this method avoids the complicated theoretical derivation, and the physical meaning and physical process is very clear.%利用不确定性关系可以计算出夸克-胶子等离子体的寿命，这种方法既避免了复杂的理论推导，又明确了物理过程和物理意义。
Results of the NA49 experiment on the search for the quark-gluon plasma at the CERN SPS
Seyboth, P
2001-01-01
Experiment NA49 at the CERN SPS has performed large acceptance measurements of hadron production in Pb+Pb collisions at 40 and 158 A.GeV beam energies. These data allowed a study of the space-time evolution, the hadro-chemical composition and event-by-event fluctuations of average event properties of the created hadron system. Results at top SPS energy are consistent with the existence of a transient deconfined phase in the early stage of the reaction. (22 refs).
eta/s and the phase transition of the Non-Linear Sigma Model
Dobado, Antonio; Torres-Rincon, Juan M
2008-01-01
We present a calculation of eta/s for the meson gas (zero baryon number) within unitarized NLO chiral perturbation theory and confirm the observation that eta/s decreases towards the possible phase transition to a quark-gluon plasma/liquid. The value is however somewhat higher than previously estimated in LO chiPT. We then study the behavior of the viscosity over entropy density across the known second order phase transition in the Non-Linear Sigma Model, and establish that it has indeed a minimum that, within calculational uncertainties, can be identified with the phase transition. Finally we examine the case of atomic Argon gas to check the discontinuity of eta/s across a first order phase transition. Our results reinforce the possibility of employing the KSS number to pin down the phase transition and critical point to a cross-over in strongly interacting nuclear matter between the hadron gas and the quark and gluon plasma/liquid.
Institute of Scientific and Technical Information of China (English)
陈勋; 冯笙琴
2016-01-01
首先利用Woods‐Saxon分布，计算相对论重离子碰撞磁场空间分布；并在此基础上考虑夸克胶子等离子体（QGP）的响应，假定QGP为理想导体情况下，研究磁场在QGP环境下的分布特征。%Spatial distributions of magnetic field are calculated in relativistic heavy ion collision based on Woods‐Saxon dis‐tribution .We further study the characteristics of magnetic field distribution while considering Quark gluon plasma (QGP) as an ideal conductor response in a QGP environment .
Energy Technology Data Exchange (ETDEWEB)
Espagnon, B
2007-10-15
The Alice experiment is one of the four main LHC (Large Hadron Collider) experiments. It is dedicated to the study of a new state of matter: the quark gluon plasma, where quarks and gluons are no longer confined within hadrons. In this document, the physics issues that led to the construction of Alice dimuon spectrometer, are described. Then, the research and development on the dimuon spectrometer is presented. The different absorbers are described and experimental tests used to determine their dimensions are presented. The dimuon trigger built using the RPC (Resistive Plate Chamber) streamer mode is then described along with the associated beam and cosmic tests and results. Finally, the tracking system is described in detail and more particularly all its electronics and the first station. The physics constraints on the expected performances of all these systems are clearly defined. (author)
Phase structure of hadronic and Polyakov-loop extended NJL model at finite isospin density
Cavagnoli, Rafael; Providência, Constança
2013-01-01
It is believed that there exists a rich phase structure of quantum chromodynamics (QCD) at finite temperature and baryon density, namely, the deconfinement process from hadron gas to quark-gluon plasma, the transition from chiral symmetry breaking phase to the symmetry restoration phase, and the color superconductivity at low temperature and high baryon density. In the present work we study the hadron-quark phase transition by investigating the binodal surface and extending it to finite temperature in order to mimic the QCD phase diagram. In order to obtain these conditions we use different models for the two possible phases, namely the quark and hadron phases. The phase separation boundary (binodal) is determined by the Gibbs criteria for phase equilibrium. The boundaries of the mixed phase and the related critical points for symmetric and asymmetric matter are obtained. Isospin effects appear to be rather significant. The critical endpoint (CEP) and the phase structure are also studied in the Polyakov-loop ...
Khodadi, M
2014-01-01
We study the phase transition from quark-gluon plasma to hadrons in the early universe in the context of non-equilibrium thermodynamics. According to the standard model of cosmology, a phase transition associated with chiral symmetry breaking after the electro-weak transition has occurred when the universe was about $1-10\\mu s$ old. We focus attention on such a phase transition in the presence of a viscous relativistic cosmological background fluid in the framework of non-detailed balance Ho\\v{r}ava-Lifshitz cosmology within an effective model of QCD. We consider a flat Friedmann-Robertson-Walker Universe filled with a non-causal and causal bulk viscous cosmological fluid respectively and investigate the effects of the running coupling constants of Ho\\v{r}ava-Lifshitz gravity, $\\lambda$, on the evolution of the physical quantities relevant to a description of the early universe, namely, the temperature $T$, scale factor $a$, deceleration parameter $q$ and dimensionless ratio of the bulk viscosity coefficient ...
Unveiling the cosmological QCD phase transition through the eLISA/NGO detector
Roque, V R C Mourão
2013-01-01
We study the evolution of turbulence in the early universe at the QCD epoch using a state-of-the-art equation of state derived from lattice QCD simulations. Since the transition is a crossover we assume that temperature and velocity fluctuations were generated by some event in the previous history of the Universe and survive until the QCD epoch due to the extremely large Reynolds number of the primordial fluid. The fluid at the QCD epoch is assumed to be non-viscous, based on the fact that the viscosity per entropy density of the quark gluon plasma obtained from heavy-ion collision experiments at the RHIC and the LHC is extremely small. Our hydrodynamic simulations show that the velocity spectrum is very different from the Kolmogorov power law considered in studies of primordial turbulence that focus on first order phase transitions. This is due to the fact that there is no continuous injection of energy in the system and the viscosity of the fluid is negligible. Thus, as kinetic energy cascades from the larg...
Photons from Quark and Hadron Phases in Au+Au Collisions
Institute of Scientific and Technical Information of China (English)
LONG Jia-Li; HE Ze-Jun; MA Yu-Gang; GUAN Na-Na
2008-01-01
Based on a relativistic hydrodynamic model describing the evolution of the chemically equilibrating quark-gluon plasma system with finite baryon density in a 3+l-dimensional spacetime, we compute photons from the quark phase, hadronic phase and initial non-thermal contributions. It is found that due to the effects of the initial quark chemical potential, chemical equilibration and rapid expansion of the system, the photon yield of the quark-gluon plasma is strongly suppressed, and photons from hadronic matter and initial non-thermal contributions almost reproduce experimental data.
On Locating the Critical End Point in QCD Phase Diagram
Srivastava, P K; Singh, C P
2011-01-01
We use the available two different self-consistent formulations of quasiparticle models and extend their applications for the description of quark gluon plasma (QGP) at non-vanishing baryon chemical potentials. The thermodynamical quantities calculated from these models are compared with the values obtained from lattice simulations and a good agreement between theoretical calculations and lattice QCD data suggests that the values of the parameters used in the paper are consistent. A new equation of state (EOS) for a gas of extended baryons and pointlike mesons is presented here which incorporates the repulsive hard-core interactions arising due to geometrical size of baryons. A first order deconfining phase transition is constructed using Gibb's equilibrium criteria between the hadron gas EOS and quasiparticle model EOS for the weakly interacting quark matter. This leads to an interesting finding that the phase transition line ends at a critical end point beyond which a crossover region exists in the phase di...
Dynamical growth of the hadron bubbles during the quark-hadron phase transition
Shukla, P K; Sen-Gupta, S K
2001-01-01
The rate of dynamical growth of the hadron bubbles in a supercooled baryon free quark-gluon plasma, is evaluated by solving the equations of relativistic fluid dynamics in all space. For a non-viscous plasma, this dynamical growth rate is found to depend only on the range of correlation $\\xi$ of order parameter fluctuation, and the radius $R$ of the critical hadron bubble, the two length scales relevant for the description of the critical phenomena. Unlike Csernai-Kapusta result, this rate does not vanish in the limit of zero viscosity. Further, it is shown that the dynamical prefactor acquires an additive component when the medium becomes viscous. Interestingly, under certain reasonable assumption for the velocity of the sound in the medium, the viscous and the non-viscous parts of the prefactor are found to be identical to the results obtained by Csernai-Kapusta and Ruggeri-Friedman (for the case of zero viscosity) respectively. It is also demonstrated that the first order phase transition from QGP to hadro...
The QCD phase diagram from analytic continuation
Directory of Open Access Journals (Sweden)
R. Bellwied
2015-12-01
Full Text Available We present the crossover line between the quark gluon plasma and the hadron gas phases for small real chemical potentials. First we determine the effect of imaginary values of the chemical potential on the transition temperature using lattice QCD simulations. Then we use various formulas to perform an analytic continuation to real values of the baryo-chemical potential. Our data set maintains strangeness neutrality to match the conditions of heavy ion physics. The systematic errors are under control up to μB≈300 MeV. For the curvature of the transition line we find that there is an approximate agreement between values from three different observables: the chiral susceptibility, chiral condensate and strange quark susceptibility. The continuum extrapolation is based on Nt=10, 12 and 16 lattices. By combining the analysis for these three observables we find, for the curvature, the value κ=0.0149±0.0021.
The QCD phase diagram from analytic continuation
Bellwied, R; Fodor, Z; Günther, J; Katz, S D; Ratti, C; Szabo, K K
2015-01-01
We present the crossover line between the quark gluon plasma and the hadron gas phases for small real chemical potentials. First we determine the effect of imaginary values of the chemical potential on the transition temperature using lattice QCD simulations. Then we use various formulas to perform an analytic continuation to real values of the baryo-chemical potential. Our data set maintains strangeness neutrality to match the conditions of heavy ion physics. The systematic errors are under control up to $\\mu_B\\approx 300$ MeV. For the curvature of the transition line we find that there is an approximate agreement between values from three different observables: the chiral susceptibility, chiral condensate and strange quark susceptibility. The continuum extrapolation is based on $N_t=$ 10, 12 and 16 lattices. By combining the analysis for these three observables we find, for the curvature, the value $\\kappa = 0.0149 \\pm 0.0021$.
Bensalem, S.; Ait El Djoudi, A.
2016-10-01
This work deals with a statistical description of a thermally driven deconfining phase transition (DPT) from a hadronic gas consisting of massless pions to a color-singlet Quark- Gluon Plasma (QGP), in a finite volume. The thermodynamical approach, within a coexistence model is used to investigate the Quantum Chromo-Dynamics DPT occurring between the two phases, at vanishing chemical potential. Considering the color singletness condition for the QGP phase, with massless up and down quarks, the exact total partition function of the studied system is obtained and then employed to calculate mean values of physical quantities, well characterizing the system near the transition. The finite-size effects on the DPT have been investigated through the study of the thermal behavior of the order parameter, the susceptibility and the second cumulant of the probability density. The similarity between the susceptibility and the second cumulant representing the variance is probed for the studied DPT and a parameterization of the variance is proposed for the first time.
Energy Technology Data Exchange (ETDEWEB)
Zaraket, H
2000-06-01
This work is devoted to photon and dilepton production in a quark gluon plasma. The theoretical framework in which the study is carried out is Thermal Field Theory, more precisely the hard thermal loop effective theory. Several features of the observables preclude a straightforward application of the effective theory and new tools had to be developed such as the counter term method to avoid double counting. The first part of my study concerns static virtual photon production where I show that important physical contributions are missing in the effective theory at one loop level and hence a two loop calculation is indispensable. Furthermore I give an analytic leading logarithmic estimate of this two loop result showing clearly the insufficiency of the effective theory. The second part of the work focuses on real and quasi real photon production. Again, important contributions arise at two loop level due to collinear divergences. For high mass dilepton the two loop calculation is sufficient. On the other hand, near the light cone photon production rate is non perturbative. Getting closer to the light cone coherent scattering effects (Landau-Pomeranchuk-Migdal effect) arise, which imply the resummation of an infinite series of diagrams. Still nearer the light cone we found a dependence on the non perturbative magnetic mass due to infrared singularities. (author)
Test of Nonstatic Spherical Quark-Gluon Plasma by Two-Pion Interferometry%非静态球形夸克-胶子等离子体的2π干涉学的检测
Institute of Scientific and Technical Information of China (English)
陈小凡
2007-01-01
A model of expanding pion sources in relativistic heavy ion collisions, when only hadronic matter is generated, is proposed. The two-pion correlation function at small relative momentum for such a model is obtained with two-pion interferometry at small relative momentum, and the relation between the real spatial parameter Re and the apparent spatial parameter Ra of the pion sources is given. The relation is different from the one when QGP is created. The difference can be used to test nonstatic, spherical quark-gluon plasma produced in relativistic heavy ion collisions. The relation also showes a scaling behavior.%提出了一种相对论重离子碰撞中强子物质生成时的π膨胀源模型.得到了该模型中的小相对论动量区域的2π关联函数及表观π源参数Ra与实际π源参数Re的关系.这一关系与QGP生成时的关系有所区别.这一区别可以用来检测相对论重离子碰撞中产生的非静态球形夸克-胶子等离子体的存在性.两个关系也显示了一种标度行为.
Chang, Ning-Bo; Qin, Guang-You
2016-08-01
We study the evolution of the full jet shower in quark-gluon plasma by solving a set of coupled differential transport equations for the three-dimensional momentum distributions of quarks and gluons contained in full jets. In our jet evolution equations, we include all partonic splitting processes as well as the collisional energy loss and transverse momentum broadening for both the leading and radiated partons of the full jets. Combining with a realistic (2 +1 )-dimensional viscous hydrodynamic simulation for the spacetime profiles of the hot and dense nuclear medium produced in heavy-ion collisions, we apply our formalism to calculate the nuclear modification of single inclusive full jet spectra, the momentum imbalance of photon-jet and dijet pairs, and the jet shape function (at partonic level) in Pb+Pb collisions at 2.76 A TeV. The roles of various jet-medium interaction mechanisms on the full jet modification are studied. We find that the nuclear modification of jet shape is sensitive to the interplay of different interaction mechanisms as well as the energies of the full jets.
Liu, Fu-Hu; Lacey, Roy A
2015-01-01
Experimental results of the rapidity distributions of negatively charged pions produced in proton-proton (p-p) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parameter c^2_s is then extracted from the width of rapidity distribution. There is a knee point appearing at about 40A GeV/c (or 8.8 GeV) in the dependence of c^2_s on incident beam momentum (or center-of-mass energy). This knee point can be possibly regarded as the onset of deconfinement of the quarks and gluons in proton-proton collisions, and the critical point of phase transition from hadronic matter to quark-gluon plasma (QGP) in nucleus-nucleus collisions. It is possible that the quark deconfinement and QGP phase transition happen initially in collisions at 8.8 GeV.
Phase Space and Dynamical Fluctuations of Kaon--to--Pion Ratios
Tawfik, A
2010-01-01
The dynamical fluctuations of kaon--to--pion ratios have been studied over a wide range of center--of--mass energies $\\sqrt{s}$. Based on changing phase space volume which apparently is the consequence of phase transition from hadrons to quark--gluon plasma at large $\\sqrt{s}$, single--particle distribution function $f$ is assumed to be rather modified. Varying $f$ and phase space volume are implemented in the grand--canonical partition function, especially at large $\\sqrt{s}$, so that hadron resonance gas model, when taking into account the experimental acceptance and quark phase space occupation factor, turns to be able to reproduce the dynamical fluctuations over the entire range of $\\sqrt{s}$.
Andronic, A; Braun-Munzinger, P; Cleymans, J; Fukushima, K; McLerran, L D; Oeschler, H; Pisarski, R D; Redlich, K; Sasaki, C; Satz, H; Stachel, J
2009-01-01
We argue that features of hadron production in relativistic nuclear collisions, mainly at CERN-SPS energies, may be explained by the existence of three forms of matter: Hadronic Matter, Quarkyonic Matter, and a Quark-Gluon Plasma. We suggest that these meet at a triple point in the QCD phase diagram. Some of the features explained, both qualitatively and semi-quantitatively, include the curve for the decoupling of chemical equilibrium, along with the non-monotonic behavior of strange particle multiplicity ratios at center of mass energies near 10 GeV. If the transition(s) between the three phases are merely crossover(s), the triple point is only approximate.
Strangeness enhancement - a potential signature for QGP phase
Tiwari, V. K.; Singh, C. P.
1997-09-01
Strangeness enhancement has always been considered as a potential signature for deconfining as well as chiral symmetry restoring quark-hadron phase transition. We obtain the ratios Λ¯/Λ, Ξ¯/Ξ and K+/K- from a quark-gluon plasma (QGP) using a modified equation of state (EOS). Similarly these ratios are also obtained from a hadron gas (HG) by using a thermodynamically consistent equation of state (EOS) which incorporates the finite size, hard-core repulsive interactions among baryons as an excluded volume effect. We then suggest that the variations of these ratios either with the energy density or with baryon density can serve as a potential signature for detecting a QGP formation in the ultra-relativistic heavy-ion collisions.
Energy Technology Data Exchange (ETDEWEB)
Gelis, Francois [Savoie Univ., 73 - Chambery (France)
1998-12-01
The general framework of this work is thermal field theory, and more precisely the perturbative calculation of thermal Green`s functions. In a first part, I consider the problems closely related to the formalism itself. After two introductory chapters devoted to set up the framework and the notations used afterwards, a chapter is dedicated to a clarification of certain aspects of the justification of the Feynman rules of the real time formalism. Then, I consider in the chapter 4 the problem of cutting rules in the real time formalisms. In particular, after solving a controversy on this subject, I generalize these cutting rules to the `retarded-advanced` version of this formalism. Finally, the last problem considered in this part is that of the pion decay into two photons in a thermal bath. I show that the discrepancies found in the literature are due to peculiarities of the analytical properties of the thermal Green`s functions. The second part deals with the calculations of the photons or dilepton (virtual photon) production rate by a quark gluon plasma. The framework of this study is the effective theory based on the resummation of hard thermal loops. The first aspects of this study is related to the production of virtual photons, where we show that important contributions arise at two loops, completing the result already known at one loop. In the case of real photon production, we show that extremely strong collinear singularities make two loop contributions dominant compared to one loop ones. In both cases, the importance of two loop contributions can be interpreted as weaknesses of the hard thermal loop approximation. (author) 366 refs., 109 figs.
QCD Phase Transition in a new Hybrid Model Formulation
Srivastava, P K
2013-01-01
Search of a proper and realistic equations of state (EOS) for strongly interacting matter used in the study of QCD phase diagram still appears as a challenging task. Recently, we have constructed a hybrid model description for the quark gluon plasma (QGP) as well as hadron gas (HG) phases where we use a new excluded-volume model for HG and a thermodynamically-consistent quasiparticle model for the QGP phase. We attempt to use them to get a QCD phase boundary and a critical point. We test our hybrid model by reproducing the entire lattice QCD data for strongly interacting matter at zero baryon chemical potential ($\\mu_{B}$)and predict the results at finite $\\mu_{B}$ and $T$.
Isotropization of the quark gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Epelbaum, T.; Gelis, F.
2014-06-15
We report here recent analytical and numerical work on the theoretical treatment of the early stages of heavy ion collisions, that amounts to solving the classical Yang–Mills equations with fluctuating initial conditions. Our numerical simulations suggest a fast isotropization of the pressure tensor of the system. This trend appears already for small values of the coupling constant α{sub s}. In addition, the system exhibits an anomalously small shear viscosity.
Turbulent thermalization of the Quark Gluon Plasma
Berges, J; Schlichting, S; Venugopalan, R
2013-01-01
Classical-statistical lattice gauge theory simulations are employed to demonstrate the existence of a nonthermal fixed point in the space-time evolution of heavy ion collisions at ultrarelativistic energies. After an initial transient regime dominated by plasma instabilities and free streaming, the ensuing overpopulated non-Abelian plasma exhibits the universal self-similar dynamics characteristic of wave turbulence observed in a large variety of physical systems across different energy scales.
Evolution to the Quark-Gluon Plasma
Fukushima, Kenji
2016-01-01
Theoretical studies on the early-time dynamics in the ultra-relativistic heavy-ion collisions are reviewed including pedagogical introductions on the initial condition with small-x gluons treated as a color glass condensate, the bottom-up thermalization scenario, plasma/glasma instabilities, basics of some formulations such as the kinetic equations and the classical statistical simulation. More detailed discussions follow to make an overview of recent developments on the fast isotropization, the onset of hydrodynamics, and the transient behavior of momentum spectral cascades.
Working group report: Quark gluon plasma
Indian Academy of Sciences (India)
Pradip Roy; Bedangadas Mohanty; A P Balchandran; A Bhattacharyya; A K Chaudhuri; S Datta; S Digal; F Flueret; S Gupta; P Jaikumar; S H Lee; N Mathur; A Mishra; A P Mishra; H Mishra; B Mohanty; P Roy; P S Somia; A M Srivastava
2009-01-01
The 10th Workshop on High Energy Physics Phenomenology (WHEPP-10) was held at the Institute of Mathematical Sciences, Chennai during January 2–13, 2008. One of our working grops (WG) is QCD and QGP. The discussions of QGP WG include matter at high density, lattice QCD, charmonium states in QGP, viscous hydrodynamics and jet quenching, colour factor in heavy ion collisions and RHIC results on photons, dileptons and heavy quark. There were two plenary talks and several working group talks with intense discussions regarding the future activities that are going to be persued.
New Basic Physics Derived from Laser Plasma Interaction (lirpp Vol. 10)
Hora, Heinrich
2016-10-01
The following sections are included: * INTRODUCTION * VARIOUS PHENOMENA * COMPLETION OF THE EQUATION OF MOTION BY NONLINEAR FORCES * NONLINEAR PRINCIPLE * CONTAINMENT FORCE OF HADRONS IN NUCLEI AND PHASE TRANSITION INTO QUARK GLUON PLASMA * Acknowledgements * References
Parity doubling of nucleons and Delta baryons across the deconfinement phase transition
Aarts, Gert; De Boni, Davide; Hands, Simon; Jaeger, Benjamin; Praki, Chrisanthi; Skullerud, Jon-Ivar
2016-01-01
At zero temperature the negative-parity ground states of the nucleon and delta baryons are non-degenerate with the positive-parity partners due to spontaneous breaking of chiral symmetry. However, chiral symmetry is expected to be restored at sufficiently high temperature, in particular when going from the hadronic to the quark-gluon plasma (QGP) phase. This would imply that channels with opposite parity become degenerate. We study the nucleon (spin $1/2$) and $\\Delta$ (spin $3/2$) baryons in both parity sectors using lattice QCD. The range of temperatures spans both the hadronic and QGP phases. Using the FASTSUM anisotropic $N_f = 2 + 1$ ensembles, we analyze the correlation functions and the spectral functions using respectively exponential fits and the Maximum Entropy Method. We find clear evidence of in-medium effects in the hadronic phase, especially for the negative-parity ground state, and of parity doubling in the QGP phase.
Confinement in Polyakov gauge and the QCD phase diagram
Energy Technology Data Exchange (ETDEWEB)
Marhauser, Marc Florian
2009-10-14
We investigate Quantum Chromodynamics (QCD) in the framework of the functional renormalisation group (fRG). Thereby describing the phase transition from the phase with confined quarks into the quark-gluon-plasma phase. We focus on a physical gauge in which the mechanism driving the phase transition is discernible. We find results compatible with lattice QCD data, as well as with functional methods applied in different gauges. The phase transition is of the expected order and we computed critical exponents. Extensions of the model are discussed. When investigating the QCD phase diagram, we compute the effects of dynamical quarks at finite density on the running of the gauge coupling. Additionally, we calculate how these affect the deconfinement phase transition, also, dynamical quarks allow for the inclusion of a finite chemical potential. Concluding the investigation of the phase diagram, we establish a relation between confinement and chiral symmetry breaking, which is tied to the dynamical generation of hadron masses. In the investigations, we often encounter scale dependent fields. We investigate a footing on which these can be dealt with in a uniform way. (orig.)
Clustering of Color Sources and the Equation of State of the QGP
Directory of Open Access Journals (Sweden)
Srivastava Brijesh K
2014-04-01
Full Text Available Possible phase transition of strongly interacting matter from hadron to a quark-gluon plasma state have in the past received considerable interest. It has been suggested that this problem might be treated by percolation theory. The clustering of color sources with percolation (CSPM is used to determine the equation of state (EOS and the transport coefficient of the Quark-Gluon Plasma (QGP produced in central A-A collisions at RHIC and LHC energies.
Clustering of Color Sources and the Equation of State of the QGP
Srivastava, Brijesh K.
2014-04-01
Possible phase transition of strongly interacting matter from hadron to a quark-gluon plasma state have in the past received considerable interest. It has been suggested that this problem might be treated by percolation theory. The clustering of color sources with percolation (CSPM) is used to determine the equation of state (EOS) and the transport coefficient of the Quark-Gluon Plasma (QGP) produced in central A-A collisions at RHIC and LHC energies.
Hybrid model for QCD deconfining phase boundary
Srivastava, P. K.; Singh, C. P.
2012-06-01
Intensive search for a proper and realistic equations of state (EOS) is still continued for studying the phase diagram existing between quark gluon plasma (QGP) and hadron gas (HG) phases. Lattice calculations provide such EOS for the strongly interacting matter at finite temperature (T) and vanishing baryon chemical potential (μB). These calculations are of limited use at finite μB due to the appearance of notorious sign problem. In the recent past, we had constructed a hybrid model description for the QGP as well as HG phases where we make use of a new excluded-volume model for HG and a thermodynamically-consistent quasiparticle model for the QGP phase and used them further to get QCD phase boundary and a critical point. Since then many lattice calculations have appeared showing various thermal and transport properties of QCD matter at finite T and μB=0. We test our hybrid model by reproducing the entire data for strongly interacting matter and predict our results at finite μB so that they can be tested in future. Finally we demonstrate the utility of the model in fixing the precise location, the order of the phase transition and the nature of CP existing on the QCD phase diagram. We thus emphasize the suitability of the hybrid model as formulated here in providing a realistic EOS for the strongly interacting matter.
Solé, Ricard V
2011-01-01
Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation o
Critical Point on the QCD Deconfining Phase Boundary
Srivastava, P K
2012-01-01
Ambiguities regarding the physics and the existence of the critical point (CP) on the QCD phase boundary still exist and the mist regarding the conjectured QCD phase boundary has not yet cleared. In this paper we extend our earlier study where we constructed a deconfining phase boundary using Gibbs' equilibrium conditions after using a quasiparticle equation of state (EOS) for quark gluon plasma (QGP) and an excluded volume EOS for the hadron gas (HG) and find the presence of a critical point on this phase boundary where the first order phase transition terminates. In this paper, we plot the difference in the normalized entropy density ($s/T^{3}$) between HG and QGP phases along the deconfining phase boundary and find that it vanishes at CP. Further we have shown the variation of the square of speed of sound ($c_{s}^{2}$) for the HG and QGP separately and find that the difference ($\\Delta c_{s}^{2}$) between them along the deconfining phase boundary again vanishes at the CP of the boundary. We also plot the v...
Baryon number transfer could delay Quark-Hadron transition in cosmology
Bonometto, Silvio A
2016-01-01
In the early Universe, s.i. matter was a quark-gluon plasma. Both lattice computations and heavy ion collision experiments however tell us that, in the absence of chemical potentials, no plasma survives at $T <\\sim 150\\, $MeV. The cosmological QH transition, however, seems to have been a crossover; cosmological consequences envisaged when it was believed to be a phase transition no longer hold. In this paper we discuss whether even a crossover transition can leave an imprint that cosmological observations can seek or, viceversa, there are questions cosmology should still ask QCD specialists. In this context, we outline, first of all, that it is still unclear how baryons (not hadrons) could form at the cosmological transition. A critical role should be played by diquark states, whose abundance in the early plasma needs to be accurately evaluated. We estimate that, if the number of quarks belonging to a diquark state, at the eve of the cosmological transition, is $<\\sim 1:10^6$, its dynamics could be modi...
New signals of quark-gluon-hadron mixed phase formation
Energy Technology Data Exchange (ETDEWEB)
Bugaev, K.A.; Sagun, V.V.; Ivanytskyi, A.I.; Zinovjev, G.M. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Oliinychenko, D.R. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Goethe University, FIAS, Frankfurt am Main (Germany); Ilgenfritz, E.M. [JINR, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Nikonov, E.G. [JINR, Laboratory for Information Technologies, Dubna (Russian Federation); Taranenko, A.V. [Moscow Engineering Physics Institute, National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation)
2016-08-15
Here we present several remarkable irregularities at chemical freeze-out which are found using an advanced version of the hadron resonance gas model. The most prominent of them are the sharp peak of the trace anomaly existing at chemical freeze-out at the center-of-mass energy 4.9 GeV and two sets of highly correlated quasi-plateaus in the collision energy dependence of the entropy per baryon, total pion number per baryon, and thermal pion number per baryon which we found at the center-of-mass energies 3.8-4.9 GeV and 7.6-10 GeV. The low-energy set of quasi-plateaus was predicted a long time ago. On the basis of the generalized shock-adiabat model we demonstrate that the low-energy correlated quasi-plateaus give evidence for the anomalous thermodynamic properties inside the quark-gluon-hadron mixed phase. It is also shown that the trace anomaly sharp peak at chemical freeze-out corresponds to the trace anomaly peak at the boundary between the mixed phase and quark gluon plasma. We argue that the high-energy correlated quasi-plateaus may correspond to a second phase transition and discuss its possible origin and location. Besides we suggest two new observables which may serve as clear signals of these phase transformations. (orig.)
Gauge/gravity duality. From quantum phase transitions towards out-of-equilibrium physics
Energy Technology Data Exchange (ETDEWEB)
Ngo Thanh, Hai
2011-05-02
In this dissertation we use gauge/gravity duality to investigate various phenomena of strongly coupled field theories. Of special interest are quantum phase transitions, quantum critical points, transport phenomena of charges and the thermalization process of strongly coupled medium. The systems studied in this thesis might be used as models for describing condensed matter physics in a superfluid phase near the quantum critical point and the physics of quark-gluon plasma (QGP), a deconfinement phase of QCD, which has been recently created at the Relativistic Heavy Ion Collider (RHIC). Moreover, we follow the line of considering different gravity setups whose dual field descriptions show interesting phenomena of systems in thermal equilibrium, slightly out-of-equilibrium and far-from-equilibrium. We first focus on systems in equilibrium and construct holographic superfluids at finite baryon and isospin charge densities. For that we use two different approaches, the bottom-up with an U(2) Einstein-Yang-Mills theory with back-reaction and the top-down approach with a D3/D7 brane setup with two coincident D7-brane probes. In both cases we observe phase transitions from a normal to a superfluid phase at finite and also at zero temperature. In our setup, the gravity duals of superfluids are Anti-de Sitter black holes which develop vector-hair. Studying the order of phase transitions at zero temperature, in the D3/D7 brane setup we always find a second order phase transition, while in the Einstein-Yang-Mills theory, depending on the strength of the back-reaction, we obtain a continuous or first order transition. We then move to systems which are slightly out-of-equilibrium. Using the D3/D7 brane setup with N{sub c} coincident D3-branes and N{sub f} coincident D7-brane probes, we compute transport coefficients associated with massive N=2 supersymmetric hypermultiplet fields propagating through an N=4 SU(N{sub c}) super Yang-Mills plasma in the limit of N{sub f}<
Gitterman, Moshe
2014-09-01
In discussing phase transitions, the first thing that we have to do is to define a phase. This is a concept from thermodynamics and statistical mechanics, where a phase is defined as a homogeneous system. As a simple example, let us consider instant coffee. This consists of coffee powder dissolved in water, and after stirring it we have a homogeneous mixture, i.e., a single phase. If we add to a cup of coffee a spoonful of sugar and stir it well, we still have a single phase -- sweet coffee. However, if we add ten spoonfuls of sugar, then the contents of the cup will no longer be homogeneous, but rather a mixture of two homogeneous systems or phases, sweet liquid coffee on top and coffee-flavored wet sugar at the bottom...
Energy Technology Data Exchange (ETDEWEB)
KARSCH, F.
2006-03-26
At high temperatures or densities matter formed by strongly interacting elementary particles (hadronic matter) is expected to undergo a transition to a new form of matter--the quark gluon plasma--in which elementary particles (quarks and gluons) are no longer confined inside hadrons but are free to propagate in a thermal medium much larger in extent than the typical size of a hadron. The transition to this new form of matter as well as properties of the plasma phase are studied in large scale numerical calculations based on the theory of strong interactions--Quantum Chromo Dynamics (QCD). Experimentally properties of hot and dense elementary particle matter are studied in relativistic heavy ion collisions such as those currently performed at the relativistic heavy ion collider (RHIC) at BNL. We review here recent results from studies of thermodynamic properties of strongly interacting elementary particle matter performed on Teraflops-Computer. We present results on the QCD equation of state and discuss the status of studies of the phase diagram at non-vanishing baryon number density.
Entropy production for an interacting quark-gluon plasma
Mattiello, Stefano
2011-01-01
We investigate the entropy production within dissipative hydrodynamics in the Israel-Stewart (IS) and Navier-Stokes theory (NS) for relativistic heavy ion physics applications. In particular we focus on the initial condition in a 0+1D Bjorken scenario, appropriate for the early longitudinal expansion stage of the collision. Going beyond the standard simplification of a massless ideal gas we consider a realistic equation of state consistently derived within a virial expansion. The EoS used is well in line with recent three-flavor QCD lattice data for the pressure, speed of sound, and interaction measure at nonzero temperature and vanishing chemical potential ($\\mu_{\\rm q} = 0$). The shear viscosity has been consistently calculated within this formalism using a kinetic approach in the ultra-relativistic regime with an explicit and systematic evaluation of the transport cross section as function of temperature. We investigate the influence of the viscosity and the initial condition, i.e. formation time, initial ...
Viscous quark-gluon plasma in the early universe
Energy Technology Data Exchange (ETDEWEB)
Tawfik, A.; Wahba, M. [Egyptian Center for Theoretical Physics (ECTP), MTI University, Al-Mukkatam, Cairo 11212 (Egypt); Mansour, H. [Department of Physics, Cairo University, Giza 12613 (Egypt); Harko, T. [Department of Physics and Center for Theoretical and Computational Physics, The University of Hong Kong, Pok Fu Lam Road (China)
2011-03-15
In the present work a study is given for the evolution of a flat, isotropic and homogeneous Universe, which is filled with a causal bulk viscous cosmological fluid. We describe the viscous properties by an ultra-relativistic equation of state, and bulk viscosity coefficient obtained from recent lattice QCD calculations. The basic equation for the Hubble parameter is derived by using the energy equation obtained from the assumption of the covariant conservation of the energy-momentum tensor of the matter in the Universe. By assuming a power law dependence of the bulk viscosity coefficient, temperature and relaxation time on the energy density, we derive the evolution equation for the Hubble function. By using the equations of state from recent lattice QCD simulations and heavy-ion collisions we obtain an approximate solution of the field equations. In this treatment for the viscous cosmology, no evidence for singularity is observed. For example, both the Hubble parameter and the scale factor are finite at t=0, where t is the comoving time. Furthermore, their time evolution essentially differs from the one associated with non-viscous and ideal gas. Also it is noticed that the thermodynamic quantities, like temperature, energy density and bulk pressure remain finite. Particular solutions are also considered in order to prove that the free parameter in this model does qualitatively influence the final results. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Viscous Quark-Gluon Plasma in the Early Universe
Tawfik, A; Mansour, H; Harko, T
2010-01-01
We consider the evolution of a flat, isotropic and homogeneous Friedmann-Robertson-Walker Universe, filled with a causal bulk viscous cosmological fluid, that can be characterized by an ultra-relativistic equation of state and bulk viscosity coefficient obtained from recent lattice QCD calculations. The basic equation for the Hubble parameter is derived under the assumption that the total energy in the Universe is conserved. By assuming a power law dependence of bulk viscosity coefficient, temperature and relaxation time on energy density, an approximate solution of the field equations has been obtained, in which we utilized equations of state from recent lattice QCD simulations QCD and heavy-ion collisions to derive an evolution equation. In this treatment for the viscous cosmology, we found no evidence for singularity. For example, both Hubble parameter and scale factor are finite at $t=0$, $t$ is the comoving time. Furthermore, their time evolution essentially differs from the one associated with non-visco...
The Strongly Interacting Quark Gluon Plasma at RHIC and LHC
Directory of Open Access Journals (Sweden)
Tserruya Itzhak
2014-04-01
Full Text Available The study of heavy-ion collisions has currently unprecedented opportunities with two first class facilities, the Relativistic Heavy Ion Collider (RHIC at BNL and the Large Hadron Collider (LHC at CERN, and five large experiments ALICE, ATLAS, CMS, PHENIX and STAR producing a wealth of high quality data. Selected results recently obtained are presented on the study of flow, energy loss and direct photons.
Nonperturbative equation of state of quark gluon plasma: Applications
Komarov, E. V.; Simonov, Yu. A.
2008-05-01
The vacuum-driven nonperturbative factors Li for quark and gluon Green's functions are shown to define the nonperturbative dynamics of QGP in the leading approximation. EoS obtained recently in the framework of this approach is compared in detail with known lattice data for μ = 0 including P/ T4, ɛ/ T4, {ɛ-3P}/{T4}. The basic role in the dynamics at T ≲ 3 Tc is played by the factors Li which are approximately equal to the modulus of Polyakov line for quark Lfund and gluon Ladj. The properties of Li are derived from field correlators and compared to lattice data, in particular the Casimir scaling property Ladj=(Lfund) follows in the Gaussian approximation valid for small vacuum correlation lengths. Resulting curves for P/ T4, ɛ/ T4, {ɛ-3P}/{T4} are in a reasonable agreement with lattice data, the remaining difference points out to an effective attraction among QGP constituents.
Nonperturbative equation of state of quark-gluon plasma. Applications
Komarov, E V
2007-01-01
The vacuum-driven nonperturbative factors $L_i$ for quark and gluon Green's functions are shown to define the nonperturbative dynamics of QGP in the leading approximation. EoS obtained recently in the framework of this approach is compared in detail with known lattice data for $\\mu=0$ including $P/T^4$, $\\epsilon/T^4$, $\\frac{\\epsilon-3P}{T^4}$. The basic role in the dynamics at $T\\la 3T_c$ is played by the factors $L_i$ which are approximately equal to the modulus of Polyakov line for quark $L_{fund}$ and gluon $L_{adj}$. The properties of $L_i$ are derived from field correlators and compared to lattice data, in particular the Casimir scaling property $L_{adj} =(L_{fund})^{\\frac{C_2(adj)}{C_2(fund)}}$ follows in the Gaussian approximation valid for small vacuum correlation lengths. Resulting curves for $P/T^4$, $\\epsilon/T^4$, $\\frac{\\epsilon-3P}{T^4}$ are in a reasonable agreement with lattice data, the remaining difference points out to an effective attraction among QGP constituents.
Gravitational collisions and the quark-gluon plasma
van der Schee, Wilke
2014-01-01
This thesis addresses the thermalisation of heavy-ion collisions within the context of the AdS/CFT duality. The first part clarifies the numerical set-up and studies the relaxation of far-from-equilibrium modes in homogeneous systems. Less trivially we then study colliding shock waves and uncover a transparent regime where the strongly coupled shocks initially pass right through each other. Furthermore, in this regime the later plasma relaxation is insensitive to the longitudinal profile of the shock, implying in particular a universal rapidity shape at strong coupling and high collision energies. Lastly, we study radial expansion in a boost-invariant set-up, allowing us to find good agreement with head-on collisions performed at the LHC accelerator. As a secondary goal of this thesis, a special effort is made to clearly expose numerical computations by providing commented Mathematica notebooks for most calculations presented. Furthermore, we provide interpolating functions of the geometries computed, which c...
Holographic Duals of Quark Gluon Plasmas with Unquenched Flavors
Institute of Scientific and Technical Information of China (English)
Francesco Bigazzi; Aldo Cotrone; Javier Mas; Daniel Mayerson; Javier Tarrio
2012-01-01
We review the construction of gravitational solutions holographically dual to N = 1 quiver gauge theories with dynamical flavor multiplets. We focus on the D3-D7 construction and consider the finite temperature, finite quark chemical potential case where there is a charged black hole in the dual solution. Discussed physical outputs of the model include its thermodynamics （with susceptibilities） and general hydrodynamic properties.
2015-01-01
Follow Italian @ALICEexperiment physicist Chiara Zampolli from INFN Bologna, Italy, as she shares her thoughts about the new physics frontiers opening up when the LHC begins collisions at the higher energy of #13TeV. Each week a new video will be uploaded to https://www.youtube.com/playlist?list... allowing you to follow physicists from @ATLASexperiment @ALICEexperiment @CMSexperiment or @LHCbExperiment as the search the new frontiers in physics. Read more about these new frontiers in physics: http://cern.ch/go/x8VH
Thermal charm and charmonium production in quark gluon plasma
Directory of Open Access Journals (Sweden)
Kai Zhou
2016-07-01
Full Text Available We study the effect of thermal charm production on charmonium regeneration in high energy nuclear collisions. By solving the kinetic equations for charm quark and charmonium distributions in Pb+Pb collisions, we calculate the global and differential nuclear modification factors RAA(Npart and RAA(pt for J/ψ s. Due to the thermal charm production in hot medium, the charmonium production source changes from the initially created charm quarks at SPS, RHIC and LHC to the thermally produced charm quarks at Future Circular Collider (FCC, and the J/ψ suppression (RAA1 at FCC at low transverse momentum.
Universal limiting pressure for a three-flavor color superconducting PNJL model phase diagram
Ayriyan, A; Blaschke, D; Lastowiecki, R
2016-01-01
The phase diagram of a three-flavor Polyakov-loop Nambu-Jona-Lasinio model is analyzed for the case of isospin symmetric matter with color superconducting phases. The coexistence of chiral symmetry breaking and two-flavor color superconductivity (2SC phase) and a thermodynamic instability due to the implementation of a color neutrality constraint is observed. It is suggested to use a universal hadronization pressure to estimate the phase border between hadronic and quark-gluon plasma phases. Trajectories of constant entropy per baryon are analyzed for conditions appropriate for heavy-ion collisions in the NICA-FAIR energy range.
Energy Technology Data Exchange (ETDEWEB)
Rakotozafindrabe, A
2007-05-15
This work deals with the measurement of the production of J/{psi} in Cu + Cu collisions at 200 GeV per nucleon pair via their decay channel into 2 muons. The experimental data used is that collected during the 2005 campaign at the RHIC. In the first chapter, we present the theoretical context of the study of quark-gluon plasmas (QGP) and its production in relativistic heavy ion collisions. The second chapter deals with the production of J/{psi} in proton-proton collisions and in case of light ion collisions where QGP can not be produced. The experimental setting is presented in the third chapter, particularly the muon spectrometer and the detectors whose purpose is to measure collision centrality. Data analysis concerning the extraction of the signal and the reconstruction of data is described in the fourth chapter. The method that has enabled us to extract the production of the J/{psi} as well as its uncertainties is detailed in the fifth chapter.
Entropy production in the early-cosmology pionic phase
Dobado, Antonio; Rodriguez-Fernandez, David
2015-01-01
We point out that in the early universe, for temperatures in the approximate interval 175-80 MeV (after the quark-gluon plasma), pions carried a large share of the entropy and supported the largest inhomogeneities. Thus, we examine the production of entropy in a pion gas, particularizing to inhomogeneities of the temperature, for which we benefit from the known thermal conductivity. We finally put that entropy produced in relaxing such thermal inhomogeneities in the broad context of this relatively unexplored phase of early-universe cosmology.
Institute of Scientific and Technical Information of China (English)
管娜娜
2016-01-01
Dileptons have large mean free paths due to their small cross sections for electromagnetic interaction in plasma. Therefore they are considered to be an important probe for the formation and evolution of the quark matter. In this work, we calculate the dilepton production of quark-gluon plasma (QGP) produced in Au197+Au197 central collisions at relativistic heavy ion collider (RHIC) energy based on the evolution model of a chemically equilibrating viscous QGP. The evolution of the QGP system is described by a set of coupled relaxation equations containing the master equations of partons, the equation of baryon number conservation and equation of energy-momentum conservation. Solving the set of evolution equations, one can obtain the evolution of temperature T , quark chemical potential µq, fugacitiesλq for quarks andλg for gluons. To discuss the shear viscosity of QGP, the contributions of the elastic scattering of quarks q¯q−→q¯q and gluons gg→gg, as well as the inelastic scattering process of gluons gg↔ggg are included. Based on the evolution model including the viscosity, we perform a complete calculation of the dilepton production, including the processes of quark-antiquark annihilation q¯q→l¯l, next-order annihilation q¯q→gl¯l, Compton-like scattering qg → ql¯l, ¯qg → ¯ql¯l, multiple scattering of quarks, as well as gluon fusion gg → c¯c, annihilation q¯q→c¯c. It is found that the spectra from the quark-antiquark annihilations q¯q→l¯l and q¯q→gl¯l are dominated. The contributions from multiple scattering cannot be neglected. We also find that the dilepton yields remarkably decrease with considering an additional gluon inelastic process in the calculation compared with the results with considering only elastic scatterings of quarks and gluons. This indicates that the evolution of QGP system is accelerated and the evolution time is shortened by the inelastic scatterings of gluons.%双轻子是研究夸克物质的形
Parity doubling of nucleons, Delta and Omega baryons across the deconfinement phase transition
Aarts, Gert; De Boni, Davide; Hands, Simon; Jaeger, Benjamin; Praki, Chrisanthi; Skullerud, Jon-Ivar
2016-01-01
In this work we analyse positive- and negative-parity channels for the nucleon (spin $1/2$ octet), $\\Delta$ and $\\Omega$ baryons (spin $3/2$ decuplet) using lattice QCD. In Nature, at zero temperature, chiral symmetry is spontaneously broken, causing positive- and negative-parity ground states to have different masses. However, chiral symmetry is expected to be restored (for massless quarks) around the crossover temperature, implying that the two opposite parity channels should become degenerate. Here we study what happens in a temperature range which includes both the hadronic and the quark gluon plasma (QGP) phase. By analysing the correlation and spectral functions via exponential fits and the Maximum Entropy Method respectively, we have found parity doubling for the nucleon and $\\Delta$ baryon channels in the QGP phase. For the $\\Omega$ baryon we see a clear signal of parity doubling at the crossover temperature, which is however not complete, due to the nonzero strange quark mass. Moreover, in-medium eff...
Energy Technology Data Exchange (ETDEWEB)
Ladrem, M.; Ait-El-Djoudi, A. [Ecole Normale Superieure-Kouba, Laboratoire de Physique des Particules et Physique Statistique, B.P. 92, Vieux-Kouba, Algiers (Algeria)
2005-10-01
We study the finite-size effects for the thermal quantum chromodynamics (QCD) deconfinement phase transition, and use a numerical finite-size scaling analysis to extract the scaling exponents characterizing its scaling behavior when approaching the thermodynamic limit (V{yields}{infinity}). For this, we use a simple model of coexistence of hadronic gas and color-singlet quark gluon plasma (QGP) phases in a finite volume. The color-singlet partition function of the QGP cannot be exactly calculated and is usually derived within the saddle-point approximation. When we try to do calculations with such an approximate color-singlet partition function, a problem arises in the limit of small temperatures and/or volumes VT{sup 3}<<1, requiring additional approximations if we want to carry out calculations. We propose in this work a method for an accurate calculation of any quantity of the finite system, without any approximation. By probing the behavior of some useful thermodynamic response functions on the whole range of temperature, it turns out that, in a finite-size system, all singularities in the thermodynamic limit are smeared out and the transition point is shifted away. A numerical finite-size scaling (FSS) analysis of the obtained data allows us to determine the scaling exponents of the QCD deconfinement phase transition. Our results expressing the equality between their values and the space dimensionality is a consequence of the singularity characterizing a first-order phase transition and agree very well with the predictions of other FSS theoretical approaches to a first-order phase transition and with the results of calculations using Monte Carlo methods in both lattice QCD and statistical physics models. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Pillot, Ph
2005-05-15
The study of heavy quark production such as J/{psi} (cc-bar resonance) and {upsilon} (bb-bar resonance) in heavy ion collisions at high incident energies has been proposed as a tool to investigate the formation of a Quark Gluon Plasma. Experimentally, these resonances can be detected through their decay channel into a muon pair, using a muon spectrometer. The optimal resolution of a muon spectrometer cannot be reached unless the position of the different tracking detectors are accurately known. In the first part of the work reported in this thesis are presented the design and performances of the Geometry Monitoring System of the ALICE experiment's muon spectrometer at LHC. This system, which is composed of several hundreds of RASNIK derived optical devices, allows to measure displacements and deformations of the chambers with a precision better than a hundred of microns. Thanks to its muon spectrometer associated with a vertex telescope, the NA60 experiment studies the dimuon production in nucleus-nucleus collisions at CERN SPS. The second part of the work reported in this thesis is related to the analysis of the data collected in indium-indium collisions at 158 GeV/c/nucleon. More specifically, the J/{psi} production together with its transverse momentum and transverse mass distributions are studied as a function of the centrality of the collision. The different results arising from our analysis are then compared to those obtained previously by NA38 and NA50, allowing a better understanding of the ultrarelativistic heavy ion collisions. (author)
Institute of Scientific and Technical Information of China (English)
2001-01-01
One of the aims to research relativistic heavy-ion collisions is to explore the probability of quark-gluon plasma phase transition from normal nuclear matter. Hadron and string cascade model (JPCIAE) ,based on the hypothesis without introducing the quark-gluon plasma (QGP), is employed to study the direct photon and π 0 transverse momentum distributions for central 208Pb+208Pb collisions at 158 AGeV/c; The theoretical results of transverse momentum distribution for both the direct photon and the π0 particle are lower than the data of WA98 experiment. Having considered the fact that the
Hadronic resonance production in d+Au collisions at √sNN = 200 GeV at RHIC
van Leeuwen, M.; Abelev, B.I.; Bai, Y.; Benedosso, F.; Botje, M.A.J.; Braidot, E; Mischke, A.; Peitzmann, T.; Russcher, M.J.; Snellings, R.J.M.
2008-01-01
Quantum chromodynamics (QCD) predicts that hadronic matter at high temperatures and/or high densities undergoes a phase transition to a system of deconfined partonic matter, the Quark Gluon Plasma (QGP) [1]. Matter under such extreme conditions can be studied in the laboratory by colliding nuclei at
Modelling and measurement of jet quenching in relativistic heavy-ion collisions at the LHC
Verweij, M.
2013-01-01
In relativistic collisions between nuclei, the creation of a strongly interacting medium, called the Quark Gluon Plasma (QGP), is expected. It is expected that such a medium also existed in the early universe just after the Big Bang. The phase transition of interest is where the dense medium of free
2003-01-01
Fitted with new state-of-the-art silicon detectors, NA60 is prepared to study the phase transition from confined hadronic matter to a deconfined (free) quark-gluon plasma, a state of matter which probably existed an instant after the Big Bang.
Energy Technology Data Exchange (ETDEWEB)
Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)
1996-11-01
Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.
Phase transitions modern applications
Gitterman, Moshe
2014-01-01
This book provides a comprehensive review of the theory of phase transitions and its modern applications, based on the five pillars of the modern theory of phase transitions i.e. the Ising model, mean field, scaling, renormalization group and universality. This expanded second edition includes, along with a description of vortices and high temperature superconductivity, a discussion of phase transitions in chemical reaction and moving systems. The book covers a close connection between phase transitions and small world phenomena as well as scale-free systems such as the stock market and the Internet. Readership: Scientists working in different fields of physics, chemistry, biology and economics as well as teaching material for undergraduate and graduate courses.
Institute of Scientific and Technical Information of China (English)
许可; 李未
1999-01-01
Phase transition is an important feature of SAT problem. For random k-SAT model, it is proved that as r（ratio of clauses to variables） increases, the structure of solutions will undergo a sudden change like satisfiability phase transition when r reaches a threshold point (r=rcr). This phenomenon shows that the satisfying truth assignments suddenly shift from being relatively different from each other to being very similar to each other.##属性不符
Indian Academy of Sciences (India)
Dinesh Kumar Srivastava
2001-08-01
The production of single photons in Pb+Pb collisions at the CERN SPS as measured by the WA98 experiment is analysed. A quark gluon plasma is assumed to be formed initially, which expands, cools, hadronizes, and undergoes freeze-out. A rich hadronic equation of state is used and the transverse expansion of the interacting system is taken into account. The recent estimates of photon production in quark-matter (at two loop level) along with the dominant reactions in the hadronic matter leading to photons are used. About half of the radiated photons are seen to have a thermal origin. The same treatment and the initial conditions provide a very good description to hadronic spectra measured by several groups and the intermediate mass dileptons measured by the NA50 experiment, lending a strong support to the conclusion that quark gluon plasma has been formed in these collisions. Predictions for RHIC and LHC energies are also given.
Kopaev, YuV
1992-01-01
Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle ele
Photoinduced phase transitions
Nasu, K
2004-01-01
A new class of insulating solids was recently discovered. Whenirradiated by a few visible photons, these solids give rise to amacroscopic excited domain that has new structural and electronicorders quite different from the starting ground state. This occurrenceis called "photoinduced phase transition", and this multi-authoredbook reviews recent theoretical and experimental studies of this newphenomenon.
The Mixed Phase of Charged AdS Black Holes
Directory of Open Access Journals (Sweden)
Piyabut Burikham
2016-01-01
Full Text Available We study the mixed phase of charged AdS black hole and radiation when the total energy is fixed below the threshold to produce a stable charged black hole branch. The coexistence conditions for the charged AdS black hole and radiation are derived for the generic case when radiation particles carry charge. The phase diagram of the mixed phase is demonstrated for both fixed potential and charge ensemble. In the dual gauge picture, they correspond to the mixed phase of quark-gluon plasma (QGP and hadron gas in the fixed chemical potential and density ensemble, respectively. In the nuclei and heavy-ion collisions at intermediate energies, the mixed phase of exotic QGP and hadron gas could be produced. The mixed phase will condense and evaporate into the hadron gas as the fireball expands.
Emergence and Phase Transitions
Sikkema, Arnold
2006-05-01
Phase transitions are well defined in physics through concepts such as spontaneous symmetry breaking, order parameter, entropy, and critical exponents. But emergence --- also exhibiting whole-part relations (such as top-down influence), unpredictability, and insensitivity to microscopic detail --- is a loosely-defined concept being used in many disciplines, particularly in psychology, biology, philosophy, as well as in physics[1,2]. I will review the concepts of emergence as used in the various fields and consider the extent to which the methods of phase transitions can clarify the usefulness of the concept of emergence both within the discipline of physics and beyond.1. Robert B. Laughlin, A Different Universe: Reinventing Physics from the Bottom Down (New York: Basic Books, 2005). 2. George F.R. Ellis, ``Physics and the Real World'', Physics Today, vol. 58, no. 7 (July 2005) pp. 49-54.
Understanding quantum phase transitions
Carr, Lincoln
2010-01-01
Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth
Phase transitions in geometrothermodynamics
Quevedo, H; Taj, S; Vazquez, A
2010-01-01
Using the formalism of geometrothermodynamics, we investigate the geometric properties of the equilibrium manifold for diverse thermodynamic systems. Starting from Legendre invariant metrics of the phase manifold, we derive thermodynamic metrics for the equilibrium manifold whose curvature becomes singular at those points where phase transitions of first and second order occur. We conclude that the thermodynamic curvature of the equilibrium manifold, as defined in geometrothermodynamics, can be used as a measure of thermodynamic interaction in diverse systems with two and three thermodynamic degrees of freedom.
Fodor, Z
2000-01-01
Recent developments on the four dimensional (4d) lattice studies of the finite temperature electroweak phase transition (EWPT) are summarized. The phase diagram is given in the continuum limit. The finite temperature SU(2)-Higgs phase transition is of first order for Higgs-boson masses m/sub H/<66.5+or-1.4 GeV. Above this endpoint only a rapid cross-over can be seen. The full 4d result agrees completely with that of the dimensional reduction approximation. The Higgs-boson endpoint mass in the standard model (SM) would be 72.1+or-1. 4 GeV. Taking into account the LEP Higgs-boson mass lower bound excludes any EWPT in the SM. A one-loop calculation of the static potential in the SU(2)-Higgs model enables a precise comparison between lattice simulations and perturbative results. The most popular extension of the SM, the minimal supersymmetric SM (MSSM) is also studied on 4d lattices. (17 refs).
A possible evidence of observation of two mixed phases in nuclear collisions
Bugaev, K. A.; Ivanytskyi, A. I.; Sagun, V. V.; Zinovjev, G. M.; Oliinychenko, D. R.; Trubnikov, V. S.; Nikonov, E. G.
2016-11-01
Using an advanced version of the hadron resonance gas model we have found several remarkable irregularities at chemical freeze-out. The most prominent of them are two sets of highly correlated quasi-plateaus in the collision energy dependence of the entropy per baryon, total pion number per baryon, and thermal pion number per baryon which we found at center of mass energies 3.6-4.9 GeV and 7.6-10 GeV. The low energy set of quasi-plateaus was predicted a long time ago. On the basis of the generalized shockadiabat model we demonstrate that the low energy correlated quasi-plateaus give evidence for the anomalous thermodynamic properties of the mixed phase at its boundary to the quark-gluon plasma. The question is whether the high energy correlated quasi-plateaus are also related to some kind of mixed phase. In order to answer this question we employ the results of a systematic meta-analysis of the quality of data description of 10 existing event generators of nucleus-nucleus collisions in the range of center of mass collision energies from 3.1 GeV to 17.3 GeV. These generators are divided into two groups: the first group includes the generators which account for the quark-gluon plasma formation during nuclear collisions, while the second group includes the generators which do not assume the quark-gluon plasma formation in such collisions. Comparing the quality of data description of more than a hundred of different data sets of strange hadrons by these two groups of generators, we find two regions of the equal quality of data description which are located at the center of mass collision energies 4.3-4.9 GeV and 10.-13.5 GeV. These two regions of equal quality of data description we interpret as regions of the hadron-quark-gluon mixed phase formation. Such a conclusion is strongly supported by the irregularities in the collision energy dependence of the experimental ratios of the Lambda hyperon number per proton and positive kaon number per Lambda hyperon. Although at
A possible evidence of observation of two mixed phases in nuclear collisions
Directory of Open Access Journals (Sweden)
Bugaev K.A.
2016-01-01
Full Text Available Using an advanced version of the hadron resonance gas model we have found several remarkable irregularities at chemical freeze-out. The most prominent of them are two sets of highly correlated quasi-plateaus in the collision energy dependence of the entropy per baryon, total pion number per baryon, and thermal pion number per baryon which we found at center of mass energies 3.6-4.9 GeV and 7.6-10 GeV. The low energy set of quasi-plateaus was predicted a long time ago. On the basis of the generalized shockadiabat model we demonstrate that the low energy correlated quasi-plateaus give evidence for the anomalous thermodynamic properties of the mixed phase at its boundary to the quark-gluon plasma. The question is whether the high energy correlated quasi-plateaus are also related to some kind of mixed phase. In order to answer this question we employ the results of a systematic meta-analysis of the quality of data description of 10 existing event generators of nucleus-nucleus collisions in the range of center of mass collision energies from 3.1 GeV to 17.3 GeV. These generators are divided into two groups: the first group includes the generators which account for the quark-gluon plasma formation during nuclear collisions, while the second group includes the generators which do not assume the quark-gluon plasma formation in such collisions. Comparing the quality of data description of more than a hundred of different data sets of strange hadrons by these two groups of generators, we find two regions of the equal quality of data description which are located at the center of mass collision energies 4.3-4.9 GeV and 10.-13.5 GeV. These two regions of equal quality of data description we interpret as regions of the hadron-quark-gluon mixed phase formation. Such a conclusion is strongly supported by the irregularities in the collision energy dependence of the experimental ratios of the Lambda hyperon number per proton and positive kaon number per Lambda
Mixed phases during the phase transitions
Tatsumi, Toshitaka; Maruyama, Toshiki
2011-01-01
Quest for a new form of matter inside compact stars compels us to examine the thermodynamical properties of the phase transitions. We closely consider the first-order phase transitions and the phase equilibrium on the basis of the Gibbs conditions, taking the liquid-gas phase transition in asymmetric nuclear matter as an example. Characteristic features of the mixed phase are figured out by solving the coupled equations for mean-fields and densities of constituent particles self-consistently within the Thomas-Fermi approximation. The mixed phase is inhomogeneous matter composed of two phases in equilibrium; it takes a crystalline structure with a unit of various geometrical shapes, inside of which one phase with a characteristic shape, called "pasta", is embedded in another phase by some volume fraction. This framework enables us to properly take into account the Coulomb interaction and the interface energy, and thereby sometimes we see the mechanical instability of the geometric structures of the mixed phase...
Learning phase transitions by confusion
van Nieuwenburg, Evert P L; Huber, Sebastian D
2016-01-01
Classifying phases of matter is a central problem in physics. For quantum mechanical systems, this task can be daunting owing to the exponentially large Hilbert space. Thanks to the available computing power and access to ever larger data sets, classification problems are now routinely solved using machine learning techniques. Here, we propose to use a neural network based approach to find phase transitions depending on the performance of the neural network after training it with deliberately incorrectly labelled data. We demonstrate the success of this method on the topological phase transition in the Kitaev chain, the thermal phase transition in the classical Ising model, and the many-body-localization transition in a disordered quantum spin chain. Our method does not depend on order parameters, knowledge of the topological content of the phases, or any other specifics of the transition at hand. It therefore paves the way to a generic tool to identify unexplored phase transitions.
Melting Hadrons, Boiling Quarks
Rafelski, Johann
2015-01-01
In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustra...
Phase Transitions of Simple Systems
Berry, Stephen
2008-01-01
This monograph develops a unified microscopic basis for phases and phase changes of bulk matter and small systems in terms of classical physics. The origins of such phase changes are derived from simple but physically relevant models of how transitions between rigid crystalline, glassy and fluid states occur, how phase equilibria arise, and how bulk properties evolve from those of small systems.
Electroweak phase transition in technicolor
Jarvinen, Matti
2010-01-01
Several phenomenologically viable walking technicolor models have been proposed recently. I demonstrate that these models can have first order electroweak phase transitions, which are sufficiently strong for electroweak baryogenesis. Strong dynamics can also lead to several separate transitions at the electroweak scale, with the possibility of a temporary restoration and an extra breaking of the electroweak symmetry. First order phase transitions will produce gravitational waves, which may be detectable at future experiments.
Magnetic resonance of phase transitions
Owens, Frank J; Farach, Horacio A
1979-01-01
Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also
Multiobjective Optimization and Phase Transitions
Seoane, Luís F
2015-01-01
Many complex systems obey to optimality conditions that are usually not simple. Conflicting traits often interact making a Multi Objective Optimization (MOO) approach necessary. Recent MOO research on complex systems report about the Pareto front (optimal designs implementing the best trade-off) in a qualitative manner. Meanwhile, research on traditional Simple Objective Optimization (SOO) often finds phase transitions and critical points. We summarize a robust framework that accounts for phase transitions located through SOO techniques and indicates what MOO features resolutely lead to phase transitions. These appear determined by the shape of the Pareto front, which at the same time is deeply related to the thermodynamic Gibbs surface. Indeed, thermodynamics can be written as an MOO from where its phase transitions can be parsimoniously derived; suggesting that the similarities between transitions in MOO-SOO and Statistical Mechanics go beyond mere coincidence.
Non-equilibrium phase transitions
Henkel, Malte; Lübeck, Sven
2009-01-01
This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.
Comparison of Jet Quenching Formalisms for a Quark-Gluon Plasma "Brick"
Armesto, Nestor; Gale, Charles; Horowitz, William A.; Jacobs, Peter; Jeon, Sangyong; van Leeuwen, Marco; Majumder, Abhijit; Muller, Berndt; Qin, Guang-You; Salgado, Carlos A.; Schenke, Bjorn; Verweij, Marta; Wang, Xin-Nian; Wiedemann, Urs Achim
2012-01-01
We review the currently available formalisms for radiative energy loss of a high-momentum parton in a dense strongly interacting medium. The underlying theoretical framework of the four commonly used formalisms is discussed and the differences and commonalities between the formalisms are highlighted. A quantitative comparison of the single gluon emission spectra as well as the energy loss distributions is given for a model system consisting of a uniform medium with a fixed length of L=2 fm and L=5 fm (the `Brick'). Sizable quantitative differences are found. The largest differences can be attributed to specific approximations that are made in the calculation of the radiation spectrum.
Relativity matters from Einstein's EMC2 to laser particle acceleration and quark-gluon plasma
Rafelski, Johann
2017-01-01
Rafelski presents Special Relativity in a language deemed accessible to students without any topical preparation - avoiding the burden of geometry, tensor calculus, and space-time symmetries – and yet advancing in highly contemporary context all the way to research frontiers. Special Relativity is presented such that nothing remains a paradox or just apparent, but rather is explained. A text of similar character, content, and scope, has not been available before. This book describes Special Relativity when rigid material bodies are introduced describing the reality of body contraction; it shows the relevance of acceleration and the necessary evolution of the theoretical framework when acceleration is critical. This book also presents the evolving views of Einstein about the aether. In addition to a careful and elementary introduction to relativity complete with exercises, worked examples and many discussions, this volume connects to current research topics so that readers can explore Special Relativity fr...
Thermodynamics and equations of state of matter from ideal gas to quark-gluon plasma
Fortov, Vladimir
2016-01-01
The monograph presents a comparative analysis of different thermodynamic models of the equations of state. The basic ideological premises of the theoretical methods and the experiment are considered. The principal attention is on the description of states that are of greatest interest for the physics of high energy concentrations which are either already attained or can be reached in the near future in controlled terrestrial conditions, or are realized in astrophysical objects at different stages of their evolution. Ultra-extreme astrophysical and nuclear-physical applications are also analyzed where the thermodynamics of matter is affected substantially by relativism, high-power gravitational and magnetic fields, thermal radiation, transformation of nuclear particles, nucleon neutronization, and quark deconfinement. The book is intended for a wide range of specialists engaged in the study of the equations of state of matter and high energy density physics, as well as for senior students and postgraduates.
Baryon stopping and quark-gluon plasma production at RHIC and LHC
Energy Technology Data Exchange (ETDEWEB)
Lyakhov, K.
2008-08-15
Strong chromofields developed at early stages of relativistic heavy-ion collisions give rise to the collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of time-dependent chromofield. We have studied sensitivity of the slab trajectories and their final rapidities to the initial strength and decay pattern of the chromofield as well as to the back reaction of produced plasma. This mechanism can naturally explain significant baryon stopping observed at RHIC, an average rapidity loss left angle {delta}y right angle {approx} 2. Using a Bjorken hydrodynamical model with particle producing source we also study the evolution of partonic plasma produced as the result of chromofield decay. Due to the delayed formation and expansion of plasma its maximum energy density is much lower than the initial energy density of the chromofield. It is shown that the net-baryon and produced parton distributions are strongly correlated in the rapidity space. The shape of net-baryon spectra in midrapidity region found in the BRAHMS experiment cannot be reproduced by only one value of chromofield energy density parameter {epsilon}{sub 0}, even if one takes into account novel mechanisms as fluctuations of color charges generated on the slab surface, and weak interaction of baryon-rich matter with produced plasma. The further step to improve our results is to take into account rapidity dependence of saturation momentum as explained in thesis. Different values of parameter {epsilon}{sub 0} has been tried for different variants of chromofield decay to fit BRAHMS data for net-baryon rapidity distribution. In accordance with our analysis, data for fragmentation region correspond to the lower chromofield energy densities than mid-rapidity region. {chi}{sup 2} analysis favors power-law of chromofield decay with corresponding initial chromofield energy density of order {epsilon}{sub f}=30 GeV/fm{sup 3}. (orig.)
Describing the dynamics of the Quark-Gluon Plasma using relativistic viscous hydrodynamics
Yarbrough, Katherine Michelle
Shock diamonds occur in over- or under- expanded supersonic flow. They occur in the unsteady jet of a pulse detonation engine, displaying an array of complex features. Due to the highly transient nature of the flow, it must be captured using high-speed cinematography. A study of image processing of shock reflection in unsteady flow is presented. Using a computer-based environment, a method was developed to process images of shock waves to pinpoint where the shock wave starts. Using mathematical methods, such as Abel transforms, a computer code, written in Matlab, was developed to accurately transform the images to detect density distributions in the form of shock waves. The Mach number and specific heat, pressure, temperature, and density ratios were found using shock polars. Evolution of the flow was examined by transforming images to follow the flow patterns. Seven images were selected and analyzed with the methods developed in this thesis. Then a comparison was done by tracking particles seeded in the flow. The particle tracking revealed velocities which were compared to the Mach numbers found using the shock polars.
Direct Photon Anisotropy and the Time Evolution of the Quark-Gluon Plasma
AUTHOR|(INSPIRE)INSPIRE-00360979
2016-07-22
Historically, the thermal photon inverse slope parameter has been interpreted as the thermalization temperature of the QGP. Observation of the thermal photon spectrum in nucleus-nucleus collisions at the ALICE and PHENIX experiments obtain the inverse slope parameter, but the obtained values are inconsistent with the thermalization temperature predicted by the hydrodynamic model. It has therefore been argued that the inverse slope parameter is not representative of the true QGP thermalization temperature because not all thermal photons are emitted at thermalization. This research will probe this assertion using an investigation of flow and nuclear suppression of thermal photons from ALICE Pb-Pb collisions at '\\sqrt{s_{NN}}=2.76' TeV and comparison to p-p data at '\\sqrt{s_{NN}}=2.76' TeV.
Unified Description of Charmonium Suppression in Quark-Gluon Plasma Medium at RHIC and LHC Energies
Singh, Captain R.; Srivastava, P. K.; Ganesh, S; Mishra, M.
2015-01-01
Recent experimental and theoretical studies suggest that the quarkonia suppression in a thermal QCD medium created at heavy ion collisions is a complex interplay of various physical processes. In this article we put together most of these processes in a unified way to calculate the charmonium survival probability (nuclear modification factor) at energies available at relativistic heavy ion collider (RHIC) and large hadron collider (LHC) experiments. We have included shadowing as the dominant ...
Viewing the Chemical Evolution of the Quark-Gluon Plasma with Charge Balance Functions
Pratt, Scott
2013-01-01
Correlations from charge conservation are affected by when charge/anticharge pairs are created during the course of a relativistic heavy ion collision. For charges created early, balancing charges are typically separated by the order of one unit of spatial rapidity by the end of the collision, whereas those charges produced later in the collision are far more correlated. By analyzing correlations from STAR for different species, I show that one can distinguish the two separate waves of charge creation expected in a high-energy collision, one at early times when the QGP is formed and a second at hadronization. Further, I extract the density of up, down and strange quarks at in the QGP and find agreement at the 20% level with expectations for a chemically thermalized plasma.
Dynamical energy loss as a novel Quark-Gluon Plasma tomographic tool
Djordjevic, Magdalena
2016-12-01
High momentum suppression of light and heavy flavor observables is considered to be an excellent probe of jet-medium interactions in QCD matter created at RHIC and LHC. Utilizing this tool requires accurate suppression predictions for different experiments, probes and experimental conditions, and their unbiased comparison with experimental data. With this goal, we developed the dynamical energy loss formalism towards generating predictions for non-central collisions; the formalism takes into account both radiative and collisional energy loss computed within the same theoretical framework, dynamical (as opposed to static) scattering centers, finite magnetic mass, running coupling and uses no free parameters in comparison with experimental data. Within this formalism, we provided predictions, and a systematic comparison with experimental data, for a diverse set of suppression data: all available light and heavy flavor probes, lower and high momentum ranges, various centrality ranges and various collision energies at RHIC and LHC. We here also provide clear qualitative and quantitative predictions for soon to become available LHC experimental data. Comprehensive agreement between our predictions and experimental results provides a good deal of confidence that our dynamical energy loss formalism can well explain the jet-medium interactions in QGP, which will be further tested by the obtained predictions for the upcoming data. Application of this model, as a novel high-precision tomographic tool of QGP medium, are also discussed.
Hot QCD equation of state and quark-gluon plasma-- finite quark chemical potential
Chandra, Vinod
2008-01-01
We explore the relevance of a hot QCD equation of state of $O[g^6\\ln(1/g)]$, which has been obtained\\cite{avrn} for non-vanishing quark-chemical potentials to heavy ion collisions. Employing a method proposed in a recent paper \\cite{chandra1}, we use the EOS to determine a host of thermodynamic quantities, the energy density, specific heat, entropy dnesity, and the temperature dependence of screening lengths, with the behaviour of QGP at RHIC and LHC in mind. We also investigate the sensitivity of these observables to the quark chemical potential.
What RHIC Experiments and Theory tell us about Properties of Quark-Gluon Plasma ?
Shuryak, E. V.
2004-01-01
This brief review summarizes the main experimental discoveries made at RHIC and then discusses their implications. The robust collective flow phenomena are well described by ideal hydrodynamics, with the Equation of State (EoS) predicted by lattice simulations. However the transport properties turned out to be unexpected, with rescattering cross section one-to-two orders of magnitude larger than expected from perturbative QCD. These and other theoretical developments indicate that Quark-Gluon...
From the QCD vacuum to (strongly coupled) quark-gluon plasma
Shuryak, Edward
2005-04-01
I start with brief discussion of the role of topological objects in the QCD vacuum, reminding why instantons play a special role in chiral symmetry breaking and hadronic physics. Then I move to high temperature T > T c domain, describing briefly some experimental discoveries made at RHIC such as robust collective flow phenomena. They are well described by ideal hydrodynamics, with the Equation of State (EoS) in good agreement with that predicted by lattice simulations. However for hydro to work the transport properties of QGP should be quite remarkable. These and other theoretical developments, especially based on lattice simulations, indicate that matter produced at RHIC is a strongly coupled liquid, sQGP for short. Existence of "new spectroscopy" of states, most of them colored, is expected. We also briefly discuss two other "strongly coupled systems", (i) the strongly coupled supersymmetric theories studied via Maldacena duality; (ii) trapped ultra-cold atoms with very large scattering length.
Short path length pQCD corrections to energy loss in the quark gluon plasma
Kolbe, Isobel
2015-01-01
Recent surprising discoveries of collective behaviour of low-$p_T$ particles in $pA$ collisions at LHC hint at the creation of a hot, fluid-like QGP medium. The seemingly conflicting measurements of non-zero particle correlations and $R_{pA}$ that appears to be consistent with unity demand a more careful analysis of the mechanisms at work in such ostensibly minuscule systems. We study the way in which energy is dissipated in the QGP created in $pA$ collisions by calculating, in pQCD, the short separation distance corrections to the well-known DGLV energy loss formulae that have produced excellent predictions for $AA$ collisions. We find that, shockingly, due to the large formation time (compared to the $1/\\mu$ Debye screening length) assumption that was used in the original DGLV calculation, a highly non-trivial cancellation of correction terms results in a null short path length correction to the DGLV energy loss formula. We investigate the effect of relaxing the large formation time assumption in the final ...
Lower vs. high momentum mass tomography in Quark-Gluon Plasma
Djordjevic, Magdalena; Zivkovic, Lidija
2016-01-01
We here show that at lower energies single particle suppression for different types of probes exhibit a clear mass hierarchy, which is a direct consequence of the differences in the energy loss, rather than the differences in the initial distributions. On the other hand, we predict that the mass hierarchy is not expected at high energies; i.e. the probes of different masses exhibit nearly the same suppression once high momentum measurements are considered. Moreover, we also argue that the same insensitivity on the probe types is valid for jets as well. In particular, the experimental data in the momentum regions where they exist for both types of probes, show similar suppressions of charged hadrons and inclusive jet data. Finally, the available jet data also show (though with large error bars) an overlap between b-jets (heavy) and inclusive jets (light), which we predict will also be exhibited for soon-to-be-measured charm jets. Consequently, our results suggest that single particles in the momentum region be...
Some Applications of Hard Thermal Loop Perturbation Theory in Quark Gluon Plasma
Haque, Najmul
2014-01-01
This thesis is mainly devoted to the study of thermodynamics for quantum Chromodynamics. In this thesis I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to study the thermodynamics of QCD in leading-order, next-to-leading-order and next-to-next-to-leading order at finite temperature and finite chemical potential. I also discuss about various order diagonal and off-diagonale quark number susceptibilities in leading order as well as beyond leading order. For all the observables, I compare our results with available lattice QCD data and we find good agreement. Along-with the computation of thermodynamic quantities of hot and dense matter, I also discuss about low mass dilepton rate from hot and dense medium using both perturbative and non-perturbative models and compare them with those from lattice gauge theory and in-medium hadron gas.
The thermalization of soft modes in non-expanding isotropic quark gluon plasmas
Energy Technology Data Exchange (ETDEWEB)
Blaizot, Jean-Paul, E-mail: jean-paul.blaizot@cea.fr [Institut de Physique Théorique, CNRS/UMR 3681, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Mehtar-Tani, Yacine [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States)
2017-05-15
We discuss the role of elastic and inelastic collisions and their interplay in the thermalization of the quark–gluon plasma. We consider a simplified situation of a static plasma, spatially uniform and isotropic in momentum space. We focus on the small momentum region, which equilibrates first, and on a short time scale. We obtain a simple kinetic equation that allows for an analytic description of the most important regimes. The present analysis suggests that the formation of a Bose condensate, expected when only elastic collisions are present, is strongly hindered by the inelastic, radiative, processes.
Globally Polarized Quark-gluon Plasma in Non-central A+ACollisions
Energy Technology Data Exchange (ETDEWEB)
Liang, Zuo-tang; Wang, Xin-Nian
2004-10-01
Produced partons have large local relative orbital angular momentum along the direction opposite to the reaction plane in the early stage of non-central heavy-ion collisions. Parton scattering is shown to polarize quarks along the same direction due to spin-orbital coupling.Such global quark polarization will lead to many observable consequences,such as left-right asymmetry of hadron spectra, global transverse polarization of thermal photons, dileptons and hadrons. Hadrons from the decay of polarized resonances will have azimuthal asymmetry similar to the elliptic flow. Global hyperon polarization is predicted with indifferent hadronization scenarios and can be easily tested.
The sound generated by a fast parton in the quark-gluon plasma is a crescendo
Neufeld, R. B.; Müller, B.
2009-11-01
The total energy deposited into the medium per unit length by a fast parton traversing a quarkgluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.
The sound generated by a fast parton in the quark-gluon plasma is a crescendo
Energy Technology Data Exchange (ETDEWEB)
Neufeld, R.B.; Mueller, B. [Department of Physics, Duke University, Durham, NC 27708 (United States)
2009-11-01
The total energy deposited into the medium per unit length by a fast parton traversing a quarkgluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.
Towards the quark--gluon plasma Equation of State with dynamical strange and charm quarks
Burger, F; Lombardo, M P; Muller-Preussker, M; Trunin, A
2015-01-01
We present an ongoing project aimed at determining the thermodynamic Equation of State (EoS) of quark--gluon matter from lattice QCD with two generations of dynamical quarks. We employ the Wilson twisted mass implementation for the fermionic fields and the improved Iwasaki gauge action. Relying on $T=0$ data obtained by the ETM Collaboration the strange and charm quark masses are fixed at their physical values, while the pion mass takes four values in the range from 470 MeV down to 210 MeV. The temperature is varied within a fixed--lattice scale approach. The values for the pseudocritical temperature are obtained from various observables. For the EoS we show preliminary results for the pure gluonic contribution obtained at the pion mass value 370 MeV, where we can compare with previously obtained results with $N_f=2$ degenerate light flavours.
Dynamical evolution of the chiral magnetic effect: applications to the quark-gluon plasma
Manuel, Cristina
2015-01-01
We study the dynamical evolution of the so-called chiral magnetic effect in an electromagnetic conductor. To this end, we consider the coupled set of corresponding Maxwell and chiral anomaly equations, and we prove that these can be derived from chiral kinetic theory. After integrating the chiral anomaly equation over space in a closed volume, it leads to a quantum conservation law of the total helicity of the system. A change in the magnetic helicity density comes together with a modification of the chiral fermion density. We study in Fourier space the coupled set of anomalous equations and we obtain the dynamical evolution of the magnetic fields, magnetic helicity density, and chiral fermion imbalance. Depending on the initial conditions we observe how the helicity might be transferred from the fermions to the magnetic fields, or vice versa, and find that the rate of this transfer also depends on the scale of wavelengths of the gauge fields in consideration. We then focus our attention on the quark-gluon pl...
How big are the smallest drops of quark-gluon plasma?
Chesler, Paul M
2016-01-01
Using holographic duality, we present results for both head-on and off-center collisions of Gaussian shock waves in strongly coupled $\\mathcal N = 4$ supersymmetric Yang-Mills theory. The shock waves superficially resemble Lorentz contracted colliding protons. The collisions results in the formation of a plasma whose evolution is well described by viscous hydrodynamics. The size of the produced droplet is $R \\sim 1/T_{\\rm eff}$ where $T_{\\rm eff}$ is the effective temperature, which is the characteristic microscopic scale in strongly coupled plasma. These results demonstrate the applicability of hydrodynamics to microscopically small systems and bolster the notion that hydrodynamics can be applied to heavy-light ion collisions as well as some proton-proton collisions.
Jet-evolution in the quark-gluon plasma from RHIC to the LHC
Energy Technology Data Exchange (ETDEWEB)
Domdey, S. [Institute for Theoretical Physics, University of Heidelberg (Germany); Kopeliovich, B.Z. [Institute for Theoretical Physics, University of Heidelberg (Germany); Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Instituto de Estudios Avanzados en Ciencias e Ingenieria, Centro Cientifico-Tecnologico de Valparaiso, Casilla 110-V, Valparaiso (Chile); Pirner, H.J., E-mail: pir@tphys.uni-heidelberg.d [Institute for Theoretical Physics, University of Heidelberg (Germany)
2011-04-15
The observed suppression of high{sub pperpendicular} hadrons allows different explanations. We discuss two possible scenarios: In scenario 1, parton energy loss from scattering in the hot medium is complemented by final state interactions in the resonance matter. Scenario 2 has an enhanced transport parameter q-hat which is fitted to RHIC data. For LHC, the two scenarios lead to very different predictions for the nuclear modification factor of hadrons. In addition, jet reconstruction allows more specific tests of the mechanisms responsible for jet quenching. We calculate the distribution of partons inside a jet and find different results for the two scenarios.
Initial temperature of the strongly interacting Quark Gluon Plasma created at RHIC
Csanad, Mate
2011-01-01
A 1+3 dimensional solution of relativistic hydrodynamics is analyzed in this paper. Momentum distribution and other observables are calculated from the solution and compared to hadronic measurements from the Relativistic Heavy Ion Collider (RHIC). The solution is compatible with the data, but only the freeze-out point of the evolution is determined. Many equation of states and initial states (initial temperatures) are valid with the same freeze-out distribution, thus the same hadronic observables. The observable that would distinguish between these initial temperatures is momentum distribution of photons, as photons are created throughout the evolution of the fireball created in RHIC collisions. The PHENIX experiment at RHIC measures such data via low invariant mass e+e- pairs. Average temperature from this data is T=221+-23+-18 MeV, while a model calculation with initial temperature 370 MeV agree with the data.
Heavy flavours production in quark-gluon plasma formed in high energy nuclear reactions
Kloskinski, J.
1985-01-01
Results on compression and temperatures of nuclear fireballs and on relative yield of strange and charmed hadrons are given . The results show that temperatures above 300 MeV and large compressions are unlikely achieved in average heavy ion collision. In consequence, thermal production of charm is low. Strange particle production is, however, substantial and indicates clear temperature - threshold behavior.
Learning phase transitions by confusion
van Nieuwenburg, Evert P. L.; Liu, Ye-Hua; Huber, Sebastian D.
2017-02-01
Classifying phases of matter is key to our understanding of many problems in physics. For quantum-mechanical systems in particular, the task can be daunting due to the exponentially large Hilbert space. With modern computing power and access to ever-larger data sets, classification problems are now routinely solved using machine-learning techniques. Here, we propose a neural-network approach to finding phase transitions, based on the performance of a neural network after it is trained with data that are deliberately labelled incorrectly. We demonstrate the success of this method on the topological phase transition in the Kitaev chain, the thermal phase transition in the classical Ising model, and the many-body-localization transition in a disordered quantum spin chain. Our method does not depend on order parameters, knowledge of the topological content of the phases, or any other specifics of the transition at hand. It therefore paves the way to the development of a generic tool for identifying unexplored phase transitions.
Colour-Charged Quark Matter in Astrophysics?
Institute of Scientific and Technical Information of China (English)
QIU Cong-Xin; XU Ren-Xin
2006-01-01
Colour confinement is only a supposition, which has not yet been proven in QCD. Here we propose that macroscopic quark-gluon plasma in astrophysics could hardly maintain colourless because of causality. It is expected that the existence of chromatic strange quark stars as well as chromatic strangelets preserved from the QCD phase transition in the early Universe could be unavoidable if their colourless correspondents do exist.
Hydro+Cascade, Flow, the Equation of State, Predictions and Data
Teaney, D.; LAURET, J.; Shuryak, E. V.
2001-01-01
A Hydro+Cascade model has been used to describe radial and elliptic flow at the SPS and successfully predicted the radial and elliptic flow measured by the both STAR and PHENIX collaborations . Furthermore, a combined description of the radial and elliptic flow for different particle species, restricts the Equation of State(EoS) and points towards an EoS with a phase transition to the Quark Gluon Plasma(QGP) .
Clustering of Color Sources and the Equation of State of the QGP
Srivastava, Brijesh K
2012-01-01
Possible phase transition of strongly interacting matter from hadron to a quark-gluon plasma state have in the past received c onsiderable interest. It has been suggested that this problem might be treated by percolation theory. The clustering of color sources with percolation (CSPM) is used to determine the equation of state (EOS) and the transport coefficient of the Quark-Gl uon Plasma (QGP) produced in central A-A collisions at RHIC and LHC energies.
Hydro+Cascade, Flow, the Equation of State, Predictions and Data
Teaney, D; Shuryak, E V
2002-01-01
A Hydro+Cascade model has been used to describe radial and elliptic flow at the SPS and successfully predicted the radial and elliptic flow measured by the both STAR and PHENIX collaborations . Furthermore, a combined description of the radial and elliptic flow for different particle species, restricts the Equation of State(EoS) and points towards an EoS with a phase transition to the Quark Gluon Plasma(QGP) .
Summary for theory and general session at the RHIC detector workshop
Energy Technology Data Exchange (ETDEWEB)
Kahana, S.
1985-01-01
The topics summarized include: cascade codes treating the components of nuclei as nucleons; a quark gluon cascade code; a treatment of shocks, detonation, and deflagration; putting finite density on the lattice as well as treating the phase transition at a finite critical temperature for vanishing density; theory for dilepton and photon signals and a treatment of the approach to equilibrium; the hydrodynamic evolution of the quark-gluon plasma; and QCD hydrodynamics. 13 refs., 7 figs.
QGP Flow Fluctuations and Characteristics of Higher Moments
Institute of Scientific and Technical Information of China (English)
WANG; Du-juan; L.P.Csernai; D.Strottman; C.Anderlik; CHENG; Yun; ZHOU; Dai-mei; YAN; Yu-liang; CAI; Xu; SA; Ben-hao
2012-01-01
<正>The dynamical development of expanding quark-gluon plasma (QGP) flow is studied in a 3+1D fluid dynamical model with a globally symmetric, initial condition. We minimize fluctuations arising from complex dynamical processes at finite impact parameters and from fluctuating random initial conditions to have a conservative fluid dynamical background estimate for the statistical distributions of the thermo-dynamical parameters. We also avoid a phase transition in the equation of state, and we let the
Strangeness at high temperatures
Schmidt, Christian
2013-01-01
We use up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number fluctuations to extract information on the strange meson and baryon contribution to the low temperature hadron resonance gas, the dissolution of strange hadronic states in the crossover region of the QCD transition and the quasi-particle nature of strange quark contributions to the high temperature quark-gluon plasma phase.
Incommensurate phase transitions
Energy Technology Data Exchange (ETDEWEB)
Currat, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1996-11-01
We review the characteristic aspects of modulated crystals from the point of view of inelastic neutron scattering. We discuss the phenomenological Landau theory of the normal-to-incommensurate displacive instability and its predictions concerning the fluctuation spectrum of the modulated phase. General results on the form of the normal-mode eigenvectors and on the inelastic scattering channels through which they couple to the probe are established using the superspace approach. We illustrate these results on a simple discrete model symmetry and we review available inelastic neutron scattering data on several displacively modulated compounds. (author) 21 figs., 73 refs.
Energy Technology Data Exchange (ETDEWEB)
Scharenberg, R.; Hirsch, A.; Tincknell, M.
1993-09-15
This report discusses the Fermilab experiment E735 which is dedicated to the search for the quark-gluon plasma from proton-antiproton interactions; multifragmentation using the EOS-TPC; STAR R&D; silicon avalanche diodes as direct time-of-flight detectors; and soft photons at the AGS-E855.
PROCEEDINGS OF RIKIN BNL RESEARCH CENTER WORKSHOP - VOLUME 79
Energy Technology Data Exchange (ETDEWEB)
SAMIOS,N.
2006-02-16
Since the earliest days of ultra-relativistic heavy ion physics, there has been interest in strange particle production. Originally, an anomalously large strangeness production was believed to be a signature of the Quark Gluon Plasma. Now the flavor composition of the plasma as reflected in the ratios of abundances of strange and non-strange particles is believed by advocates to tell us the temperature and baryon number density of the Quark Gluon Plasma at decoupling. In addition, there are arguments that suggest that the abundances of strange particles might at intermediate energy or at non-central rapidity, signal the existence of a critical end point of phase transitions in the baryon number chemical potential temperature plane. The purpose of this workshop is to assess the current theoretical and experimental understanding of strangeness production for ultra-relativistic heavy ion collisions.
Matter in extremis: Ultrarelativistic nuclear collisions at RHIC
Energy Technology Data Exchange (ETDEWEB)
Jacobs, Peter; Wang, Xin-Nian
2004-08-20
We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at {radical}s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state.
Phase transitions in operational risk.
Anand, Kartik; Kühn, Reimer
2007-01-01
In this paper we explore the functional correlation approach to operational risk. We consider networks with heterogeneous a priori conditional and unconditional failure probability. In the limit of sparse connectivity, self-consistent expressions for the dynamical evolution of order parameters are obtained. Under equilibrium conditions, expressions for the stationary states are also obtained. Consequences of the analytical theory developed are analyzed using phase diagrams. We find coexistence of operational and nonoperational phases, much as in liquid-gas systems. Such systems are susceptible to discontinuous phase transitions from the operational to nonoperational phase via catastrophic breakdown. We find this feature to be robust against variation of the microscopic modeling assumptions.
Symmetry structure and phase transitions
Indian Academy of Sciences (India)
Ashok Goyal; Meenu Dahiya; Deepak Chandra
2003-05-01
We study chiral symmetry structure at ﬁnite density and temperature in the presence of external magnetic ﬁeld and gravity, a situation relevant in the early Universe and in the core of compact stars. We then investigate the dynamical evolution of phase transition in the expanding early Universe and possible formation of quark nuggets and their survival.
Phase transitions in finite systems
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire
2002-07-01
In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)
Phase transitions and critical phenomena
Domb, Cyril
2001-01-01
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. It has moved into a central place in condensed matter studies.Statistical physics, and more specifically, the theory of transitions between states of matter, more or less defines what we know about 'everyday' matter and its transformations.The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable in
Sliding Over a Phase Transition
Tosatti, Erio; Benassi, Andrea; Vanossi, Andrea; Santoro, Giuseppe E.
2011-03-01
The frictional response experienced by a stick-slip slider when a phase transition occurs in the underlying solid substrate is a potentially exciting, poorly explored problem. We show, based on 2-dimensional simulations modeling the sliding of a nanotip, that indeed friction may be heavily affected by a continuous structural transition. First, friction turns nonmonotonic as temperature crosses the transition, peaking at the critical temperature Tc where fluctuations are strongest. Second, below Tc friction depends upon order parameter directions, and is much larger for those where the frictional slip can cause a local flip. This may open a route towards control of atomic scale friction by switching the order parameter direction by an external field or strain, with possible application to e.g., displacive ferroelectrics such as BaTi O3 , as well as ferro- and antiferro-distortive materials. Supported by project ESF FANAS/AFRI sponsored by the Italian Research Council (CNR).
Electroweak phase transition recent results
Csikor, Ferenc
2000-01-01
Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.
Phase transitions at finite density
Friman, Bengt
2012-01-01
I discuss the analytic structure of thermodynamic quantities for complex values of thermodynamic variables within Landau theory. In particular, the singularities connected with phase transitions of second order, first order and cross over types are examined. A conformal mapping is introduced, which may be used to explore the thermodynamics of strongly interacting matter at finite values of the baryon chemical potential $\\mu$ starting from lattice QCD results at $\\mu^{2}\\leq 0$. This method allows us to improve the convergence of a Taylor expansion about $\\mu=0$ and to enhance the sensitivity to physical singularities in the complex $\\mu$ plane. The technique is illustrated by an application to a second-order transition in a chiral effective model.
Interacting Weyl fermions: Phases, phase transitions, and global phase diagram
Roy, Bitan; Goswami, Pallab; Juričić, Vladimir
2017-05-01
We study the effects of short-range interactions on a generalized three-dimensional Weyl semimetal, where the band touching points act as the (anti)monopoles of Abelian Berry curvature of strength n . We show that any local interaction has a negative scaling dimension -2 /n . Consequently, all Weyl semimetals are stable against weak short-range interactions. For sufficiently strong interactions, we demonstrate that the Weyl semimetal either undergoes a first-order transition into a band insulator or a continuous transition into a symmetry breaking phase. A translational symmetry breaking axion insulator and a rotational symmetry breaking semimetal are two prominent candidates for the broken symmetry phase. At the one-loop order, the correlation length exponent for continuous transitions is ν =n /2 , indicating their non-Gaussian nature for any n >1 . We also discuss the scaling of the thermodynamic and transport quantities in general Weyl semimetals as well as inside broken symmetry phases.
Phase Transition in Tensor Models
Delepouve, Thibault
2015-01-01
Generalizing matrix models, tensor models generate dynamical triangulations in any dimension and support a $1/N$ expansion. Using the intermediate field representation we explicitly rewrite a quartic tensor model as a field theory for a fluctuation field around a vacuum state corresponding to the resummation of the entire leading order in $1/N$ (a resummation of the melonic family). We then prove that the critical regime in which the continuum limit in the sense of dynamical triangulations is reached is precisely a phase transition in the field theory sense for the fluctuation field.
Gibbs measures and phase transitions
Georgii, Hans-Otto
2011-01-01
From a review of the first edition: ""This book […] covers in depth a broad range of topics in the mathematical theory of phase transition in statistical mechanics. […] It is in fact one of the author's stated aims that this comprehensive monograph should serve both as an introductory text and as a reference for the expert."" (F. Papangelou, Zentralblatt MATH) The second edition has been extended by a new section on large deviations and some comments on the more recent developments in the area.
Light scattering near phase transitions
Cummins, HZ
1983-01-01
Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals.A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.
Phase transitions and critical phenomena
Domb, Cyril
2000-01-01
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. No longer an area of specialist interest, it has acquired a central focus in condensed matter studies. The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable information on important recent developments.The two review articles in this volume complement each other in a remarkable way. Both deal with what m
Quark Deconfinement Phase Transition in Neutron Stars
Alaverdyan, G B
2009-01-01
The hadron-quark phase transition in the interior of compact stars is investigated, when the transition proceeds through a mixed phase. The hadronic phase is described in the framework of relativistic mean-field theory, when also the scalar-isovector delta-meson mean-field is taken into account. The changes of the parameters of phase transition caused by the presence of delta-meson field are explored. The results of calculation of structure of the mixed phase (Glendenning construction) are compared with the results of usual first-order phase transition (Maxwell construction).
Interacting Weyl fermions: Phases, phase transitions and global phase diagram
Roy, Bitan; Juricic, Vladimir
2016-01-01
We study the effects of short-range interactions on a generalized three-dimensional Weyl semimetal, where the band touching points act as the (anti)monopoles of Abelian Berry curvature of strength $n$. We show that any local interaction has a \\emph{negative} scaling dimension $-2/n$. Consequently all Weyl semimetals are stable against weak short-range interactions. For sufficiently strong interactions, we demonstrate that the Weyl semimetal either undergoes a first order transition into a band insulator or a continuous transition into a symmetry breaking phase. A translational symmetry breaking axion insulator and a rotational symmetry breaking semimetal are two prominent candidates for the broken symmetry phase. At one loop level, the correlation length exponent for continuous transitions is $\
QCD Phase Transitions, Volume 15
Energy Technology Data Exchange (ETDEWEB)
Schaefer, T.; Shuryak, E.
1999-03-20
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.
The Structural Phase Transition in Solid DCN
DEFF Research Database (Denmark)
Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.
1976-01-01
Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low energ...... energies and showed “softening” as the transition was approached from above.......Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low...
QGP phase transition and multiplicity fluctuations
Institute of Scientific and Technical Information of China (English)
杨纯斌; 王晓荣; 蔡勖
1997-01-01
The scaled factorial moments in QGP phase transitions are studied analytically by the extended Ginzburg-Landau model.The dependence of InFq on phase space interval is different for the first- and second-order QGP phase transitions.When lnFq are fitted to polynomials of X=δ1/3,the relative sign between the fitted coefficients of X and bq,l calculated theoretically can be used to judge the order of phase transitions.Two sets of experimental data are reanalysed and the phase transitions are the first order for one set of data but the second order for another.
Current fluctuations at a phase transition
Gerschenfeld, A.; Derrida, B.
2011-10-01
The ABC model is a simple diffusive one-dimensional non-equilibrium system which exhibits a phase transition. Here we show that the cumulants of the currents of particles through the system become singular near the phase transition. At the transition, they exhibit an anomalous dependence on the system size (an anomalous Fourier's law). An effective theory for the dynamics of the single mode which becomes unstable at the transition allows one to predict this anomalous scaling.
Cosmological phase transitions from lattice field theory
Energy Technology Data Exchange (ETDEWEB)
Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2011-11-22
In this proceedings contribution we discuss the fate of the electroweak and the quantum chromodynamics phase transitions relevant for the early stage of the universe at non-zero temperature. These phase transitions are related to the Higgs mechanism and the breaking of chiral symmetry, respectively. We will review that non-perturbative lattice field theory simulations show that these phase transitions actually do not occur in nature and that physical observables show a completely smooth behaviour as a function of the temperature.
Holographic Phase Transition Probed by Nonlocal Observables
Directory of Open Access Journals (Sweden)
Xiao-Xiong Zeng
2016-01-01
Full Text Available From the viewpoint of holography, the phase structure of a 5-dimensional Reissner-Nordström-AdS black hole is probed by the two-point correlation function, Wilson loop, and entanglement entropy. As the case of thermal entropy, we find for all the probes that the black hole undergoes a Hawking-Page phase transition, a first-order phase transition, and a second-order phase transition successively before it reaches a stable phase. In addition, for these probes, we find that the equal area law for the first-order phase transition is valid always and the critical exponent of the heat capacity for the second-order phase transition coincides with that of the mean field theory regardless of the size of the boundary region.
When is the deconfinement phase transition universal?
Holland, K; Wiese, U J
2003-01-01
Pure Yang-Mills theory has a finite-temperature phase transition, separating the confined and deconfined bulk phases. Svetitsky and Yaffe conjectured that if this phase transition is of second order, it belongs to the universality class of transitions for particular scalar field theories in one lower dimension. We examine Yang-Mills theory with the symplectic gauge groups Sp(N). We find new evidence supporting the Svetitsky-Yaffe conjecture and make our own conjecture as to which gauge theories have a universal second order deconfinement phase transition.
Phase transitions of quadrupolar fluids
O'Shea, Seamus F.; Dubey, Girija S.; Rasaiah, Jayendran C.
1997-07-01
Gibbs ensemble simulations are reported for Lennard-Jones particles with embedded quadrupoles of strength Q*=Q/(ɛσ5)1/2=2.0 where ɛ and σ are the Lennard-Jones parameters. Calculations revealing the effect of the dispersive forces on the liquid-vapor coexistence were carried out by scaling the attractive r-6 term in the Lennard-Jones pair potential by a factor λ ranging from 0 to 1. Liquid-vapor coexistence is observed for all values of λ including λ=0 for Q*=2.0, unlike the corresponding dipolar fluid studied by van Leeuwen and Smit et al. [Phys. Rev. Lett. 71, 3991 (1993)] which showed no phase transition below λ=0.35 when the reduced dipole moment μ*=2.0. The simulation data are analyzed to estimate the critical properties of the quadrupolar fluid and their dependence on the strength λ of the dispersive force. The critical temperature and pressure show a clear quadratic dependence on λ, while the density is less confidently identified as being linear in λ. The compressibility is roughly linear in λ.
Phase transitions in the web of science
Phillips, J. C.
2015-06-01
The Internet age is changing the structure of science, and affecting interdisciplinary interactions. Publication profiles connecting mathematics with molecular biology and condensed matter physics over the last 40 years exhibit common phase transitions indicative of the critical role played by specific interdisciplinary interactions. The strengths of the phase transitions quantify the importance of interdisciplinary interactions.
Quantum Phase Transitions in a Finite System
Leviatan, A
2006-01-01
A general procedure for studying finite-N effects in quantum phase transitions of finite systems is presented and applied to the critical-point dynamics of nuclei undergoing a shape-phase transition of second-order (continuous), and of first-order with an arbitrary barrier.
The Structural Phase Transition in Solid DCN
DEFF Research Database (Denmark)
Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.
1975-01-01
Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase change from a tetragonal to an orthorhombic form at 160K is a first-order transition. A transverse acoustic phonon mode, which has the symmetry of the phase change, was observed at very low energies...... and showed 'softening' as the transition temperature was approached from above....
SUSY and the Electroweak Phase Transition
Farrar, Glennys R S; Farrar, Glennys R.; Losada, Marta
1996-01-01
We analyze the effective 3 dimensional theory previously constructed for the MSSM and multi-Higgs models to determine the regions of parameter space in which the electroweak phase transition is sufficiently strong for a $B+L$ asymmetry to survive in the low temperature phase. We find that the inclusion of all supersymmetric scalars and all 1-loop corrections has the effect of enhancing the strength of the phase transition. Without a light stop or extension of the MSSM the phase transition is sufficiently first order only if the lightest Higgs mass $M_{h}\\lsi 70$ GeV and $tan\\beta\\lsi 1.75$.
A Hybrid Model for QCD Deconfining Phase Boundary
Srivastava, P K
2012-01-01
Intensive search for a proper and realistic equations of state (EOS) is still continued for studying the phase diagram existing between quark gluon plasma (QGP) and hadron gas (HG) phases. Lattice calculations provide such EOS for the strongly interacting matter at finite temperature ($T$) and vanishing baryon chemical potential ($\\mu_{B}$). These calculations are of limited use at finite $\\mu_{B}$ due to the appearance of notorious sign problem. In the recent past, we had constructed a hybrid model description for the QGP as well as HG phases where we make use of a new excluded-volume model for HG and a thermodynamically-consistent quasiparticle model for the QGP phase and used them further to get QCD phase boundary and a critical point. Since then many lattice calculations have appeared showing various thermal and transport properties of QCD matter at finite $T$ and $\\mu_{B}=0$. We test our hybrid model by reproducing the entire data for strongly interacting matter and predict our results at finite $\\mu_{B}...
Chirality effects on 2D phase transitions
DEFF Research Database (Denmark)
Scalas, E.; Brezesinski, G.; Möhwald, H.
1996-01-01
-nearest neighbours (NNN) and an NNN-distorted lattice is observed. At 5 degrees C, the transition pressure is 15 mN m(-1), whereas at 20 degrees C it is 18 mN m(-1). Chirality destroys this transition: the pure enantiomer always exhibits an oblique lattice with tilted molecules, and the azimuths of tilt...... and distortion continuously vary from a direction close to NN to a direction close to NNN. The nature of the phase transition and the influence of chirality on it are discussed within the framework of Landau's theory of phase transitions....
Cosmological perturbations from an inhomogeneous phase transition
Energy Technology Data Exchange (ETDEWEB)
Matsuda, Tomohiro, E-mail: matsuda@sit.ac.j [Laboratory of Physics, Saitama Institute of Technology, Fusaiji, Okabe-machi, Saitama 369-0293 (Japan)
2009-07-21
A mechanism for generating metric perturbations in inflationary models is considered. Long-wavelength inhomogeneities of light scalar fields in a decoupled sector may give rise to superhorizon fluctuations of couplings and masses in the low-energy effective action. Cosmological phase transitions may then occur that are not simultaneous in space, but occur with time lags in different Hubble patches that arise from the long-wavelength inhomogeneities. Here an interesting model in which cosmological perturbations may be created at the electroweak phase transition is considered. The results show that phase transitions may be a generic source of non-Gaussianity.
Phase transitions in dissipative Josephson chains
Energy Technology Data Exchange (ETDEWEB)
Bobbert, P.A.; Fazio, R.; Schoen, G. (Department of Applied Physics, Delft University of Technology, 2628 CJ Delft, The Netherlands (NL)); Zimanyi, G.T. (Department of Physics, University of California, Davis, Davis, California 95616 (USA))
1990-03-01
We study the zero-temperature phase transitions of a chain of Josephson junctions, taking into account the quantum fluctuations due to the charging energy and the effects of an Ohmic dissipation. We map the problem onto a generalized Coulomb gas model, which then is transformed into a sine-Gordon field theory. Apart from the expected dipole unbinding transition, which describes a transition between globally superconducting and resistive behavior, we find a quadrupole unbinding transition at a critical strength of the dissipation. This transition separates two superconducting states characterized by different local properties.
From hadron gas to quark matter, 1
Hagedorn, Rolf
1981-01-01
An analytical, non-perturbative description of a strongly interacting hadron gas is presented. Its main features are: the formulation is relativistically covariant, hadrons have finite extensions which are treated a la Van der Waals and their strong interactions are simulated by a hadronic mass spectrum generated by a bootstrap equation under the constraints of baryon number conservation. The system exhibits a singularity, which has the typical features of a phase transition gas to liquid, but which the authors interpret here as the transition into a quark-gluon plasma phase, which, however, cannot be described by this model. (16 refs).
Conductor-insulator quantum phase transitions
Trivedi, Nandini; Valles, James M
2012-01-01
When many particles come together how do they organise themselves? And what destroys this organisation? Combining experiments and theory, this book describes intriguing quantum phases - metals, superconductors and insulators - and transitions between them.
Magnetic Fields from the Electroweak Phase Transition
Törnkvist, O
1998-01-01
I review some of the mechanisms through which primordial magnetic fields may be created in the electroweak phase transition. I show that no magnetic fields are produced initially from two-bubble collisions in a first-order transition. The initial field produced in a three-bubble collision is computed. The evolution of fields at later times is discussed.
The transition to chaotic phase synchronization
DEFF Research Database (Denmark)
Mosekilde, E.; Laugesen, J. L.; Zhusubaliyev, Zh. T.
2012-01-01
The transition to chaotic phase synchronization for a periodically driven spiral-type chaotic oscillator is known to involve a dense set of saddle-node bifurcations. By following the synchronization transition through the cascade of period-doubling bifurcations in a forced Ro¨ssler system, this p...
Song, Jun; Liang, Zuo-tang
2014-01-01
We propose a new kind of two-particle correlation of identified hadrons in longitudinal rapidity space, called $G_{\\alpha\\beta}(y_{\\alpha},y_{\\beta})$, which can reflect clearly the charge correlations of hot quark system produced in AA collisions at LHC energies. It is derived from the basic scenario of quark combination mechanism of hadron production. Like the elliptic flow of identified hadrons at intermediate transverse momentum, this correlation is independent of the absolute hadronic yields but dependent only on the flavor compositions of hadrons, and thus exhibits interesting properties for different kinds of hadron species. We suggest the measurement of this observable in AA collisions at LHC to gain more insights into the charge correlation properties of produced hot quark matter.
Singh, R., Captain; Srivastava, P. K.; Ganesh, S.; Mishra, M.
2015-09-01
Recent experimental and theoretical studies suggest that the quarkonium suppression in a thermal QCD medium created in heavy ion collisions is a complex interplay of various physical processes. In this article we put together most of these processes in a unified way to calculate the charmonium survival probability (nuclear modification factor) at energies available at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) experiments. We include shadowing as the dominant cold-nuclear-matter effect. Further, gluonic dissociation and collision damping are included, which provide width to the spectral function of charmonia in a thermal medium and cause the dissociation of charmonium along with the usual color screening. We include color screening by using our recently proposed modified Chu-Matsui model. Furthermore, we incorporate the recombination of uncorrelated charm and anticharm quarks for the regeneration of charmonium over the entire temporal evolution of the QGP medium. Finally, we do a feed-down correction from the excited states to calculate the survival probability of charmonium. We find that our unified model suitably and simultaneously describes the experimental nuclear modification data of J /ψ at RHIC and LHC.
Li, Shiyong; Yee, Ho-Ung
2016-01-01
We compute the jet quenching parameter $\\hat q$ of QCD plasma in the presence of strong magnetic field in both weakly and strongly coupled regimes. In weakly coupled regime, we compute $\\hat q$ in perturbative QCD at complete leading order (that is, leading log as well as the constant under the log) in QCD coupling constant $\\alpha_s$, assuming the hierarchy of scales $\\alpha_s eB\\ll T^2\\ll eB$. We consider two cases of jet orientations with respect to the magnetic field: 1) the case of jet moving parallel to the magnetic field, 2) the case jet moving perpendicular to the magnetic field. In the former case, we find $\\hat q\\sim \\alpha_s^2 (eB)T\\log(1/\\alpha_s)$, while in the latter we have $\\hat q\\sim \\alpha_s^2 (eB)T\\log(T^2/\\alpha_seB)$. In both cases, this leading order result arises from the scatterings with thermally populated lowest Landau level quarks. In strongly coupled regime described by AdS/CFT correspondence, we find $\\hat q\\sim \\sqrt{\\lambda}(eB)T$ or $\\hat q\\sim\\sqrt{\\lambda}\\sqrt{eB}T^2$ in the...
Quasi-Particle Degrees of Freedom versus the Perfect Fluid as Descriptors of the Quark-Gluon Plasma
Levy, L A Linden; Rosen, C; Steinberg, P
2007-01-01
Approaches for understanding the hydrodynamic flow of the hot and dense medium created in the collisions of relativistic heavy ions are discussed, focusing on their implications for scenarios where quasi-particles are assumed to carry the thermodynamic degrees of freedom. Well-defined quasi-particle degrees of freedom are in principle inconsistent with inviscid hydrodynamics, which implies a vanishing mean free path. However, quasi-particles may play a role as the density of the medium decreases. It is thus an open question whether the freeze-out of the fluid stage proceeds directly into hadrons, or via a fleeting intermediate state with effectively-free constituent quarks, which may well be identified with QCD quasi-particle degrees of freedom. The empirical observation of the ``$n_q$'' scaling of elliptic flow \\cite{Adare:2006ti} (the universality of $v_2/n_q$ as a function of $(m_{T}-m)/n_q$, where $n_q$ is the number of constituent quarks in the hadron) is scrutinized in detail. It is found that, at all t...
Transit time MESFET phase shifter
Walters, Peter C.; Roger D. Pollard; Richardson, John R.
1992-01-01
The phase shift of a signal through a common-source MESFET can be changed with little effect on the amplitude by altering the gate-drain spacing. The feasibility of employing this principle to realize a highly compact, monolithic phase shifter has been investigated. The behaviour of the devices with differing gate-drain spacing has been measured and modelled and a design for a monolithic implementation is presented.
Molecular markers of phase transition in locusts
Institute of Scientific and Technical Information of China (English)
ARNOLD DE LOOF; ILSE CLAEYS; GERT SIMONET; PETER VERLEYEN; TIM VANDERSMISSEN; FILIP SAS; JURGEN HUYBRECHTS
2006-01-01
The changes accompanying the transition from the gregarious to the solitary phase state in locusts are so drastic that for a long time these phases were considered as distinct species. It was Boris Uvarov who introduced the concept of polyphenism. Decades of research revealed that phase transition implies changes in morphometry, the color of the cuticle, behavior and several aspects of physiology. In particular, in the recent decade, quite a number of molecular studies have been undertaken to uncover phase-related differences.They resulted in novel insights into the role of corazonin, neuroparsins, some protease inhibitors, phenylacetonitrile and so on. The advent of EST-databases of locusts (e.g. Kang et al., 2004) is a most encouraging novel development in physiological and behavioral locust research. Yet, the answer to the most intriguing question, namely whether or not there is a primordial molecular inducer of phase transition, is probably not within reach in the very near future.
Polymorphic phase transition in Superhydrous Phase B
Koch-Müller, M.; Dera, P.; Fei, Y.; Hellwig, H.; Liu, Z.; Orman, J. Van; Wirth, R.
2005-09-01
We synthesized superhydrous phase B (shy-B) at 22 GPa and two different temperatures: 1200°C (LT) and 1400°C (HT) using a multi-anvil apparatus. The samples were investigated by transmission electron microscopy (TEM), single crystal X-ray diffraction, Raman and IR spectroscopy. The IR spectra were collected on polycrystalline thin-films and single crystals using synchrotron radiation, as well as a conventional IR source at ambient conditions and in situ at various pressures (up to 15 GPa) and temperatures (down to -180°C). Our studies show that shy-B exists in two polymorphic forms. As expected from crystal chemistry, the LT polymorph crystallizes in a lower symmetry space group ( Pnn2), whereas the HT polymorph assumes a higher symmetry space group ( Pnnm). TEM shows that both modifications consist of nearly perfect crystals with almost no lattice defects or inclusions of additional phases. IR spectra taken on polycrystalline thin films exhibit just one symmetric OH band and 29 lattice modes for the HT polymorph in contrast to two intense but asymmetric OH stretching bands and at least 48 lattice modes for the LT sample. The IR spectra differ not only in the number of bands, but also in the response of the bands to changes in pressure. The pressure derivatives for the IR bands are higher for the HT polymorph indicating that the high symmetry form is more compressible than the low symmetry form. Polarized, low-temperature single-crystal IR spectra indicate that in the LT-polymorph extensive ordering occurs not only at the Mg sites but also at the hydrogen sites.
Polymorphic Phase Transition in Superhydrous Phase B
Energy Technology Data Exchange (ETDEWEB)
Koch-Muller,M.; Dera, P.; Fei, Y.; Hellwig, H.; Liu, Z.; Van Orman, J.; Wirth, R.
2005-01-01
We synthesized superhydrous phase B (shy-B) at 22 GPa and two different temperatures: 1200 C (LT) and 1400 C (HT) using a multi-anvil apparatus. The samples were investigated by transmission electron microscopy (TEM), single crystal X-ray diffraction, Raman and IR spectroscopy. The IR spectra were collected on polycrystalline thin-films and single crystals using synchrotron radiation, as well as a conventional IR source at ambient conditions and in situ at various pressures (up to 15 GPa) and temperatures (down to -180 C). Our studies show that shy-B exists in two polymorphic forms. As expected from crystal chemistry, the LT polymorph crystallizes in a lower symmetry space group (Pnn2), whereas the HT polymorph assumes a higher symmetry space group (Pnnm). TEM shows that both modifications consist of nearly perfect crystals with almost no lattice defects or inclusions of additional phases. IR spectra taken on polycrystalline thin films exhibit just one symmetric OH band and 29 lattice modes for the HT polymorph in contrast to two intense but asymmetric OH stretching bands and at least 48 lattice modes for the LT sample. The IR spectra differ not only in the number of bands, but also in the response of the bands to changes in pressure. The pressure derivatives for the IR bands are higher for the HT polymorph indicating that the high symmetry form is more compressible than the low symmetry form. Polarized, low-temperature single-crystal IR spectra indicate that in the LT-polymorph extensive ordering occurs not only at the Mg sites but also at the hydrogen sites.
Contemporary research of dynamically induced phase transitions
Hull, L. M.
2017-01-01
Dynamically induced phase transitions in metals, within the present discussion, are those that take place within a time scale characteristic of the shock waves and any reflections or rarefactions involved in the loading structure along with associated plastic flow. Contemporary topics of interest include the influence of loading wave shape, the effect of shear produced by directionality of the loading relative to the sample dimensions and initial velocity field, and the loading duration (kinetic effects, hysteresis) on the appearance and longevity of a transformed phase. These topics often arise while considering the loading of parts of various shapes with high explosives, are typically two or three-dimensional, and are often selected because of the potential of the transformed phase to significantly modify the motion. In this paper, we look at current work on phase transitions in metals influenced by shear reported in the literature, and relate recent work conducted at Los Alamos on iron's epsilon phase transition that indicates a significant response to shear produced by reflected elastic waves. A brief discussion of criteria for the occurrence of stress induced phase transitions is provided. Closing remarks regard certain physical processes, such as fragmentation and jet formation, which may be strongly influenced by phase transitions.
Deconfinement in the presence of a strong magnetic background: an exercise within the MIT bag model
Fraga, Eduardo S
2012-01-01
We study the effect of a very strong homogeneous magnetic field B on the thermal deconfinement transition within the simplest phenomenological approach: the MIT bag pressure for the quark-gluon plasma and a gas of pions for the hadronic sector. Even though the model is known to be crude in numerical precision and misses the correct nature of the (crossover) transition, it provides a simple setup for the discussion of some subtleties of vacuum and thermal contributions in each phase, and should provide a reasonable qualitative description of the critical temperature in the presence of B. We find that the critical temperature decreases.
Deconfinement in the presence of a strong magnetic background: An exercise within the MIT bag model
Fraga, Eduardo S.; Palhares, Letícia F.
2012-07-01
We study the effect of a very strong homogeneous magnetic field B on the thermal deconfinement transition within the simplest phenomenological approach: the MIT bag pressure for the quark-gluon plasma and a gas of pions for the hadronic sector. Even though the model is known to be crude in numerical precision and misses the correct nature of the (crossover) transition, it provides a simple setup for the discussion of some subtleties of vacuum and thermal contributions in each phase, and should provide a reasonable qualitative description of the critical temperature in the presence of B. We find that the critical temperature decreases, saturating for very large fields.
An absorbing phase transition from a structured active particle phase
Energy Technology Data Exchange (ETDEWEB)
Lopez, Cristobal [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain); Ramos, Francisco [Departamento de Electromagnetismo y Fisica de la Materia and Instituto de Fisica Teorica y Computacional Carlos I, Facultad de Ciencias, Universidad de Granada, 18071 Granada (Spain); Hernandez-GarcIa, Emilio [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain)
2007-02-14
In this work we study the absorbing state phase transition of a recently introduced model for interacting particles with neighbourhood-dependent reproduction rates. The novelty of the transition is that as soon as the active phase is reached by increasing a control parameter a periodically arranged structure of particle clusters appears. A numerical study in one and two dimensions shows that the system falls into the directed percolation universality class.
Magnetic phase transitions in layered intermetallic compounds
Mushnikov, N. V.; Gerasimov, E. G.; Rosenfeld, E. V.; Terent'ev, P. B.; Gaviko, V. S.
2012-10-01
Magnetic, magnetoelastic, and magnetotransport properties have been studied for the RMn2Si2 and RMn6Sn6 (R is a rare earth metal) intermetallic compounds with natural layered structure. The compounds exhibit wide variety of magnetic structures and magnetic phase transitions. Substitution of different R atoms allows us to modify the interatomic distances and interlayer exchange interactions thus providing the transition from antiferromagnetic to ferromagnetic state. Near the boundary of this transition the magnetic structures are very sensitive to the external field, temperature and pressure. The field-induced transitions are accompanied by considerable change in the sample size and resistivity. It has been shown that various magnetic structures and magnetic phase transitions observed in the layered compounds arise as a result of competition of the Mn-Mn and Mn-R exchange interactions.
Numerical Study of Phase Transition in Thermoviscoelasticity
Institute of Scientific and Technical Information of China (English)
ShaoqingTANG
1997-01-01
We study the spatially periodic problem of thermoviscoelasticity with nonmonotone structure relations.By pseudo-spectral method.we demosnstrate numerically phase transitions for certain symmetric initial data.Without symmetry,the simulations show that a translation occurs for the phase boundary.
Phase Transition in the Simplest Plasma Model
Iosilevskiy, Igor
2009-01-01
We have investigated the phase transition of the gas-liquid type, with an upper critical point, in a variant of the One Component Plasma model (OCP) that has a uniform but compressible compensating background. We have calculated the parameters of the critical and triple points, spinodals, and two-phase coexistence curves (binodals). We have analyzed the connection of this simplest plasma phase transition with anomalies in the spatial charge profiles of equilibrium non-uniform plasma in the local-density approximations of Thomas-Fermi or Poisson-Boltzmann-type.
Theory of phase transitions rigorous results
Sinai, Ya G
1982-01-01
Theory of Phase Transitions: Rigorous Results is inspired by lectures on mathematical problems of statistical physics presented in the Mathematical Institute of the Hungarian Academy of Sciences, Budapest. The aim of the book is to expound a series of rigorous results about the theory of phase transitions. The book consists of four chapters, wherein the first chapter discusses the Hamiltonian, its symmetry group, and the limit Gibbs distributions corresponding to a given Hamiltonian. The second chapter studies the phase diagrams of lattice models that are considered at low temperatures. The no
End point of the electroweak phase transition
Csikor, Ferenc; Heitger, J; Aoki, Y; Ukawa, A
1999-01-01
We study the hot electroweak phase transition (EWPT) by 4-dimensional lattice simulations on lattices with symmetric and asymmetric lattice spacings and give the phase diagram. A continuum extrapolation is done. We find first order phase transition for Higgs-boson masses $m_H<66.5 \\pm 1.4$ GeV. Above this end point a rapid cross-over occurs. Our result agrees with that of the dimensional reduction approach. It also indicates that the fermionic sector of the Standard Model (SM) may be included perturbatively. We get for the SM end point $72.4 the SM.
Phase Transition Induced Fission in Lipid Vesicles
Leirer, C; Myles, V M; Schneider, M F
2010-01-01
In this work we demonstrate how the first order phase transition in giant unilamellar vesicles (GUVs) can function as a trigger for membrane fission. When driven through their gel-fluid phase transition GUVs exhibit budding or pearl formation. These buds remain connected to the mother vesicle presumably by a small neck. Cooling these vesicles from the fluid phase (T>Tm) through the phase transition into the gel state (T
Centrality dependence of K+ produced in Pb+Pb collisions at 158 GeV per nucleon
Arsenescu, R; Baglin, C; Beck, H P; Borer, K; Bussière, A; Elsener, K; Gorodetzky, P; Guillaud, J P; Hess, P; Kabana, S; Klingenberg, R; Lehmann, G; Lindén, T; Lohmann, K D; Mommsen, R K; Moser, U; Pretzl, Klaus P; Schacher, J; Stoffel, F; Spiwoks, R; Tuominiemi, Jorma; Weber, M; Gorodetzky, Ph.
2001-01-01
The NA52 collaboration searches for a discontinuous behaviour of charged kaons produced in Pb+Pb collisions at 158 A GeV as a function of the impact parameter, which could reveal a hadron to quark-gluon plasma (QGP) phase transition. The K+ yield is found to grow proportional to the number of participating ('wounded') nucleons N, above N=100. Previous NA52 data agree with the above finding and show a discontinuous behaviour in the kaon centrality dependence near N=100, marking the onset of strangeness enhancement -over e.g. p+A data at the same \\sqrt{s}- in a chemically equilibrated phase.
Centrality dependence of K+ produced in Pb+Pb collisions at 158 GeV per nucleon
Arsenescu, R; Borer, K; Kabana, S; Klingenberg, R; Lehmann, G; Mommsen, R K; Moser, U; Pretzl, Klaus P; Schacher, J; Spiwoks, R; Weber, M; Elsener, K; Lohmann, K D; Baglin, C; Bussière, A; Guillaud, J P; Lindén, T; Tuominiemi, Jorma; Gorodetzky, P; Gorodetzky, Ph.
2000-01-01
The NA52 collaboration searches for a discontinuous behaviour of charged kaons produced in Pb+Pb collisions at 158 A GeV as a function of the impact parameter, which could reveal a hadron to quark-gluon plasma (QGP) phase transition. The K+ yield is found to grow proportional to the number of participating ('wounded') nucleons N, above N=100. Previous NA52 data agree with the above finding and show a discontinuous behaviour in the kaon centrality dependence near N=100, marking the onset of strangeness enhancement -over e.g. p+A data at the same \\sqrt{s}- in a chemically equilibrated phase.
Phases of QCD, thermal quasiparticles, and dilepton radiation from a fireball
Renk, Thorsten; Schneider, Roland; Weise, Wolfram
2002-07-01
We calculate dilepton production rates from a fireball adapted to the kinematical conditions realized in ultrarelativistic heavy-ion collisions over a broad range of beam energies. The freeze-out state of the fireball is fixed by hadronic observables. We use this information combined with the initial geometry of the collision region to follow the space-time evolution of the fireball. Assuming entropy conservation, its bulk thermodynamic properties can then be uniquely obtained once the equation of state (EOS) is specified. The high-temperature quark-gluon plasma (QGP) phase is modeled by a nonperturbative quasiparticle model that incorporates a phenomenological confinement description, adapted to lattice QCD results. For the hadronic phase, we interpolate the EOS into the region where a resonance gas approach seems applicable, keeping track of a possible overpopulation of the pion phase space. In this way, the fireball evolution is specified without reference to dilepton data, thus eliminating it as an adjustable parameter in the rate calculations. Dilepton emission in the QGP phase is then calculated within the quasiparticle model. In the hadronic phase, both temperature and finite baryon density effects on the photon spectral function are incorporated. Existing dilepton data from CERES at 158 and 40 A GeV Pb-Au collisions are well described, and a prediction for the PHENIX setup at RHIC for (s)=200A GeV is given.
Microgravity Two-Phase Flow Transition
Parang, M.; Chao, D.
1999-01-01
Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.
PT phase transition in multidimensional quantum systems
Bender, Carl M
2012-01-01
Non-Hermitian PT-symmetric quantum-mechanical Hamiltonians generally exhibit a phase transition that separates two parametric regions, (i) a region of unbroken PT symmetry in which the eigenvalues are all real, and (ii) a region of broken PT symmetry in which some of the eigenvalues are complex. This transition has recently been observed experimentally in a variety of physical systems. Until now, theoretical studies of the PT phase transition have generally been limited to one-dimensional models. Here, four nontrivial coupled PT-symmetric Hamiltonians, $H=p^2/2+x^2/2+q^2/2+y^2/2+igx^2y$, $H=p^2/2+x^2/2+q^2/2+y^2+igx^2y$, $H=p^2/2+x^2/2+q^2/2+y^2/2+r^2/2+z^2/2+igxyz$, and $H=p^2/2+x^2/2+q^2/2+y^2+r^2/2+3z^2/2+igxyz$ are examined. Based on extensive numerical studies, this paper conjectures that all four models exhibit a phase transition. The transitions are found to occur at $g\\approx 0.1$, $g\\approx 0.04$, $g\\approx 0.1$, and $g\\approx 0.05$. These results suggest that the PT phase transition is a robust phen...
The diamagnetic phase transition in Magnetars
Wang, Zhaojun; Zhu, Chunhua; Wu, Baoshan
2016-01-01
Neutron stars are ideal astrophysical laboratories for testing theories of the de Haas-van Alphen (dHvA) effect and diamagnetic phase transition which is associated with magnetic domain formation. The "magnetic interaction" between delocalized magnetic moments of electrons (the Shoenberg effect), can result in an effect of the diamagnetic phase transition into domains of alternating magnetization (Condon's domains). Associated with the domain formation are prominent magnetic field oscillation and anisotropic magnetic stress which may be large enough to fracture the crust of magnetar with a super-strong field. Even if the fracture is impossible as in "low-field" magnetar, the depinning phase transition of domain wall motion driven by low field rate (mainly due to the Hall effect) in the randomly perturbed crust can result in a catastrophically variation of magnetic field. This intermittent motion, similar to the avalanche process, makes the Hall effect be dissipative. These qualitative consequences about magne...
Thermogeometric phase transition in a unified framework
Banerjee, Rabin; Samanta, Saurav
2016-01-01
Using geomterothermodynamics (GTD), we investigate the phase transition of black hole in a metric independent way. We show that for any black hole, curvature scalar (of equilibrium state space geometry) is singular at the point where specific heat diverges. Previously such a result could only be shown by taking specific examples on a case by case basis. A different type of phase transition, where inverse specific heat diverges, is also studied within this framework. We show that in the latter case, metric (of equilibrium state space geometry) is singular instead of curvature scalar. Since a metric singularity may be a coordinate artifact, we propose that GTD indicates that it is the singularity of specific heat and not inverse specific heat which indicates a phase transition of black holes.
Quantum phase transitions with dynamical flavors
Bea, Yago; Ramallo, Alfonso V
2016-01-01
We study the properties of a D6-brane probe in the ABJM background with smeared massless dynamical quarks in the Veneziano limit. Working at zero temperature and non-vanishing charge density, we show that the system undergoes a quantum phase transition in which the topology of the brane embedding changes from a black hole to a Minkowski embedding. In the unflavored background the phase transition is of second order and takes place when the charge density vanishes. We determine the corresponding critical exponents and show that the scaling behavior near the quantum critical point has multiplicative logarithmic corrections. In the background with dynamical quarks the phase transition is of first order and occurs at non-zero charge density. In this case we compute the discontinuity of several physical quantities as functions of the number $N_f$ of unquenched quarks of the background.
Quantum phase transitions with dynamical flavors
Bea, Yago; Jokela, Niko; Ramallo, Alfonso V.
2016-07-01
We study the properties of a D6-brane probe in the Aharony-Bergman-Jafferis-Maldacena (ABJM) background with smeared massless dynamical quarks in the Veneziano limit. Working at zero temperature and nonvanishing charge density, we show that the system undergoes a quantum phase transition in which the topology of the brane embedding changes from a black hole to a Minkowski embedding. In the unflavored background the phase transition is of second order and takes place when the charge density vanishes. We determine the corresponding critical exponents and show that the scaling behavior near the quantum critical point has multiplicative logarithmic corrections. In the background with dynamical quarks the phase transition is of first order and occurs at nonzero charge density. In this case we compute the discontinuity of several physical quantities as functions of the number Nf of unquenched quarks of the background.
Late-time cosmological phase transitions
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))
1990-11-01
It is shown that the potential galaxy formation and large-scale structure problems of objects existing at high redshifts (Z {approx gt} 5), structures existing on scales of 100M pc as well as velocity flows on such scales, and minimal microwave anisotropies ({Delta}T/T) {approx lt} 10{sup {minus}5} can be solved if the seeds needed to generate structure form in a vacuum phase transition after decoupling. It is argued that the basic physics of such a phase transition is no more exotic than that utilized in the more traditional GUT scale phase transitions, and that, just as in the GUT case, significant random gaussian fluctuations and/or topological defects can form. Scale lengths of {approximately}100M pc for large-scale structure as well as {approximately}1 M pc for galaxy formation occur naturally. Possible support for new physics that might be associated with such a late-time transition comes from the preliminary results of the SAGE solar neutrino experiment, implying neutrino flavor mixing with values similar to those required for a late-time transition. It is also noted that a see-saw model for the neutrino masses might also imply a tau neutrino mass that is an ideal hot dark matter candidate. However, in general either hot or cold dark matter can be consistent with a late-time transition. 47 refs., 2 figs.
Queueing phase transition: theory of translation.
Romano, M Carmen; Thiel, Marco; Stansfield, Ian; Grebogi, Celso
2009-05-15
We study the current of particles on a lattice, where to each site a different hopping probability has been associated and the particles can move only in one direction. We show that the queueing of the particles behind a slow site can lead to a first-order phase transition, and derive analytical expressions for the configuration of slow sites for this to happen. We apply this stochastic model to describe the translation of mRNAs. We show that the first-order phase transition, uncovered in this work, is the process responsible for the classification of the proteins having different biological functions.
Exceptional Points and Dynamical Phase Transitions
Directory of Open Access Journals (Sweden)
I. Rotter
2010-01-01
Full Text Available In the framework of non-Hermitian quantum physics, the relation between exceptional points,dynamical phase transitions and the counter intuitive behavior of quantum systems at high level density is considered. The theoretical results obtained for open quantum systems and proven experimentally some years ago on a microwave cavity, may explain environmentally induce deffects (including dynamical phase transitions, which have been observed in various experimental studies. They also agree(qualitatively with the experimental results reported recently in PT symmetric optical lattices.
Phase Transition in Loop Quantum Gravity
Mäkelä, Jarmo
2016-01-01
We point out that with a specific counting of states loop quantum gravity implies that black holes perform a phase transition at a certain characteristic temperature $T_C$. In this phase transition the punctures of the spin network on the stretched horizon of the black hole jump, in effect, from the vacuum to the excited states. The characteristic temperature $T_C$ may be regarded as the lowest possible temperature of the hole. From the point of view of a distant observer at rest with respect to the hole the characteristic temperature $T_C$ corresponds to the Hawking temperature of the hole.
Scaling Concepts in Describing Continuous Phase Transitions
Indian Academy of Sciences (India)
2016-10-01
Phase transitions, like the boiling of water upon increasingtemperature, are a part of everyday experience and are yet,upon closer inspection, unusual phenomena, and reveal a hostof fascinating features. Comprehending key aspects of phasetransitions has lead to the uncovering of new ways of describingmatter composed of large numbers of interacting elements,which form a dominant way of analysis in contemporarystatistical mechanics and much else. An introductorydiscussion is presented here of the concepts of scaling, universalityand renormalization, which forms the foundation ofthe study of continuous phase transitions, such as the spontaneousmagnetization of ferromagnetic substances.
Endpoint of the hot electroweak phase transition
Csikor, Ferenc; Heitger, J
1999-01-01
We give the nonperturbative phase diagram of the four-dimensional hot electroweak phase transition. The Monte-Carlo analysis is done on lattices with different lattice spacings ($a$). A systematic extrapolation $a \\to 0$ is done. Our results show that the finite temperature SU(2)-Higgs phase transition is of first order for Higgs-boson masses $m_H<66.5 \\pm 1.4$ GeV. At this endpoint the phase transition is of second order, whereas above it only a rapid cross-over can be seen. The full four-dimensional result agrees completely with that of the dimensional reduction approximation. This fact is of particular importance, because it indicates that the fermionic sector of the Standard Model can be included perturbatively. We obtain that the Higgs-boson endpoint mass in the Standard Model is $72.4 \\pm 1.7$ GeV. Taking into account the LEP Higgs-boson mass lower bound excludes any electroweak phase transition in the Standard Model.
An Algorithm for Selecting QGP Candidate Events from Relativistic Heavy Ion Collision Data Sample
Lian Shou Liu; Yuan, H B; Lianshou, Liu; Qinghua, Chen; Yuan, Hu
1998-01-01
The formation of quark-gluon plasma (QGP) in relativistic heavy ion collision, is expected to be accompanied by a background of ordinary collision events without phase transition. In this short note an algorithm is proposed to select the QGP candidate events from the whole event sample. This algorithm is based on a simple geometrical consideration together with some ordinary QGP signal, e.g. the increasing of $K/\\pi$ ratio. The efficiency of this algorithm in raising the 'signal/noise ratio' of QGP events in the selected sub-sample is shown explicitly by using Monte-Carlo simulation.
Electromagnetic probes of strongly interacting matter
Indian Academy of Sciences (India)
Jan-E Alam
2015-05-01
The nuclear matter under extreme conditions of temperatures () and baryonic densities () undergoes a phase transition to quark gluon plasma (QGP). It is expected that such extreme conditions can be achieved by colliding nuclei at ultrarelativistic energies. In the present review, the suitability of photons and dileptons as diagnostic tools of QGP has been discussed. The photon and dilepton spectra originating from heavy-ion collisions at LHC energies have been explicitly displayed in this article. Results from SPS and RHIC have been discussed adequately with appropriate references. The role of single electron spectra originating from the decays of heavy flavoured mesons on QGP detection has also been discussed briefly.
Heavy Quark and Quarkonium Transport in High Energy Nuclear Collisions
Energy Technology Data Exchange (ETDEWEB)
Zhou, Kai [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Institute for Theoretical Physics, Johann Wolfgang Goethe-University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany); Dai, Wei [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Xu, Nu [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Zhuang, Pengfei [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China)
2016-12-15
The strong interaction between heavy quarks and the quark gluon plasma makes the open and hidden charm hadrons be sensitive probes of the deconfinement phase transition in high energy nuclear collisions. Both the cold and hot nuclear matter effects change with the colliding energy and significantly influence the heavy quark and charmonium yield and their transverse momentum distributions. The ratio of averaged quarkonium transverse momentum square and the elliptic flow reveal the nature of the QCD medium created in heavy ion collisions at SPS, RHIC and LHC energies.
Overview of quarkonium production in heavy-ion collisions at LHC
Directory of Open Access Journals (Sweden)
Hong Byungsik
2016-01-01
Full Text Available Quarkonium has been regarded as one of the golden probes to identify the phase transition from confined hadronic matter to the deconfined quark-gluon plasma (QGP in heavy-ion collisions. Recent data on the yields and momentum distributions of J/ψ and ϒ families in pp, pPb, and PbPb collisions at the Large Hadron Collider (LHC are reviewed. The possible implications related to the propagation of quarkonia in the deconfined hot, dense matter and the modified parton distribution function (PDF in cold nuclei are also discussed.
Overview of quarkonium production in heavy-ion collisions at LHC
Hong, Byungsik
2016-07-01
Quarkonium has been regarded as one of the golden probes to identify the phase transition from confined hadronic matter to the deconfined quark-gluon plasma (QGP) in heavy-ion collisions. Recent data on the yields and momentum distributions of J/ψ and ϒ families in pp, pPb, and PbPb collisions at the Large Hadron Collider (LHC) are reviewed. The possible implications related to the propagation of quarkonia in the deconfined hot, dense matter and the modified parton distribution function (PDF) in cold nuclei are also discussed.
Srivastava, Brijesh K
2011-01-01
Possible phase transition of strongly interacting matter from hadron to a Quark-Gluon Plasma (QGP) state have in the p ast received considerable interest. It has been suggested that this problem might be treated by percolation theory. Th e Color String Percolation Model (CSPM) is used to determine the equation of state (EOS) of the QGP produced in central Au-Au collisions at RHIC energies. The bulk thermodynamic quantities- energy density, entropy density and t he sound velocity- are obtained in the framework of CSPM. It is shown that the results are in excellent agreement with the recent lattice QCD calculations(LQCD).
Srivastava, Brijesh K.
2011-07-01
Possible phase transition of strongly interacting matter from hadron to a Quark-Gluon Plasma (QGP) state have in the past received considerable interest. It has been suggested that this problem might be treated by percolation theory. The Color String Percolation Model (CSPM) is used to determine the equation of state (EOS) of the QGP produced in central Au-Au collisions at RHIC energies. The bulk thermodynamic quantities - energy density, entropy density and the sound velocity - are obtained in the framework of CSPM. It is shown that the results are in excellent agreement with the recent lattice QCD calculations(LQCD).
Energy Technology Data Exchange (ETDEWEB)
Srivastava, Brijesh K. [Department of Physics, Purdue University, West Lafayette, Indiana (United States)
2011-07-15
Possible phase transition of strongly interacting matter from hadron to a Quark-Gluon Plasma (QGP) state have in the past received considerable interest. It has been suggested that this problem might be treated by percolation theory. The Color String Percolation Model (CSPM) is used to determine the equation of state (EOS) of the QGP produced in central Au-Au collisions at RHIC energies. The bulk thermodynamic quantities - energy density, entropy density and the sound velocity - are obtained in the framework of CSPM. It is shown that the results are in excellent agreement with the recent lattice QCD calculations(LQCD).
Hydrodynamic Flow and Jet Induced Mach Shocks at RHIC and LHC
Stöcker, H; Rau, P; Betz, Barbara; Rau, Philip; St\\"ocker, Horst
2007-01-01
We discuss the present collective flow signals for the phase transition to quark-gluon plasma (QGP) and the collective flow as a barometer for the equation of state (EoS). A study of Mach shocks induced by fast partonic jets propagating through the QGP is given. We predict a significant deformation of Mach shocks in central Au+Au collisions at RHIC and LHC energies as compared to the case of jet propagation in a static medium. Results of a hydrodynamical study of jet energy loss are presented.
Relativistic heavy ion collisions. Final report, May 1, 1993-April 30, 1996
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-07-01
The research program supported by the Nuclear Physics Division of DOE started in May 1991. The present three year period is from May 1, 1993 to April 30, 1996. This progress report summarizes the work done during this period. The main topics covered in this report are: quark-hadron phase transitions; particle production by soft interaction in hadronic and nuclear collisions; quantum chromodynamics; charm production; chaos in non-abelian gauge theory; quark-gluon plasma 2; and comments on training of young physicists.
Transition to turbulence in pipe flow as a phase transition
Vasudevan, Mukund; Hof, Björn
2015-11-01
In pipe flow, turbulence first arises in the form of localized turbulent patches called puffs. The flow undergoes a transition to sustained turbulence via spatio-temporal intermittency, with puffs splitting, decaying and merging in the background laminar flow. However, the due to mean advection of the puffs and the long timescales involved (~107 advective time units), it is not possible to study the transition in typical laboratory set-ups. So far, it has only been possible to indirectly estimate the critical point for the transition. Here, we exploit the stochastic memoryless nature of the puff decay and splitting processes to construct a pipe flow set-up, that is periodic in a statistical sense. It then becomes possible to study the flow for sufficiently long times and characterize the transition in detail. We present measurements of the turbulent fraction as a function of Reynolds number which in turn allows a direct estimate of the critical point. We present evidence that the transition has features of a phase transition of second order.
Deconfinement phase transition in neutron star matter
Institute of Scientific and Technical Information of China (English)
LI Ang; PENG Guang-Xiong; Lombardo U
2009-01-01
The transition from hadron phase to strange quark phase in dense matter is investigated. Instead of using the conventional bag model in quark sect, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates, with a thermodynamic problem improved. In nuclear slot,we adopt the equation of state from Brueckner-Bethe-Goldstone approach with three-body force. It is found that the mixed phase can occur, for reasonable confinement parameter, near the normal saturation density,and transit to pure quark matter at 4-5 times the saturation, which is quite different from the previous results from other quark models that pure quark phase can not appear at neutron-star densities.
Liquid gas phase transition in hypernuclei
Mallik, S
2016-01-01
The fragmentation of excited hypernuclear system formed in heavy ion collisions has been described by the canonical thermodynamical model extended to three component systems. The multiplicity distribution of the fragments has been analyzed in detail and it has been observed that the hyperons have the tendency to get attached to the heavier fragments. Another important observation is the phase coexistence of the hyperons, a phenomenon which is linked to liquid gas phase transition in strange matter.
Passive Supporters of Terrorism and Phase Transitions
August, Friedrich; Delitzscher, Sascha; Hiller, Gerald; Krueger, Tyll
2010-01-01
We discuss some social contagion processes to describe the formation and spread of radical opinions. The dynamics of opinion spread involves local threshold processes as well as mean field effects. We calculate and observe phase transitions in the dynamical variables resulting in a rapidly increasing number of passive supporters. This strongly indicates that military solutions are inappropriate.
Hysteresis in the phase transition of chocolate
Ren, Ruilong; Lu, Qunfeng; Lin, Sihua; Dong, Xiaoyan; Fu, Hao; Wu, Shaoyi; Wu, Minghe; Teng, Baohua
2016-01-01
We designed an experiment to reproduce the hysteresis phenomenon of chocolate appearing in the heating and cooling process, and then established a model to relate the solidification degree to the order parameter. Based on the Landau-Devonshire theory, our model gave a description of the hysteresis phenomenon in chocolate, which lays the foundations for the study of the phase transition behavior of chocolate.
Caloric materials near ferroic phase transitions
Moya, X.; Kar-Narayan, S.; Mathur, N. D.
2014-05-01
A magnetically, electrically or mechanically responsive material can undergo significant thermal changes near a ferroic phase transition when its order parameter is modified by the conjugate applied field. The resulting magnetocaloric, electrocaloric and mechanocaloric (elastocaloric or barocaloric) effects are compared here in terms of history, experimental method, performance and prospective cooling applications.
Neutrino Oscillation Induced by Chiral Phase Transition
Institute of Scientific and Technical Information of China (English)
MU Cheng-Fu; SUN Gao-Feng; ZHUANG Peng-Fei
2009-01-01
Electric charge neutrality provides a relationship between chiral dynamics and neutrino propagation in compact stars.Due to the sudden drop of the electron density at the first-order chiral phase transition,the oscillation for low energy neutrinos is significant and can be regarded as a signature of chiral symmetry restoration in the core of compact stars.
Higgs Couplings and Electroweak Phase Transition
Katz, Andrey
2014-01-01
We argue that extensions of the Standard Model (SM) with a strongly first-order electroweak phase transition generically predict significant deviations of the Higgs couplings to gluons, photons, and Z bosons from their SM values. Precise experimental measurements of the Higgs couplings at the LHC and at the proposed next-generation facilities will allow for a robust test of the phase transition dynamics. To illustrate this point, in this paper we focus on the scenario in which loops of a new scalar field are responsible for the first-order phase transition, and study a selection of benchmark models with various SM gauge quantum numbers of the new scalar. We find that the current LHC measurement of the Higgs coupling to gluons already excludes the possibility of a first-order phase transition induced by a scalar in a sextet, or larger, representation of the SU(3)_c. Future LHC experiments (including HL-LHC) will be able to definitively probe the case when the new scalar is a color triplet. If the new scalar is...
Chaos: Butterflies also Generate Phase Transitions
Leplaideur, Renaud
2015-10-01
We exhibit examples of mixing subshifts of finite type and of continuous potentials such that there are phase transitions but the pressure is always strictly convex. More surprisingly, we show that the pressure can be analytic on some interval although there exist several equilibrium states.
Phase Transitions, Diffraction Studies and Marginal Dimensionality
DEFF Research Database (Denmark)
Als-Nielsen, Jens Aage
1985-01-01
Continuous phase transitions and the associated critical phenomena have been one of the most active areas of research in condensed matter physics for several decades. This short review is only one cut through this huge subject and the author has chosen to emphasize diffraction studies as a basic...
Problem of phase transitions in nuclear structure
Energy Technology Data Exchange (ETDEWEB)
Scharff-Goldhaber, G
1980-01-01
Phase transitions between rotational and vibrational nuclei are discussed from the point of view of the variable moment of inertia model. A three-dimensional plot of the ground-state moments of inertia of even-even nuclei vs N and Z is shown. 3 figures. (RWR)
The Structural Phase Transition in Octaflournaphtalene
DEFF Research Database (Denmark)
Mackenzie, Gordon A.; Arthur, J. W.; Pawley, G. S.
1977-01-01
The phase transition in octafluoronaphthalene has been investigated by Raman scattering and neutron powder diffraction. The weight of the experimental evidence points to a unit cell doubling in the a direction, but with no change in space group symmetry. Lattice dynamics calculations support...
Dimensional phase transitions in small Yukawa clusters
Sheridan, T E
2009-01-01
We investigate the one- to two-dimensional zigzag transition in clusters consisting of a small number of particles interacting through a Yukawa (Debye) potential and confined in a two-dimensional biharmonic potential well. Dusty (complex) plasma clusters with $n \\le 19$ monodisperse particles are characterized experimentally for two different confining wells. The well anisotropy is accurately measured, and the Debye shielding parameter is determined from the longitudinal breathing frequency. Debye shielding is shown to be important. A model for this system is used to predict equilibrium particle configurations. The experiment and model exhibit excellent agreement. The critical value of $n$ for the zigzag transition is found to be less than that predicted for an unshielded Coulomb interaction. The zigzag transition is shown to behave as a continuous phase transition from a one-dimensional to a two-dimensional state, where the state variables are the number of particles, the well anisotropy and the Debye shield...
Phase transition to QGP matter : confined vs deconfined matter
Maire, Antonin
2015-01-01
Simplified phase diagram of the nuclear phase transition, from the regular hadronic matter to the QGP phase. The sketch is meant to describe the transition foreseen along the temperature axis, at low baryochemical potential, µB.
Phase transition – Break down the walls
DEFF Research Database (Denmark)
Wandahl, Søren
2012-01-01
-phase issues of the construction process. This research first identifies the problems theoretically, and looks into which framework to be used in understanding of the phase transition problem. This combined with data from interviews reveal 8 major issues in phase transition, which decrease the value....... In a popular term this problem is often called “over the wall syndrome”. The manufacturing industry has worked with this for many years, in e.g. integrated product development, concurrent engineering, supply chain management, etc. Now the construction industry needs to focus more on these crucial inter...... tender often is limited due to regulations. Therefore, contractors miss a large amount of non-operational information, and the client and his consulting engineers never mange to share their tacit knowledge of project preconditions....
Phase transitions in Pareto optimal complex networks
Seoane, Luís F
2015-01-01
The organization of interactions in complex systems can be described by networks connecting different units. These graphs are useful representations of the local and global complexity of the underlying systems. The origin of their topological structure can be diverse, resulting from different mechanisms including multiplicative processes and optimization. In spatial networks or in graphs where cost constraints are at work, as it occurs in a plethora of situations from power grids to the wiring of neurons in the brain, optimization plays an important part in shaping their organization. In this paper we study network designs resulting from a Pareto optimization process, where different simultaneous constraints are the targets of selection. We analyze three variations on a problem finding phase transitions of different kinds. Distinct phases are associated to different arrangements of the connections; but the need of drastic topological changes does not determine the presence, nor the nature of the phase transit...
A possible evidence of observation of two mixed phases in nuclear collisions
Bugaev, K A; Sagun, V V; Zinovjev, G M; Oliinychenko, D R; Trubnikov, V S; Nikonov, E G
2015-01-01
Using an advanced version of the hadron resonance gas model we have found several remarkable irregularities at chemical freeze-out. The most prominent of them are two sets of highly correlated quasi-plateaus in the collision energy dependence of the entropy per baryon, total pion number per baryon, and thermal pion number per baryon which we found at center of mass energies 3.6-4.9 GeV and 7.6-10 GeV. The low energy set of quasi-plateaus was predicted a long time ago. On the basis of the generalized shock-adiabat model we demonstrate that the low energy correlated quasi-plateaus give evidence for the anomalous thermodynamic properties of the mixed phase at its boundary to the quark-gluon plasma. The question is whether the high energy correlated quasi-plateaus are also related to some kind of mixed phase. In order to answer this question we employ the results of a systematic meta-analysis of the quality of data description of 10 existing event generators of nucleus-nucleus collisions in the range of center of...
Phase diagrams and kinetics of phase transitions in protein solutions.
Vekilov, Peter G
2012-05-16
The phase behavior of proteins is of interest for fundamental and practical reasons. The nucleation of new phases is one of the last major unresolved problems of nature. The formation of protein condensed phases (crystals, polymers, and other solid aggregates, as well as dense liquids and gels) underlies pathological conditions, plays a crucial role in the biological function of the respective protein, or is an essential part of laboratory and industrial processes. In this review, we focus on phase transitions of proteins in their properly folded state. We first summarize the recently acquired understanding of physical processes underlying the phase diagrams of the protein solutions and the thermodynamics of protein phase transitions. Then we review recent findings on the kinetics of nucleation of dense liquid droplets and crystals. We explore the transition from nucleation to spinodal decomposition for liquid-liquid separation and introduce the new concept of solution-to-crystal spinodal. We review the two-step mechanism of protein crystal nucleation, in which mesoscopic metastable protein clusters serve as precursors to the ordered crystal nuclei. The concepts and mechanisms reviewed here provide powerful tools for control of the nucleation process by varying the solution thermodynamic parameters.
The comfortable driving model revisited: Traffic phases and phase transitions
Knorr, Florian
2013-01-01
We study the spatiotemporal patterns resulting from different boundary conditions for a microscopic traffic model and contrast it with empirical results. By evaluating the time series of local measurements, the local traffic states are assigned to the different traffic phases of Kerner's three-phase traffic theory. For this classification we use the rule-based FOTO-method, which provides `hard' rules for this assignment. Using this approach, our analysis shows that the model is indeed able to reproduce three qualitatively different traffic phases: free flow (F), synchronized traffic (S), and wide moving jams (J). In addition, we investigate the likelihood of transitions between the three traffic phases. We show that a transition from free flow (F) to a wide moving jam (J) often involves an intermediate transition; first from free flow F to synchronized flow S and then from synchronized flow to a wide moving jam. This is supported by the fact that the so called F->S transition (from free flow to synchronized t...
Dynamics of the chiral phase transition
van Hees, H; Meistrenko, A; Greiner, C
2013-01-01
The intention of this study is the search for signatures of the chiral phase transition in heavy-ion collisions. To investigate the impact of fluctuations, e.g., of the baryon number, at the transition or at a critical point, the linear sigma model is treated in a dynamical (3+1)-dimensional numerical simulation. Chiral fields are approximated as classical mean fields, and quarks are described as quasi particles in a Vlasov equation. Additional dynamics is implemented by quark-quark and quark-sigma-field interactions. For a consistent description of field-particle interactions, a new Monte-Carlo-Langevin-like formalism has been developed and is discussed.
Phase transitions in Pareto optimal complex networks.
Seoane, Luís F; Solé, Ricard
2015-09-01
The organization of interactions in complex systems can be described by networks connecting different units. These graphs are useful representations of the local and global complexity of the underlying systems. The origin of their topological structure can be diverse, resulting from different mechanisms including multiplicative processes and optimization. In spatial networks or in graphs where cost constraints are at work, as it occurs in a plethora of situations from power grids to the wiring of neurons in the brain, optimization plays an important part in shaping their organization. In this paper we study network designs resulting from a Pareto optimization process, where different simultaneous constraints are the targets of selection. We analyze three variations on a problem, finding phase transitions of different kinds. Distinct phases are associated with different arrangements of the connections, but the need of drastic topological changes does not determine the presence or the nature of the phase transitions encountered. Instead, the functions under optimization do play a determinant role. This reinforces the view that phase transitions do not arise from intrinsic properties of a system alone, but from the interplay of that system with its external constraints.
The Next Generation Transit Survey - Prototyping Phase
McCormac, James; Wheatley, Peter; West, Richard; Walker, Simon; Bento, Joao; Skillen, Ian; Faedi, Francesca; Burleigh, Matt; Casewell, Sarah; Chazelas, Bruno; Genolet, Ludovic; Gibson, Neale; Goad, Mike; Lawrie, Katherine; Ryans, Robert; Todd, Ian; Udry, Stephan; Watson, Christopher
2016-01-01
We present the prototype telescope for the Next Generation Transit Survey, which was built in the UK in 2008/09 and tested on La Palma in the Canary Islands in 2010. The goals for the prototype system were severalfold: to determine the level of systematic noise in an NGTS-like system; demonstrate that we can perform photometry at the (sub) millimagnitude level on transit timescales across a wide field; show that it is possible to detect transiting super-Earth and Neptune-sized exoplanets and prove the technical feasibility of the proposed planet survey. We tested the system for around 100 nights and met each of the goals above. Several key areas for improvement were highlighted during the prototyping phase. They have been subsequently addressed in the final NGTS facility which was recently commissioned at ESO Cerro Paranal, Chile.
Holographic phase transitions at finite chemical potential
Mateos, David; Matsuura, Shunji; Myers, Robert C.; Thomson, Rowan M.
2007-11-01
Recently, holographic techniques have been used to study the thermal properties of Script N = 2 super-Yang-Mills theory, with gauge group SU(Nc) and coupled to Nf coupling. Here we consider the phase diagram as a function of temperature and baryon chemical potential μb. For fixed μb transitions separating a region with vanishing baryon density and one with nonzero density. For fixed μb>Nc Mq there is no phase transition as a function of the temperature and the baryon density is always nonzero. We also compare the present results for the grand canonical ensemble with those for canonical ensemble in which the baryon density is held fixed [1].
Nonequilibrium phase transitions in biomolecular signal transduction
Smith, Eric; Krishnamurthy, Supriya; Fontana, Walter; Krakauer, David
2011-11-01
We study a mechanism for reliable switching in biomolecular signal-transduction cascades. Steady bistable states are created by system-size cooperative effects in populations of proteins, in spite of the fact that the phosphorylation-state transitions of any molecule, by means of which the switch is implemented, are highly stochastic. The emergence of switching is a nonequilibrium phase transition in an energetically driven, dissipative system described by a master equation. We use operator and functional integral methods from reaction-diffusion theory to solve for the phase structure, noise spectrum, and escape trajectories and first-passage times of a class of minimal models of switches, showing how all critical properties for switch behavior can be computed within a unified framework.
A nonequilibrium phase transition in immune response
Institute of Scientific and Technical Information of China (English)
Zhang Wei; Qi An-Shen
2004-01-01
The dynamics of immune response correlated to signal transduction in immune thymic cells (T cells) is studied.In particular, the problem of the phosphorylation of the immune-receptor tyrosine-based activation motifs (ITAM) is explored. A nonlinear model is established on the basis of experimental observations. The behaviours of the model can be well analysed using the concepts of nonequilibrium phase transitions. In addition, the Riemann-Hugoniot cusp catastrophe is demonstrated by the model. Due to the application of the theory of nonequilibrium phase transitions,the biological phenomena can be clarified more precisely. The results can also be used to further explain the signal transduction and signal discrimination of an important type of immune T cell.
Phase transition in the countdown problem
Lacasa, Lucas; Luque, Bartolo
2012-07-01
We present a combinatorial decision problem, inspired by the celebrated quiz show called Countdown, that involves the computation of a given target number T from a set of k randomly chosen integers along with a set of arithmetic operations. We find that the probability of winning the game evidences a threshold phenomenon that can be understood in the terms of an algorithmic phase transition as a function of the set size k. Numerical simulations show that such probability sharply transitions from zero to one at some critical value of the control parameter, hence separating the algorithm's parameter space in different phases. We also find that the system is maximally efficient close to the critical point. We derive analytical expressions that match the numerical results for finite size and permit us to extrapolate the behavior in the thermodynamic limit.
Structural phase transitions in monolayer molybdenum dichalcogenides
Choe, Duk-Hyun; Sung, Ha June; Chang, Kee Joo
2015-03-01
The recent discovery of two-dimensional materials such as graphene and transition metal dichalcogenides (TMDs) has provided opportunities to develop ultimate thin channel devices. In contrast to graphene, the existence of moderate band gap and strong spin-orbit coupling gives rise to exotic electronic properties which vary with layer thickness, lattice structure, and symmetry. TMDs commonly appear in two structures with distinct symmetries, trigonal prismatic 2H and octahedral 1T phases which are semiconducting and metallic, respectively. In this work, we investigate the structural and electronic properties of monolayer molybdenum dichalcogenides (MoX2, where X = S, Se, Te) through first-principles density functional calculations. We find a tendency that the semiconducting 2H phase is more stable than the metallic 1T phase. We show that a spontaneous symmetry breaking of 1T phase leads to various distorted octahedral (1T') phases, thus inducing a metal-to-semiconductor transition. We discuss the effects of carrier doping on the structural stability and the modification of the electronic structure. This work was supported by the National Research Foundation of Korea (NRF) under Grant No. NRF-2005-0093845 and Samsung Science and Technology Foundation under Grant No. SSTFBA1401-08.
Dimension Changing Phase Transitions in Instanton Crystals
Kaplunovsky, Vadim
2013-01-01
We investigate lattices of instantons and the dimension-changing transitions between them. Our ultimate goal is the 3d->4D transition, which is holographically dual to the phase transition between the baryonic and the quarkyonic phases of cold nuclear matter. However, in this paper (just as in [1]) we focus on lower dimensions -- the 1D lattice of instantons in a harmonic potential V M_2^2x_2^2+M_3^2x_2^2+M_4^2x_4^2 and the zigzag-shaped lattice as a first stage of the 1D->2D transition. We prove that in the low- and moderate-density regimes, interactions between the instantons are dominated by two-body forces. This drastically simplifies finding the ground state of the instantons' orientations, so we made a numeric scan of the whole orientation space instead of assuming any particular ansatz. We find that depending on the M_2/M_3/M_4 ratios, the ground state of instanton orientations can follow a wide variety of patterns. For the straight 1D lattices, we found orientations periodically running over elements ...
Extracellular ice phase transitions in insects.
Hawes, T C
2014-01-01
At temperatures below their temperature of crystallization (Tc), the extracellular body fluids of insects undergo a phase transition from liquid to solid. Insects that survive the transition to equilibrium (complete freezing of the body fluids) are designated as freeze tolerant. Although this phenomenon has been reported and described in many Insecta, current nomenclature and theory does not clearly delineate between the process of transition (freezing) and the final solid phase itself (the frozen state). Thus freeze tolerant insects are currently, by convention, described in terms of the temperature at which the crystallization of their body fluids is initiated, Tc. In fact, the correct descriptor for insects that tolerate freezing is the temperature of equilibrium freezing, Tef. The process of freezing is itself a separate physical event with unique physiological stresses that are associated with ice growth. Correspondingly there are a number of insects whose physiological cryo-limits are very specifically delineated by this transitional envelope. The distinction also has considerable significance for our understanding of insect cryobiology: firstly, because the ability to manage endogenous ice growth is a fundamental segregator of cryotype; and secondly, because our understanding of internal ice management is still largely nascent.
The Hot QCD White Paper: Exploring the Phases of QCD at RHIC and the LHC
Akiba, Yasuyuki; Caines, Helen; Frawley, Anthony; Heinz, Ulrich; Jacak, Barbara; Jia, Jiangyong; Lappi, Tuomas; Li, Wei; Majumder, Abhijit; Morrison, David; Ploskon, Mateusz; Putschke, Joern; Rajagopal, Krishna; Rapp, Ralf; Roland, Gunther; Sorensen, Paul; Wiedemann, Urs; Xu, Nu; Zajc, W A
2015-01-01
The past decade has seen huge advances in experimental measurements made in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and more recently at the Large Hadron Collider (LHC). These new data, in combination with theoretical advances from calculations made in a variety of frameworks, have led to a broad and deep knowledge of the properties of thermal QCD matter. Increasingly quantitative descriptions of the quark-gluon plasma (QGP) created in these collisions have established that the QGP is a strongly coupled liquid with the lowest value of specific viscosity ever measured. However, much remains to be learned about the precise nature of the initial state from which this liquid forms, how its properties vary across its phase diagram and how, at a microscopic level, the collective properties of this liquid emerge from the interactions among the individual quarks and gluons that must be visible if the liquid is probed with sufficiently high resolution. This white paper, prepared by the Hot Q...
Holographic phase transitions at finite chemical potential
Mateos, David; Myers, Robert C; Thomson, Rowan M
2007-01-01
Recently holographic techniques have been used to study the thermal properties of N=2 SYM theory, with gauge group SU(Nc) and coupled to Nf Nc Mq there is no phase transition as a function of the temperature and the baryon density is always nonzero. We also compare the present results for the grand canonical ensemble with those for canonical ensemble in which the baryon density is held fixed [1].
Quantum phase transitions in constrained Bose systems
Bonnes, Lars
2011-01-01
This doctoral thesis studies low dimensional quantum systems that can be realized in recent cold atom experiments. From the viewpoint of quantum statistical mechanics, the main emphasis is on the detailed study of the different quantum and thermal phases and their transitions using numerical methods, such as quantum Monte Carlo and the Tensor Network Renormalization Group. The first part of this work deals with a lattice Boson model subject to strong three-body losses. In a quantum-Zeno li...
Recent theoretical advances on superradiant phase transitions
Baksic, Alexandre; Nataf, Pierre; Ciuti, Cristiano
2013-03-01
The Dicke model describing a single-mode boson field coupled to two-level systems is an important paradigm in quantum optics. In particular, the physics of ``superradiant phase transitions'' in the ultrastrong coupling regime is the subject of a vigorous research activity in both cavity and circuit QED. Recently, we explored the rich physics of two interesting generalizations of the Dicke model: (i) A model describing the coupling of a boson mode to two independent chains A and B of two-level systems, where chain A is coupled to one quadrature of the boson field and chain B to the orthogonal quadrature. This original model leads to a quantum phase transition with a double symmetry breaking and a fourfold ground state degeneracy. (ii) A generalized Dicke model with three-level systems including the diamagnetic term. In contrast to the case of two-level atoms for which no-go theorems exist, in the case of three-level system we prove that the Thomas-Reich-Kuhn sum rule does not always prevent a superradiant phase transition.
Dynamical quantum phase transitions (Review Article)
Zvyagin, A. A.
2016-11-01
During recent years the interest to dynamics of quantum systems has grown considerably. Quantum many body systems out of equilibrium often manifest behavior, different from the one predicted by standard statistical mechanics and thermodynamics in equilibrium. Since the dynamics of a many-body quantum system typically involve many excited eigenstates, with a non-thermal distribution, the time evolution of such a system provides an unique way for investigation of non-equilibrium quantum statistical mechanics. Last decade such new subjects like quantum quenches, thermalization, pre-thermalization, equilibration, generalized Gibbs ensemble, etc. are among the most attractive topics of investigation in modern quantum physics. One of the most interesting themes in the study of dynamics of quantum many-body systems out of equilibrium is connected with the recently proposed important concept of dynamical quantum phase transitions. During the last few years a great progress has been achieved in studying of those singularities in the time dependence of characteristics of quantum mechanical systems, in particular, in understanding how the quantum critical points of equilibrium thermodynamics affect their dynamical properties. Dynamical quantum phase transitions reveal universality, scaling, connection to the topology, and many other interesting features. Here we review the recent achievements of this quickly developing part of low-temperature quantum physics. The study of dynamical quantum phase transitions is especially important in context of their connection to the problem of the modern theory of quantum information, where namely non-equilibrium dynamics of many-body quantum system plays the major role.
Superconducting phase transition in STM tips
Energy Technology Data Exchange (ETDEWEB)
Eltschka, Matthias; Jaeck, Berthold; Assig, Maximilian; Etzkorn, Markus; Ast, Christian R. [Max Planck Institute for Solid State Research, Stuttgart (Germany); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); Ecole Polytechnique Federale de Lausanne (Switzerland)
2015-07-01
The superconducting properties of systems with dimensions comparable to the London penetration depth considerably differ from macroscopic systems. We have studied the superconducting phase transition of vanadium STM tips in external magnetic fields. Employing Maki's theory we extract the superconducting parameters such as the gap or the Zeeman splitting from differential conductance spectra. While the Zeeman splitting follows the theoretical description of a system with s=1/2 and g=2, the superconducting gaps as well as the critical fields depend on the specific tip. For a better understanding of the experimental results, we solve a one dimensional Usadel equation modeling the superconducting tip as a cone with the opening angle α in an external magnetic field. We find that only a small region at the apex of the tip is superconducting in high magnetic fields and that the order of the phase transition is directly determined by α. Further, the spectral broadening increases with α indicating an intrinsic broadening mechanism due to the conical shape of the tip. Comparing these calculations to our experimental results reveals the order of the superconducting phase transition of the STM tips.
Phase transitions of ε-HNIW in compound systems
Directory of Open Access Journals (Sweden)
Jing-yuan Zhang
2016-05-01
Full Text Available The heat-induced phase transitions of ε-HNIW, both neat and coated with various additives used in plastic bonded explosives, were investigated using powder X-ray diffraction and differential scanning calorimetry. It was found that ε-HNIW, after being held at 70°C for 60h, remained in the ε-phase. Applying other conditions, various phase transition parameters were determined, including Tc (the critical phase transition temperature, T50 (the temperature at which 50% of the phase transition is complete and T180 (the percentage of γ-HNIW present in samples heated to 180°C. According to the above three parameters, additives were divided into three categories: those that delay phase transition, those that raise the critical temperature and the transition rate, and those that promote the phase transition. Based on the above data, a phase transition mechanism is proposed.
Stability and Existence of Multidimensional Subsonic Phase Transitions
Institute of Scientific and Technical Information of China (English)
Ya-Guang Wang; Zhouping Xin
2003-01-01
The purpose of this paper is to prove the uniform stability of multidimensional subsonic phase transitions satisfying the viscosity-capillarity criterion in a van der Waals fluid, and further to establish the local existence of phase transition solutions.
Holography and the Electroweak Phase Transition
Creminelli, P; Rattazzi, Riccardo; Creminelli, Paolo; Nicolis, Alberto; Rattazzi, Riccardo
2002-01-01
We study through holography the compact Randall-Sundrum (RS) model at finite temperature. In the presence of radius stabilization, the system is described at low enough temperature by the RS solution. At high temperature it is described by the AdS-Schwarzshild solution with an event horizon replacing the TeV brane. We calculate the transition temperature T_c between the two phases and we find it to be somewhat smaller than the TeV scale. Assuming that the Universe starts out at T >> T_c and cools down by expansion, we study the rate of the transition to the RS phase. We find that the transition is too slow and the Universe ends up in an old inflation scenario unless tight bounds are satisfied by the model parameters. In particular we find that the AdS curvature must be comparable to the 5D Planck mass and that the radius stabilization mechanism must lead to a sizeable distortion of the basic RS metric.
Second-order phase transitions of pure substances
Schaftenaar, H.P.C.
2009-01-01
In this report we are dealing with the thermodynamic theory of second-order phase transitions or continuous transitions of unary systems. The first classification of these phase transitions is due to Ehrenfest (1933), based on chemical potentials. First-order transitions are changes in which the der
Landau Theory in the Region of First Order Phase Transitions
Directory of Open Access Journals (Sweden)
O.G. Medvedovskaya
2014-04-01
Full Text Available For the case when the line of the first order phase transitions does not transform into the line of the second order phase transitions, i.e. not as ends with the tricritical point but not with a critical one: critical lines, limiting the region of metastable states, by using the Landau theory of phase transitions were determined.
Scale invariance from phase transitions to turbulence
Lesne, Annick
2012-01-01
During a century, from the Van der Waals mean field description (1874) of gases to the introduction of renormalization group (RG techniques 1970), thermodynamics and statistical physics were just unable to account for the incredible universality which was observed in numerous critical phenomena. The great success of RG techniques is not only to solve perfectly this challenge of critical behaviour in thermal transitions but to introduce extremely useful tools in a wide field of daily situations where a system exhibits scale invariance. The introduction of scaling, scale invariance and universality concepts has been a significant turn in modern physics and more generally in natural sciences. Since then, a new "physics of scaling laws and critical exponents", rooted in scaling approaches, allows quantitative descriptions of numerous phenomena, ranging from phase transitions to earthquakes, polymer conformations, heartbeat rhythm, diffusion, interface growth and roughening, DNA sequence, dynamical systems, chaos ...
Locating phase transitions in computationally hard problems
Indian Academy of Sciences (India)
B Ashok; T K Patra
2010-09-01
We discuss how phase-transitions may be detected in computationally hard problems in the context of anytime algorithms. Treating the computational time, value and utility functions involved in the search results in analogy with quantities in statistical physics, we indicate how the onset of a computationally hard regime can be detected and the transit to higher quality solutions be quantified by an appropriate response function. The existence of a dynamical critical exponent is shown, enabling one to predict the onset of critical slowing down, rather than finding it after the event, in the specific case of a travelling salesman problem (TSP). This can be used as a means of improving efficiency and speed in searches, and avoiding needless computations.
Phase transition in SONFIS&SORST
Owladeghaffari, Hamed
2008-01-01
In this study, we introduce general frame of MAny Connected Intelligent Particles Systems (MACIPS). Connections and interconnections between particles get a complex behavior of such merely simple system (system in system).Contribution of natural computing, under information granulation theory, are the main topics of this spacious skeleton. Upon this clue, we organize two algorithms involved a few prominent intelligent computing and approximate reasoning methods: self organizing feature map (SOM), Neuro- Fuzzy Inference System and Rough Set Theory (RST). Over this, we show how our algorithms can be taken as a linkage of government-society interaction, where government catches various fashions of behavior: solid (absolute) or flexible. So, transition of such society, by changing of connectivity parameters (noise) from order to disorder is inferred. Add to this, one may find an indirect mapping among finical systems and eventual market fluctuations with MACIPS. Keywords: phase transition, SONFIS, SORST, many con...
Dynamical phase transitions in quantum mechanics
Directory of Open Access Journals (Sweden)
Rotter Ingrid
2012-02-01
Full Text Available The nucleus is described as an open many-body quantum system with a non-Hermitian Hamilton operator the eigenvalues of which are complex, in general. The eigenvalues may cross in the complex plane (exceptional points, the phases of the eigenfunctions are not rigid in approaching the crossing points and the widths bifurcate. By varying only one parameter, the eigenvalue trajectories usually avoid crossing and width bifurcation occurs at the critical value of avoided crossing. An analog spectroscopic redistribution takes place for discrete states below the particle decay threshold. By this means, a dynamical phase transition occurs in the many-level system starting at a critical value of the level density. Hence the properties of the low-lying nuclear states (described well by the shell model and those of highly excited nuclear states (described by random ensembles differ fundamentally from one another. The statement of Niels Bohr on the collective features of compound nucleus states at high level density is therefore not in contradiction to the shell-model description of nuclear (and atomic states at low level density. Dynamical phase transitions are observed experimentally in different quantum mechanical systems by varying one or two parameters.
Phases and phase transitions in the algebraic microscopic shell model
Directory of Open Access Journals (Sweden)
Georgieva A. I.
2016-01-01
Full Text Available We explore the dynamical symmetries of the shell model number conserving algebra, which define three types of pairing and quadrupole phases, with the aim to obtain the prevailing phase or phase transition for the real nuclear systems in a single shell. This is achieved by establishing a correspondence between each of the pairing bases with the Elliott’s SU(3 basis that describes collective rotation of nuclear systems. This allows for a complete classification of the basis states of different number of particles in all the limiting cases. The probability distribution of the SU(3 basis states within theirs corresponding pairing states is also obtained. The relative strengths of dynamically symmetric quadrupole-quadrupole interaction in respect to the isoscalar, isovector and total pairing interactions define a control parameter, which estimates the importance of each term of the Hamiltonian in the correct reproduction of the experimental data for the considered nuclei.
Chiral phase transition from string theory.
Parnachev, Andrei; Sahakyan, David A
2006-09-15
The low energy dynamics of a certain D-brane configuration in string theory is described at weak t'Hooft coupling by a nonlocal version of the Nambu-Jona-Lasinio model. We study this system at finite temperature and strong t'Hooft coupling, using the string theory dual. We show that for sufficiently low temperatures chiral symmetry is broken, while for temperatures larger then the critical value, it gets restored. We compute the latent heat and observe that the phase transition is of the first order.
Melonic phase transition in group field theory
Baratin, Aristide; Oriti, Daniele; Ryan, James P; Smerlak, Matteo
2013-01-01
Group field theories have recently been shown to admit a 1/N expansion dominated by so-called `melonic graphs', dual to triangulated spheres. In this note, we deepen the analysis of this melonic sector. We obtain a combinatorial formula for the melonic amplitudes in terms of a graph polynomial related to a higher dimensional generalization of the Kirchhoff tree-matrix theorem. Simple bounds on these amplitudes show the existence of a phase transition driven by melonic interaction processes. We restrict our study to the Boulatov-Ooguri models, which describe topological BF theories and are the basis for the construction of four dimensional models of quantum gravity.
Detonations and deflagrations in cosmological phase transitions
Megevand, Ariel
2009-01-01
We study the steady state motion of bubble walls in cosmological phase transitions. Taking into account the boundary and continuity conditions for the fluid variables, we calculate numerically the wall velocity as a function of the nucleation temperature, the latent heat, and a friction parameter. We determine regions in the space of these parameters in which detonations and/or deflagrations are allowed. In order to apply the results to a physical case, we calculate these quantities in a specific model, which consists of an extension of the Standard Model with singlet scalar fields. We also obtain analytic approximations for deflagrations and detonations.
Observables of non-equilibrium phase transition
Tomasik, Boris; Melo, Ivan; Kopecna, Renata
2015-01-01
Rapidly expanding fireball which undergoes first-order phase transition will supercool and proceed via spinodal decomposition. Hadrons are produced from the individual fragments as well as leftover matter filling the space between them. Emission from fragments should be visible in rapidity correlations, particularly of protons. Also, even within narrow centrality classes, rapidity distributions will be fluctuating from one event to another in case of fragmentation. This can be identified with the help of Kolmogorov-Smirnov test. Finally, a method is presented which allows to sort events with varying rapidity distributions in such a way, that events with similar rapidity histograms are grouped together.
Early Work on Defect Driven Phase Transitions
Kosterlitz, J. Michael; Thouless, David J.
2016-12-01
This article summarizes the early history of the theory of phase transitions driven by topological defects, such as vortices in superfluid helium films or dislocations and disclinations in two-dimensional solids. We start with a review of our two earliest papers, pointing out their errors and omissions as well as their insights. We then describe the work, partly done by Kosterlitz but mostly done by other people, which corrected these oversights, and applied these ideas to experimental systems, and to numerical and experimental simulations.
Berry phase transition in twisted bilayer graphene
Rode, Johannes C.; Smirnov, Dmitri; Schmidt, Hennrik; Haug, Rolf J.
2016-09-01
The electronic dispersion of a graphene bilayer is highly dependent on rotational mismatch between layers and can be further manipulated by electrical gating. This allows for an unprecedented control over electronic properties and opens up the possibility of flexible band structure engineering. Here we present novel magnetotransport data in a twisted bilayer, crossing the energetic border between decoupled monolayers and coupled bilayer. In addition a transition in Berry phase between π and 2π is observed at intermediate magnetic fields. Analysis of Fermi velocities and gate induced charge carrier densities suggests an important role of strong layer asymmetry for the observed phenomena.
Adiabatic quantum computation and quantum phase transitions
Latorre, J I; Latorre, Jose Ignacio; Orus, Roman
2003-01-01
We analyze the ground state entanglement in a quantum adiabatic evolution algorithm designed to solve the NP-complete Exact Cover problem. The entropy of entanglement seems to obey linear and universal scaling at the point where the mass gap becomes small, suggesting that the system passes near a quantum phase transition. Such a large scaling of entanglement suggests that the effective connectivity of the system diverges as the number of qubits goes to infinity and that this algorithm cannot be efficiently simulated by classical means. On the other hand, entanglement in Grover's algorithm is bounded by a constant.
Phase transition equilibrium of terthiophene isomers
Energy Technology Data Exchange (ETDEWEB)
Costa, Jose C.S.; Lima, Carlos F.R.A.C.; Rocha, Marisa A.A. [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Gomes, Ligia R. [CIAGEB, Faculdade de Ciencias de Saude Escola Superior de Saude da UFP, Universidade Fernando Pessoa, Rua Carlos da Maia, 296, P-4200-150 Porto (Portugal); REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Santos, Luis M.N.B.F., E-mail: lbsantos@fc.up.p [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)
2011-02-15
The thermodynamic study of the phase transition (fusion and sublimation) of 2,2':5',2''-terthiophene and 3,2':5',3''-terthiophene is presented. The obtained data is used to evaluate the (solid + liquid) and (solid + gas) phase equilibrium, and draw the phase diagrams of the pure compounds near the triple point coordinates. For each compound the vapour pressures at different temperatures were measured by a combined Knudsen effusion method with a vacuum quartz crystal microbalance. Based on the previous results, the standard molar enthalpies, entropies and Gibbs energies of sublimation were derived at T = 298.15 K. For the two terthiophenes and for 3,3'-bithiophene, the temperature, and the molar enthalpies of fusion were measured in a power compensated differential scanning calorimetry. The relationship between structure and energetics is discussed based on the experimental results, ab initio calculations and previous literature data for 2,2'-bithiophene and 3,3'-bithiophene. The 3,2':5',3''-terthiophene shows a higher solid phase stability than the 2,2':5',2''-terthiophene isomer arising from the higher cohesive energy due to positioning of the sulphur atom in the thiophene ring. The higher phase stability of 3,3'-bithiophene relative to 2,2'-bithiophene isomer is also related to its higher absolute entropy in the solid phase associated with the ring positional degeneracy observed in the crystal structure of this isomer. A significant differentiation in the crystal phase stability between isomers was found.
Topological phase transitions in superradiance lattices
Wang, Da-Wei; Yuan, Luqi; Liu, Ren-Bao; Zhu, Shi-Yao
2015-01-01
The discovery of the quantum Hall effect (QHE) reveals a new class of matter phases, topological insulators (TI's), which have been extensively studied in solid-state materials and recently in photonic structures, time-periodic systems and optical lattices of cold atoms. All these topological systems are lattices in real space. Our recent study shows that Scully's timed Dicke states (TDS) can form a superradiance lattice (SL) in momentum space. Here we report the discovery of topological phase transitions in a two-dimensional SL in electromagnetically induced transparency (EIT). By periodically modulating the three EIT coupling fields, we can create a Haldane model with in-situ tunable topological properties. The Chern numbers of the energy bands and hence the topological properties of the SL manifest themselves in the contrast between diffraction signals emitted by superradiant TDS. The topological superradiance lattices (TSL) provide a controllable platform for simulating exotic phenomena in condensed matte...