Paul Romatschke's homepage

INT
University of Washington
Physics/Astronomy Building
Box 351550
Seattle, WA 98195-1550
USA

Phone: +1-206-685-3970
Fax: +1-206-685-9829
E-Mail: paulrom AT phys DOT washington DOT edu
CV


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Hydrodynamic Simulation of a Au+Au Collision: Temperature Profile

General


I am in my fourth year of my 5-year fellow position at the INT, University of Washington, USA. See below for a short summary of my recent research interests or view a list of my articles at SPIRES. If you came here looking for the the homepage of my wife Ulrike Romatschke, follow this link.

Recent Events

08/2009: 2+1d viscous hydro code version 0.2 released (Download)
12/2009: Preprint "Cold Quark Matter": see below under "Various Projects" or read a news article about it at physicsworld.com

Relativistic Viscous Hydrodynamics


The recent paradigm of the ideal fluid created at the relativistic heavy-ion collider (RHIC) has been embraced by many experimentalists and theorists alike. Strangely enough, much "evidence" to this notion has been based on the success of describing experimental data by non-viscous hydrodynamics. Work on the subject of viscous hydrodynamics evolved from studies in 0+1 dimensions ("Bjorken flow") over 1+1 dimensions ("Transverse flow") to 2+1 dimensions ("Elliptic flow"). More formal issues concern the allowed form of the relativistic viscous hydrodynamics equations and what effect fluid turbulence (if it develops) might have.
  1. P. Romatschke, Relativistic Viscous Fluid Dynamics and Non-Equilibrium Entropy, PDF, Abstract, (2009).
    Comments: Most general form of 2nd order non-conformal fluid dynamic equations (at zero charge density). Also derived is the form of the non-equilibrium entropy current in the fluid dynamics regime.
  2. P. Romatschke, New Developments in Relativistic Viscous Hydrodynamics, PDF, Abstract, (2009).
    Comments: Review of recent progress in relativistic viscous hydrodynamics.
  3. M. Luzum and P. Romatschke, Viscous Hydrodynamic Predictions for Nuclear Collisions at the LHC PDF, Abstract, (2009).
    Comments: Predictions for lead-lead and proton-proton collisions at the LHC. Download code and results here!
  4. M. Luzum and P. Romatschke, Conformal Relativistic Viscous Hydrodynamics: Applications to RHIC PDF, Abstract, Phys.Rev.C78:034915 (2008)
    Comments: Results from conformal viscous hydro on Au+Au collisions at RHIC, for Glauber and CGC initial conditions. Details of Setup. Dependence on 2nd order coefficients and Cooper-Frye ansatz discussed. Discussion of early thermalization and viscosity over entropy ratio. Download Results here!
    Update: we fixed a bug in the calculation for the resonances (see published erratum: Phys.Rev.C79:039903(E), 2008); revised plots/data will be made available soon.
  5. R. Baier, P. Romatschke, D.T. Son, A.O. Starinets, M.A. Stephanov, Relativistic viscous hydrodynamics, conformal invariance, and holography, PDF, Abstract, JHEP 0804:100, (2008).
    Comments: Fixing the form of second-order relativistic viscous hydrodynamic equations; supersedes Israel-Stewart theory
  6. Paul Romatschke, Fluid turbulence and eddy viscosity in relativistic heavy-ion collisions, PDF, Abstract, (2007).
    Comments: Thoughts about Fluid Turbulence
  7. Paul Romatschke, Ulrike Romatschke, How perfect is the RHIC fluid? PDF, Abstract, Phys. Rev. Lett.99, 172301 (2007).
    Comments: Viscous Hydrodynamics for Non-central Collisions, Elliptic flow, Comparison to Data
    Download Code here!
  8. Paul Romatschke, Causal Viscous Hydrodynamics for Central Heavy-Ion Collisions II: Meson Spectra and HBT Radii PDF, Abstract, Eur.Phys.J.C52:203-209 (2007).
    Comments: Viscous Hydrodynamics for Central Collisions, Freeze-Out and Comparison to Data
    Download Code+Results here!
  9. Rudolf Baier, Paul Romatschke, Causal Viscous Hydrodynamics for Central Heavy-Ion Collisions, PDF, Abstract, Eur.Phys.J.C51:677-687 (2007).
    Comments: Viscous Hydrodynamics for Central Collisions, Transverse flow, Code tests
  10. Rudolf Baier, Paul Romatschke, Urs Achim Wiedemann, Transverse flow in relativistic viscous hydrodynamics, PDF, Abstract, Nucl.Phys.A782:313-318 (2007).
    Comments: How not to Approximate Viscous Hydrodynamic Equations
  11. Rudolf Baier, Paul Romatschke, Urs Achim Wiedemann, Dissipative hydrodynamics and heavy ion collisions, PDF, Abstract, Phys.Rev.C73, 064903 (2006).
    Comments: Viscous Hydrodynamic Equations I, Bjorken flow.

Non-Abelian Plasma Instabilities


Plasma instabilities in QCD are a very interesting and rich phenomenon that may perhaps lead to fast equilibration in the context of heavy-ion collisions. Much progress has been made in recent years, but a thorough understanding of non-Abelian plasma instabilities in heavy-ion collisions is still missing.
Below is a list of my contributions to this topic,
  1. P. Romatschke, Momentum broadening in an anisotropic plasma, PDF, Abstract, Phys. Rev. C75, 014901 (2007).
    Comments: Jet broadening in an anisotropic QCD plasma: "the ridge"
    See arxiv source for numerics
  2. P. Romatschke and A. Rebhan, Plasma Instabilities in an Anisotropically Expanding Geometry, PDF, Abstract, Phys. Rev. Lett.97, 252301 (2006).
  3. P. Romatschke and R. Venugopalan, The Unstable Glasma, PDF, Abstract, Phys. Rev. D74, 045011 (2006)
  4. P. Romatschke and R. Venugopalan, A Weibel instability in the melting color glass condensate PDF, Abstract, Eur. Phys. J. A29:71-75 (2006).
  5. P. Romatschke and R. Venugopalan, Collective Non-Abelian Instabilities in a Melting Color Glass Condensate, PDF, Abstract, Phys. Rev. Lett.96, 062302 (2006).
    Comments: Full 3D simulation of classical chromodynamics in expanding space
    Download Code here!
  6. A. Rebhan, P. Romatschke and M. Strickland, Quark-Gluon-Plasma Instabilities in Discretized Hard-Loop Approximation, PDF, Abstract, JHEP 0509:041 (2005).
  7. A. Rebhan, P. Romatschke and M. Strickland, Hard-Loop dynamics of Non-Abelian Plasma Instabilities, PDF, Abstract, Phys. Rev. Lett.94, 102303 (2005).
  8. P. Romatschke and M. Strickland, Progress in Anisotropic Plasma Physics, PDF, Abstract (2004).
  9. P. Romatschke and M. Strickland, Collisional Energy Loss of a Heavy Quark in an Anisotropic Quark-Gluon Plasma, PDF, Abstract, Phys.Rev.D71, 125008 (2005).
  10. P. Romatschke and M. Strickland, Collective Modes of an Anisotropic Quark-Gluon Plasma II, PDF, Abstract (2004), Phys. Rev. D70, 116006 (2004).
  11. P. Romatschke and M. Strickland, Energy Loss of a Heavy Fermion in an Anisotropic QED Plasma, PDF, Abstract, Phys. Rev. D 69, 065005 (2004).
  12. P. Romatschke and M. Strickland, Collective Modes of an Anisotropic Quark-Gluon Plasma, PDF, Abstract, Phys. Rev. D 68, 036004 (2003).

Nonlinear Gravity

  1. Daniel Grumiller, Paul Romatschke, On the collision of two shock waves in AdS5 PDF, Abstract, JHEP 0808:027 (2008).
    Comments: A (partial) solution to a toy model of a high energy particle collision in a strongly coupled gauge theory.

Various other projects

  1. A. Kurkela, P. Romatschke and A. Vuorinen, Cold Quark Matter, PDF, Abstract, (2009).
    Comments: Perturbation theory to O(alpha_s^2) for cold and dense QCD matter with full strange quark mass effects included (supersedes Freedman/McLerran/Baluni's result). Constraints on strange quark matter, strangelets, and hybrid quark stars.
    Results available here.
  2. P. Romatschke and D.T. Son, Spectral sum rules for the quark-gluon plasma, PDF, Abstract, Phys.Rev.D80:065021 (2009).
    Comments: Sum rules for Energy-Momentum Tensor Correlators in SU(N) and N=4 SYM.
    C++ code used to check sum rules for N=4 SYM is available here.
  3. M. Laine, O. Philipsen, P. Romatschke, M. Tassler, Real-time static potential in hot QCD, PDF, Abstract, JHEP 0703:054 (2007).
    Comments: Quarkonia
  4. Eduardo S. Fraga, Paul Romatschke, The Role of quark mass in cold and dense perturbative QCD, PDF, Abstract, Phys.Rev.D71:105014 (2005).
    Comments: Strange stars, Quark stars, neutron stars?
  5. Paul Romatschke, Quasiparticle description of the hot and dense quark gluon plasma. PDF, Abstract, (2003).
    Comments: PhD thesis
  6. Anton Rebhan, Paul Romatschke, HTL quasiparticle models of deconfined QCD at finite chemical potential, PDF, Abstract, Phys.Rev.D68:025022 (2003).
    Comments: The HTL Quasiparticle model
    Download results here !
  7. Paul Romatschke, Cold deconfined matter EOS through an HTL quasiparticle model, PDF, Abstract, (2002).
    Comments: My first preprint :-)
  8. Paul Romatschke, Thermal corrections to the sunset diagram, unpublished, ps (2001).
    Comments: Diploma thesis

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