Real time correlation functions and the functional renormalisation group

Abstract

We put forward a functional renormalisation group approach for the direct computation of real time correlation functions, also applicable at finite temperature and density. We construct a general class of regulators that preserve the space-time symmetries, and allows the computation of correlation functions at complex frequencies. This includes both imaginary time and real time, and allows in particular the use of the plethora of imaginary time results for the computation of real time correlation functions. We also discuss real time computation on the Keldysh contour with general spatial momentum regulators. Both set-ups give access to the general momentum and frequency dependence of correlation functions.

21 pages, 13 figures; v2: extended discussion of the analytical continuation, references added; v3: published version; v4: corrected typos

References in corpus (17)

• Exact evolution equation for the effective potential
• Chiral symmetry breaking in continuum QCD
• A perturbative nonequilibrium renormalization group method for dissipative quantum mechanics: Real-time RG in frequency space (RTRG-FS)
• Nonthermal fixed points and the functional renormalization group
• Fluctuations in the quark-meson model for QCD with isospin chemical potential
• Functional renormalisation group approach to far-from-equilibrium quantum field dynamics
• Towards quantitative precision in the chiral crossover: masses and fluctuation scales
• Flow equations for spectral functions at finite external momenta
• Far-from-equilibrium quantum many-body dynamics
• Renormalization group methods and the 2PI effective action
• On the analytic structure of scalar glueball operators at Born level
• Exact renormalization group and Phi-derivable approximations
• From quantum to classical dynamics: The relativistic $O(N)$ model in the framework of the real-time functional renormalization group
• Kondo model in nonequilibrium: Interplay between voltage, temperature, and crossover from weak to strong coupling
• Examining the Analytic Structure of Green's Functions: Massive Parallel Complex Integration using GPUs
• Two-particle irreducible functional renormalization group schemes---a comparative study
• Non-equilibrium time evolution of bosons from the functional renormalization group

Cited by in corpus (65)

• The nonperturbative functional renormalization group and its applications
• The QCD phase structure at finite temperature and density
• Extraction of Heavy-Flavor Transport Coefficients in QCD Matter
• Towards apparent convergence in asymptotically safe quantum gravity
• Renormalization group fixed points of foliated gravity-matter systems
• QCD at finite temperature and density within the fRG approach: An overview
• Fluctuation-induced modifications of the phase structure in (2+1)-flavor QCD
• In-Medium Spectral Functions of Vector- and Axial-Vector Mesons from the Functional Renormalization Group
• Brout-Englert-Higgs physics: From foundations to phenomenology
• On the relevance of matter and glue dynamics for baryon number fluctuations
• Graviton fluctuations erase the cosmological constant
• Finite temperature spectral functions in the O(N)-model
• Fierz-complete NJL model study: fixed points and phase structure at finite temperature and density
• Spectral functions in the ${\varphi }^4$-theory from the spectral DSE
• Spectrum of scalar and pseudoscalar glueballs from functional methods
• The Asymptotically Safe Standard Model: From quantum gravity to dynamical chiral symmetry breaking
• Bayesian analysis of quark spectral properties from the Dyson-Schwinger equation
• Modeling Finite-Volume Effects and Chiral Symmetry Breaking in Two-Flavor QCD Thermodynamics
• The spatial Functional Renormalization Group and Hadamard states on cosmological spacetimes
• Bound state properties from the Functional Renormalisation Group
• Spectral functions and critical dynamics of the $O(4)$ model from classical-statistical lattice simulations
• The flair of Higgsflare: Distinguishing electroweak EFTs with $W_L{W}_L\to n\times h$
• Spectral functions and dynamic critical behavior of relativistic $Z_2$ theories
• Vector and Axial-Vector Mesons in Nuclear Matter
• Towards QCD-assisted hydrodynamics for heavy-ion collision phenomenology
• Self-consistent Spectral Functions in the $O(N)$ Model from the FRG
• Spectral functions from the real-time functional renormalization group
• Renormalization Group Studies of Dense Relativistic Systems
• Meson Spectral Functions at Finite Temperature and Isospin Density with Functional Renormalization Group
• Fermionic spectral functions with the Functional Renormalization Group
• Tachyonic instability of the scalar mode prior to QCD critical point based on Functional renormalization-group method
• Mobile impurity in a Fermi sea from the functional renormalization group analytically continued to real time
• Real-time dynamics of the $O(4)$ scalar theory within the fRG approach
• An algebraic QFT approach to the Wetterich equation on Lorentzian manifolds
• On the quark spectral function in QCD
• Dependence of the propagators on the sampling of Gribov copies inside the first Gribov region of Landau gauge
• Pion and $\eta$-meson mass splitting at the two-flavour chiral crossover
• Nonperturbative functional renormalization-group approach to transport in the vicinity of a $(2+1)$-dimensional O($N$)-symmetric quantum critical point
• The QCD moat regime and its real-time properties
• Fluctuating vector mesons in analytically continued FRG flow equations
• Self-consistent $O(4)$ model spectral functions from analytically continued FRG flows
• Quantum renormalization group
• The Spectral Geometry of de Sitter Space in Asymptotic Safety
• Nonperturbative renormalization-group approach preserving the momentum dependence of correlation functions
• Spectral functions and in-medium properties of hadrons
• Fermionic excitations at finite temperature and density
• An asymptotically safe guide to quantum gravity and matter
• Regulator scheme dependence of the chiral phase transition at high densities
• Spectral representation of the shear viscosity for local scalar QFTs at finite temperature
• Thermalization and dynamical spectral properties in the quark-meson model
• Discrimination Between Quantum Common Causes and Quantum Causality
• Fermion spectral function in hot strongly interacting matter from the functional renormalization group
• Thermal dynamics on the lattice with exponentially improved accuracy
• Real-time correlators in 3+1D thermal lattice gauge theory
• Review of recent developments of the functional renormalization group for systems out of equilibrium
• Universality of pseudo-Goldstone damping near critical points
• Pseudo-scalar {\boldm $q\bar{q}$} bound states at finite temperatures within a Dyson-Schwinger--Bethe-Salpeter approach
• Quantum-classical transition in the Caldeira-Leggett model
• Phase Structure and Dynamics of QCD-- A Functional Perspective
• Coarse-graining in time with the Functional Renormalisation Group: Relaxation in Brownian Motion
• Functional Renormalisation Group for Brownian Motion I: The Effective Equations of Motion
• Physics-informed operator flows and observables
• Functional-renormalization-group approach to strongly coupled Bose-Fermi mixtures in two dimensions
• Functional Renormalization Analytically Continued
• Quantum fields without Wick rotation