Spectral functions from the functional renormalization group

Wambach, J.; Tripolt, Ralf-Arno; Strodthoff, Nils; Smekal, Lorenz von

doi:10.1016/j.nuclphysa.2014.04.027

Cited by 11 publications

(10 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has recently been pointed out that the NPRG enables, within some approximation schemes, to perform exactly both Matsubara-frequency sums and analytical continuation to real frequencies. [59][60][61][62] Other methods to circumvent the difficulties in performing analytical continuation at finite temperature from numerical data have been proposed. 63 Whether or not these proposals can be successfully implemented for the quantum O(N ) model is likely to determine whether the NPRG is a reliable method to compute finite-temperature transport properties.…”

Section: Discussionmentioning

confidence: 99%

Nonperturbative functional renormalization-group approach to transport in the vicinity of a(2+1)-dimensional O(N)-symmetric quantum critical point

Rose

Dupuis

2017

Phys. Rev. B

View full text Add to dashboard Cite

Using a nonperturbative functional renormalization-group approach to the two-dimensional quantum O(N ) model, we compute the low-frequency limit ω → 0 of the zero-temperature conductivity in the vicinity of the quantum critical point. Our results are obtained from a derivative expansion to second order of a scale-dependent effective action in the presence of an external (i.e., non-dynamical) non-Abelian gauge field. While in the disordered phase the conductivity tensor σ(ω) is diagonal, in the ordered phase it is defined, when N ≥ 3, by two independent elements, σ A (ω) and σ B (ω), respectively associated to SO(N ) rotations which do and do not change the direction of the order parameter. For N = 2, the conductivity in the ordered phase reduces to a single component σ A (ω). We show that limω→0 σ(ω, δ)σ A (ω, −δ)/σ 2 q is a universal number which we compute as a function of N (δ measures the distance to the quantum critical point, q is the charge and σq = q 2 /h the quantum of conductance). On the other hand we argue that the ratio σ B (ω → 0)/σq is universal in the whole ordered phase, independent of N and, when N → ∞, equal to the universal conductivity σ * /σq at the quantum critical point.

show abstract

Section: Discussionmentioning

confidence: 99%

Nonperturbative functional renormalization-group approach to transport in the vicinity of a(2+1)-dimensional O(N)-symmetric quantum critical point

Rose

Dupuis

2017

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…It should be mentioned that, recently, an alternative formulation of the NPRG capable of dealing with the analytic continuation of spectral functions has been proposed in a slightly different context [51][52][53]. In this approach, the analytic continuation is performed at the level of the flow equations of the NPRG, so that one ends up with a flow of complex quantities.…”

Section: And One For the Derivative Of The Dimensionless Effective Po...mentioning

confidence: 99%

Bound states of the $ϕ^4$ model via the nonperturbative renormalization group

Rose,

Benitez,

Leonard

et al. 2016

Preprint

View full text Add to dashboard Cite

Using the nonperturbative renormalization group, we study the existence of bound states in the symmetry-broken phase of the scalar φ 4 theory in all dimensions between two and four and as a function of the temperature. The accurate description of the momentum dependence of the two-point function, required to get the spectrum of the theory, is provided by means of the Blaizot-Méndez-Galain-Wschebor approximation scheme. We confirm the existence of a bound state in dimension three, with a mass within 1% of previous Monte-Carlo and numerical diagonalization values.

show abstract

“…This is, however, a challenging problem. One possible approach, for which realtime behavior becomes more and more accessible, are functional methods [5][6][7][8]. Still, these methods require approximations.…”

Section: Introductionmentioning

confidence: 99%

Exploratory study of the temperature dependence of magnetic vertices in SU(2) Landau gauge Yang-Mills theory

Fister

Maas²

2014

Phys. Rev. D

View full text Add to dashboard Cite

(present address) Vertices describe the interactions between the fundamental degrees of freedom, and are therefore of vital importance in many ab initio descriptions of field theory, especially using functional methods. To this end, we present the first lattice study of the thermal behavior of (minimal) Landau-gauge SU (2) Yang-Mills three-point functions, i.e. three-gluon and ghost-gluon vertices. Focusing on the chromomagnetic sector, we find that the phase transition mainly affects the three-gluon vertex, while the ghost-gluon vertex is relatively inert.

show abstract

Spectral functions from the functional renormalization group

Cited by 11 publications

References 25 publications

Nonperturbative functional renormalization-group approach to transport in the vicinity of a(2+1)-dimensional O(N)-symmetric quantum critical point

Nonperturbative functional renormalization-group approach to transport in the vicinity of a(2+1)-dimensional O(N)-symmetric quantum critical point

Bound states of the $ϕ^4$ model via the nonperturbative renormalization group

Exploratory study of the temperature dependence of magnetic vertices in SU(2) Landau gauge Yang-Mills theory

Contact Info

Product

Resources

About