83 research outputs found
Towards Quantum Simulating QCD
Quantum link models provide an alternative non-perturbative formulation of
Abelian and non-Abelian lattice gauge theories. They are ideally suited for
quantum simulation, for example, using ultracold atoms in an optical lattice.
This holds the promise to address currently unsolvable problems, such as the
real-time and high-density dynamics of strongly interacting matter, first in
toy-model gauge theories, and ultimately in QCD.Comment: 8 pages, 4 figures, plenary talk at Quark Matter 2014, submitted as a
proceedings contribution to Nuclear Physics
Non-trivial \theta-Vacuum Effects in the 2-d O(3) Model
We study \theta-vacua in the 2-d lattice O(3) model using the standard action
and an optimized constraint action with very small cut-off effects, combined
with the geometric topological charge. Remarkably, dislocation lattice
artifacts do not spoil the non-trivial continuum limit at \theta\ non-zero, and
there are different continuum theories for each value of \theta. A very precise
Monte Carlo study of the step scaling function indirectly confirms the exact
S-matrix of the 2-d O(3) model at \theta = \pi.Comment: 4 pages, 3 figure
Rotor Spectra and Berry Phases in the Chiral Limit of QCD on a Torus
We consider the finite-volume spectra of QCD in the chiral limit of massless
up and down quarks and massive strange quarks in the baryon number sectors and for different values of the isospin. Spontaneous symmetry
breaking gives rise to rotor spectra, as the chiral order parameter precesses
through the vacuum manifold. Baryons of different isospin influence the motion
of the order parameter through non-trivial Berry phases and associated abstract
monopole fields. Our investigation provides detailed insights into the dynamics
of spontaneous chiral symmetry breaking in QCD on a torus. It also sheds new
light on Berry phases in the context of quantum field theory. Interestingly,
the Berry gauge field resulting from QCD solves a Yang-Mills-Chern-Simons
equation of motion on the vacuum manifold .Comment: 21 pages, 3 figures. Revised version: Slightly expanded introduction
and conclusion, a few references adde
Real-Time Evolution of Strongly Coupled Fermions driven by Dissipation
We consider the real-time evolution of a strongly coupled system of lattice
fermions whose dynamics is driven entirely by dissipative Lindblad processes,
with linear or quadratic quantum jump operators. The fermion 2-point functions
obey a closed set of differential equations, which can be solved with linear
algebra methods. The staggered occupation order parameter of the t-V model
decreases exponentially during the dissipative time evolution. The structure
factor associated with the various Fourier modes shows the slowing down of
low-momentum modes, which is due to particle number conservation. The processes
with nearest-neighbor-dependent Lindblad operators have a decay rate that is
proportional to the coordination number of the spatial lattice.Comment: 15 pages, 4 figure
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