Related papers: QCD topology with electromagnetic fields and the a…
In this proceedings article we present a selected set of our lattice results regarding the effect that background electromagnetic fields have on the topology of QCD. In particular, we report on the lattice spacing-dependence of the…
We present the first determination of the topological susceptibility from lattice QCD in the presence of strong background magnetic fields. Our simulations employ 2+1 flavours of stout improved staggered quarks with physical masses and…
It is shown that gauge field configurations with higher topological charge modify the structure of the QCD vacuum, which is reflected in its dependence on the CP-violating topological phase $\theta$. To explore this, topological…
We present a formulation of Quantum Electrodynamics in terms of an antisymmetric tensor gauge field. In this formulation the topological current of this field appears as a source for the electromagnetic field and the topological charge…
Gauge theories with compact symmetry groups possess topologically non-trivial configurations of gauge field. This has dramatic implications for the vacuum structure of Quantum Chromo-Dynamics (QCD) and for the behavior of QCD plasma, as…
We study the electromagnetic properties of dense QCD in the so-called Magnetic Dual Chiral Density Wave phase. This inhomogeneous phase exhibits a nontrivial topology that comes from the fermion sector due to the asymmetry of the lowest…
We study the cosmological evolution of the QCD axion coupled to hidden photons. For a moderately strong coupling, the motion of the axion field leads to an explosive production of hidden photons by tachyonic instability. We use lattice…
The phase diagram and the equation of state of QCD is investigated in the presence of weak background electric fields by means of continuum extrapolated lattice simulations. The complex action problem at nonzero electric field is…
QCD axions are at the crossroads of QCD topology and Dark Matter searches. We present here the current status of topological studies on the lattice, and their implication on axion physics. We outline the specific challenges posed by lattice…
We present a mechanism wherein the QCD axion coupling to nucleons, photons, or electrons, can be enhanced selectively without increasing the axion mass. We focus in particular on the axion-nucleon couplings, that are generally considered to…
We study the $\theta$-vacuum of QCD using two-flavor chiral perturbation theory ($\chi$PT) in the presence of a uniform, background magnetic field calculating the magnetic field-dependent free energy density, the topological density, the…
The impact of dynamical fermions on the vacuum structure of QCD is explored. Of particular interest is the topological charge correlator, $<q(x) q(0) >$, where negative values at small $x$ reveal a sign-alternating layered structure to the…
Quantum Chromodynamics (QCD) is the theory of the strong interactions within the Standard Model of particle physics, which explains more than 99% of the mass of the visible Universe. However, there is evidence that a substantial portion of…
We present the results on topological susceptibility and chiral observables in $N_f=2+1+1$ QCD for temperature range $120<T<600$ MeV. The lattice simulations are performed with Wilson twisted mass fermions at physical pion, strange and…
In this proceedings we discuss the natural connection between the reduction of neutral pion mass in the vacuum, and the magnetic catalysis as well as the reduction of transition temperature in the external magnetic field. We also present…
The structure of topological charge fluctuations in the QCD vacuum is strongly restricted by the spectral negativity of the Euclidean 2-point correlator for $x\neq 0$ and the presence of a positive contact term. Some examples are considered…
The temperature dependence of the topological susceptibility in QCD, chi_t, essentially determines the abundance of the QCD axion in the Universe, and is commonly estimated, based on the instanton picture, to be a certain negative power of…
Off-central heavy-ion collisions are known to feature magnetic fields with magnitudes and characteristic gradients corresponding to the scale of the strong interactions. In this work, we employ equilibrium lattice simulations of the…
We investigate the topological properties of $N_f = 2+1$ QCD with physical quark masses, both at zero and finite temperature. We adopt stout improved staggered fermions and explore a range of lattice spacings $a \sim 0.05 - 0.12$ fm. At…
We study the topological susceptibility in 2+1 flavor QCD above the chiral crossover transition temperature using Highly Improved Staggered Quark action and several lattice spacings, corresponding to temporal extent of the lattice,…