Abstract
Lattice simulations have demonstrated that a background (electro)magnetic field reduces the chiral/deconfinement transition temperature of quantum chromodynamics for eB < 1 GeV2. On the level of observables, this reduction manifests itself in an enhancement of the Polyakov loop and in a suppression of the light quark condensates (inverse magnetic catalysis) in the transition region. In this paper, we report on lattice simulations of 1 + 1 + 1-flavor QCD at an unprecedentedly high value of the magnetic field eB = 3.25 GeV2. Based on the behavior of various observables, it is shown that even at this extremely strong field, inverse magnetic catalysis prevails and the transition, albeit becoming sharper, remains an analytic crossover. In addition, we develop an algorithm to directly simulate the asymptotically strong magnetic field limit of QCD. We find strong evidence for a first-order deconfinement phase transition in this limiting theory, implying the presence of a critical point in the QCD phase diagram. Based on the available lattice data, we estimate the location of the critical point.
Highlights
The magnetic catalysis of the condensate at low temperatures is a very robust concept
We find strong evidence that this limiting theory has a first-order deconfinement phase transition and, the QCD phase diagram exhibits a critical point at strong magnetic fields, where the analytic crossover terminates
In addition to the data at nonzero temperatures, we indicate an estimate for the zero-temperature condensate
Summary
The magnetic catalysis of the condensate at low temperatures is a very robust concept. Several attempts have been made recently to understand this behavior in effective approaches to QCD [16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33], among others, by introducing new, B-dependent model parameters or by taking into account the running of the QCD coupling with the magnetic field. It was even shown that no matter how the existing parameters of the model are tuned as functions of B, the transition temperature always tends to rise above a given threshold magnetic field [34] It is just the apparent universality of magnetic catalysis that has made the lattice results about inverse catalysis and the decreasing Tc(B) dependence for 0 ≤ eB < 1 GeV2 so unexpected.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
