Dr. Efrain Ferrer
Professor
ESCNE 3.618
Phone pending-
Edinburg
efrain.ferrer@utrgv.edu
Research
Research is described here:Nuclear/High-Energy Theoretical Physics
Publications
My publications are described here:Publications
Nuclear/High-Energy Theoretical Physics.
The UTRGV theoretical group in Nuclear and High-Energy Physics had covered a wide spectrum of research topics, including applications to cosmology and astrophysics. At present, problems aimed to investigate the properties of the different phases of quark matter at finite temperature and density and under the influence of strong magnetic fields have becomes its main research focus. The outcomes of these investigations can be of relevance for the physics of the quark-gluon plasma created in the aftermath of heavy-ion collisions, as well as for the astrophysics of highly magnetized compact stars, as the so-called magnetars. The group research has been continually funded by NSF and DOE research grants. Over the years, the group members have developed international collaborations with scientists from institutions as the Bogoliubov Theoretical Physics Institute (Kiev, Ukraine), the Institute for Space Studies of Catalonia, Spain, the Institute of Astronomy, Geophysics and Atmospheric Sciences of the Univ. of Sao Paulo, Brazil, the Institute of Theoretical Physics, Shanxi University, Taiyuan, China, and the Interdisciplinary Center for Theoretical Study of the University of Science and Technology of China, Hefei, China. Graduate and undergraduate students had participated in the group research. In the last years the group faculty members had trained five post-docs (two of them supported by grants of their countries (China and Brazil)), nine graduate and six undergraduate students and two high-school students.
Figure from: Phase diagram of simplified QCD
QCD Phase Diagram
Baryonic matter has a rich phase structure (see the QCD Phase Diagram above). In its usual temperatureversus baryon-number density phase map, color superconductivity is the well-established ground state in theasymptotically large density and low temperature region. This phase is characterized by the formation of quark-quark pairs analogous to the BCS pairs of conventional electronic superconductivity. This phase is expected to be realized in the very dense core of compact stars. While on the other extreme of low-density/low-temperature region, the quarks are confined into hadrons having large masses produced by thebreaking of chiral symmetry due to the chiral homogeneous condensate formed by quark-antiquark pairs. The region of extreme high temperature and low density is described by the quark-gluon plasma phase (QGP). The exploration of this region has been made possible thanks to the heavy-ion collisions experiments carried out by the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab (BNL) and by the Large Hadron Collider (LHC) at CERN. The top center-of-mass energies per nucleon pair reached have been √s = 200 GeV for the Au-Au collisions at RHIC, and √s = 2.76 TeV for the Pb-Pb collisions at LHC. These energies are large enough to deconfine the quarks from inside the hadrons and produce the QGP. The results of these experiments and those planned at LHC, that will reach √s = 5.5 TeV, will help to increase the precision of the physical findings for quark-gluon matter in the region of high temperature and low density. On the other hand, the Nuclotron-based Ion Collider Facility (NICA) at JINR will open the possibility to improve the picture of the QCD phase map by extending it to the region of intermediate-to-large densities at lower temperatures. In theintermediate density region, however, the energetically favored ground state al low temperature remains murky since neither perturbative QCD nor lattice calculations are applicable in that region.
Notably, in most situations where quark-matter phases can be generated, magnetic fields are usually present. Thus, of particular interest for the understanding of the different phases that can be produced in the above-mentioned experiments are the effects related to the presence of strong magnetic fields. Off-central heavy-ion collision can generate large magnetic fields. According to several numerical simulations, off-central Au-Au collisions at RHIC can lead to field strengths of 1018 − 1019 G, while the field can be as large as 1020 G for the off-central Pb-Pb collisions at LHC. These strong magnetic fields, produced during the first instants after a collision, can create the conditions for observable QCD effects. Likewise, neutron stars typically have strong magnetic fields. Estimates based on the scalar virial theorem give inner fields for magnetars of order 1018 G for nuclear matter and 1020 G for quark matter. Even inner fields, one to three orders of magnitude smaller, would be significant and should not be ignored in NS studies
Many of the most recent research works produced in our group are devoted to elucidate the properties of dense quark matter in the presence of strong magnetic fields.