59,332 research outputs found
Exclusive photoproduction of quarkonium in proton-nucleus collisions at energies available at the CERN Large Hadron Collider
In this work we investigate the coherent photoproduction of psi(1S), psi(2S)
and Upsilon (1S) states in the proton-nucleus collisions in the LHC energies.
Predictions for the rapidity distributions are presented using the color dipole
formalism and including saturation effects that are expected to be relevant at
high energies. Calculations are done at the energy 5.02 TeV and also for the
next LHC run at 8.8 TeV in proton-lead mode. Discussion is performed on the
main theoretical uncertainties associated to the calculations.Comment: 05 pages, 5 figures. Version to be published in Phys. Rev.
Light vector meson photoproduction in hadron-hadron and nucleus-nucleus collisions at the energies available at the CERN Large Hadron Collider
In this work we analyse the theoretical uncertainties on the predictions for
the photoproduction of light vector mesons in coherent pp, pA and AA collisions
at the LHC energies using the color dipole approach. In particular, we present
our predictions for the rapidity distribution for rh0 and phi photoproduction
and perform an analysis on the uncertainties associated to the choice of vector
meson wavefunctionand the phenomenological models for the dipole cross section.
Comparison is done with the recent ALICE analysis on coherent production of rho
at 2.76 TeV in PbPb collisions.Comment: 07 pages, 6 figures. Version to be published in Phys. Rev.
Divide and conquer: resonance induced by competitive interactions
We study an Ising model in a network with disorder induced by the presence of
both attractive and repulsive links. This system is subjected to a subthreshold
signal, and the goal is to see how the response is enhanced for a given
fraction of repulsive links. This can model a network of spin-like neurons with
excitatory and inhibitory couplings. By means of numerical simulations and
analytical calculations we find that there is an optimal probability, such that
the coherent response is maximal
Diffractive dissociation in proton-nucleus collisions at collider energies
The cross section for the nuclear diffractive dissociation in proton-lead
collisions at the LHC is estimated. Based on the current theoretical
uncertainties for the single (target) diffactive cross section in hadron-hadron
reactions one obtains sigma_SD(5.02 TeV) = 19.67 \pm 5.41 mb and sigma_SD(8.8
TeV) = 18.76 \pm 5.77 mb, respectively. The invariant mass M_X for the reaction
pPb -> pX is also analyzed. Discussion is performed on the main theoretical
uncertainties associated to the calculations.Comment: 04 pages, 2 figures. Final version to be published in European
Physical Journal A - "Hadrons and Nuclei
Entanglement guided search for parent Hamiltonians
We introduce a method for the search of parent Hamiltonians of input
wave-functions based on the structure of their reduced density matrix. The two
key elements of our recipe are an ansatz on the relation between reduced
density matrix and parent Hamiltonian that is exact at the field theory level,
and a minimization procedure on the space of relative entropies, which is
particularly convenient due to its convexity. As examples, we show how our
method correctly reconstructs the parent Hamiltonian correspondent to several
non-trivial ground state wave functions, including conformal and
symmetry-protected-topological phases, and quantum critical points of
two-dimensional antiferromagnets described by strongly coupled field theories.
Our results show the entanglement structure of ground state wave-functions
considerably simplifies the search for parent Hamiltonians.Comment: 5 pages, 5 figures, supplementary materia
Measuring von Neumann entanglement entropies without wave functions
We present a method to measure the von Neumann entanglement entropy of ground
states of quantum many-body systems which does not require access to the system
wave function. The technique is based on a direct thermodynamic study of
entanglement Hamiltonians, whose functional form is available from field
theoretical insights. The method is applicable to classical simulations such as
quantum Monte Carlo methods, and to experiments that allow for thermodynamic
measurements such as the density of states, accessible via quantum quenches. We
benchmark our technique on critical quantum spin chains, and apply it to
several two-dimensional quantum magnets, where we are able to unambiguously
determine the onset of area law in the entanglement entropy, the number of
Goldstone bosons, and to check a recent conjecture on geometric entanglement
contribution at critical points described by strongly coupled field theories
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