3,832 research outputs found
Universal quantum criticality at the Mott-Anderson transition
We present a large N solution of a microscopic model describing the
Mott-Anderson transition on a finite-coordination Bethe lattice. Our results
demonstrate that strong spatial fluctuations, due to Anderson localization
effects, dramatically modify the quantum critical behavior near disordered Mott
transitions. The leading critical behavior of quasiparticle wavefunctions is
shown to assume a universal form in the full range from weak to strong
disorder, in contrast to disorder-driven non-Fermi liquid ("electronic
Griffiths phase") behavior, which is found only in the strongly correlated
regime.Comment: 4 pages + references, 4 figures; v2: minor changes, accepted for
publication in Phys. Rev. Let
Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective
We present a detailed analysis of the critical behavior close to the
Mott-Anderson transition. Our findings are based on a combination of numerical
and analytical results obtained within the framework of Typical-Medium Theory
(TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT)
capable of incorporating Anderson localization effects. By making use of
previous scaling studies of Anderson impurity models close to the
metal-insulator transition, we solve this problem analytically and reveal the
dependence of the critical behavior on the particle-hole symmetry. Our main
result is that, for sufficiently strong disorder, the Mott-Anderson transition
is characterized by a precisely defined two-fluid behavior, in which only a
fraction of the electrons undergo a "site selective" Mott localization; the
rest become Anderson-localized quasiparticles.Comment: 4+ pages, 4 figures, v2: minor changes, accepted for publication in
Phys. Rev. Let
Non universality of entanglement convertibility
Recently, it has been suggested that operational properties connected to
quantum computation can be alternative indicators of quantum phase transitions.
In this work we systematically study these operational properties in 1D systems
that present phase transitions of different orders. For this purpose, we
evaluate the local convertibility between bipartite ground states. Our results
suggest that the operational properties, related to non-analyticities of the
entanglement spectrum, are good detectors of explicit symmetries of the model,
but not necessarily of phase transitions. We also show that thermodynamically
equivalent phases, such as Luttinger liquids, may display different
convertibility properties depending on the underlying microscopic model.Comment: 5 pages + references, 4 figures - improved versio
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