17,798 research outputs found
Phase Diagram of the Extended Hubbard Model with Pair Hopping Interaction
A one-dimensional model of interacting electrons with on-site ,
nearest-neighbor , and pair-hopping interaction is studied at
half-filling using the continuum limit field theory approach. The ground state
phase diagram is obtained for a wide range of coupling constants. In addition
to the insulating spin- and charge-density wave phases for large and ,
respectively, we identify bond-located ordered phases corresponding to an
enhanced Peierls instability in the system for , , and to a
staggered magnetization located on bonds between sites for , .
The general ground state phase diagram including insulating, metallic, and
superconducting phases is discussed. A transition to the
-superconducting phase at is briefly
discussed.Comment: 6 pages in revtex format, 2 fig files in ep
Editorial : Autophagy : from big data to physiological significance
Autophagy is a fundamental catabolic process where cytoplasmic components are sequestered into double-membrane vesicles called autophagosomes, which then fuse with lysosomes and their content is degraded. Our knowledge about autophagy sharply increased during the last decade. This significant progress helped us to understand better the molecular mechanisms of autophagy and to elucidate its role in health and disease. This special issue contains a collection of three original research papers and 12 review articles covering a broad range of topics highlighting how big data and screening approaches can help toward uncovering the molecular mechanisms of autophagy
Truly Minimal Left-Right Model of Quark and Lepton Masses
We propose a left-right model of quarks and leptons based on the gauge group
, where the scalar
sector consists of only two doublets: (1,2,1,1) and (1,1,2,1). As a result, any
fermion mass, whether it be Majorana or Dirac, must come from dimension-five
operators. This allows us to have a common view of quark and lepton masses,
including the smallness of Majorana neutrino masses as the consequence of a
double seesaw mechanism.Comment: Version to appear in PRL, title changed by journal to "Left-right
model of quark and lepton masses without a scalar bidoublet
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Adolescents' and parents' views of Child and Adolescent Mental Health Services (CAMHS) in Ireland
Aim: To explore adolescents’ and parents’ experiences of CAMHS in relation to accessibility, approachability, and appropriateness. Methods: Using a descriptive qualitative design, a combination of focus group and single interviews were conducted with adolescents (n=15) and parents (n=32) from three mental health clinics. Data were transcribed verbatim and analysed using thematic analysis. Results: Accessing mental health services was a challenging experience due to knowledge deficit, lack of information and limited availability of specialist services. Participants desired more information, involvement in decision-making, single and shared consultations, flexible scheduling of appointments, continuity with clinicians, school support and parent support groups. Participants seem to be generally satisfied, however adolescents felt less involved in decision making than they would have liked. Frequent staff changes was problematic as it disrupted continuity of care and hindered the formation of a trusting relationship. Implications for practice: Parents and adolescents expressed similar views of the positive and negative aspects of mental health services. Their need for more information-sharing and involvement in decision-making underline the importance of collaborative practice. Clinician continuity contributed to trusting therapeutic relationships and was valued. These are key principles that with attention, could lead to quality service provision for adolescents and families
Character of Locally Inequivalent Classes of States and Entropy of Entanglement
In this letter we have established the physical character of pure bipartite
states with the same amount of entanglement in the same Schmidt rank that
either they are local unitarily connected or they are incomparable. There exist
infinite number of deterministically locally inequivalent classes of pure
bipartite states in the same Schmidt rank (starting from three) having same
amount of entanglement. Further, if there exists incomparable states with same
entanglement in higher Schmidt ranks (greater than three), then they should
differ in at least three Schmidt coefficients.Comment: 4 pages, revtex4, no figure, accepted in Physical Review A (rapid
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Investigation into the limits of perturbation theory at low Q^2 using HERA deep inelastic scattering data
A phenomenological study of the final combined HERA data on inclusive deep
inelastic scattering (DIS) has been performed. The data are presented and
investigated for a kinematic range extending from values of the four-momentum
transfer, , above 10 GeV down to the lowest values observable at
HERA of = 0.045 GeV and Bjorken , = 6
10. The data are well described by fits based on perturbative quantum
chromodynamics (QCD) using collinear factorisation and evolution of the parton
densities encompassed in the DGLAP formalism from the highest down to
of a few GeV. The Regge formalism can describe the data up to 0.65 GeV. The complete data set can be described by a new fit
using the ALLM parameterisation. The region between the Regge and the
perturbative QCD regimes is of particular interest.Comment: 38 pages, 13 figure
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