1,721,081 research outputs found
Interplay of Superconductivity and Magnetism in a t-t′-J Approach to High T c Cuprates
No full textWe review a recently proposed mechanism for
superconductivity in hole-doped cuprates exhibiting a
strong interplay between pairing and antiferromagnetism.
Starting from the t-t
-J model for the CuO planes, we show
that this interplay can explain in a unified framework the
pseudogap phenomenology of the spectral weight of the
hole, the hourglass-like structure of the magnetic excitation,
the critical exponent of the superfluid density, the relation
between the scale of the magnetic resonance and Tc
Spin-statistics transmutation in quantum field theory
No full textSpin-statistics transmutation is the phenomenon occurring when a “dressing”
transformation introduced for physical reasons (e.g. gauge invariance) modifies
the “bare” spin and statistics of particles or fields. Historically, it first appeared in
Quantum Mechanics and in semiclassical approximation to Quantum Field Theory.
After a brief historical introduction, we sketch how to describe such phenomenon in
Quantum Field Theory beyond the semiclassical approximation, using a path-integral
formulation of euclidean correlation functions, exemplifying with anyons, dyons and
skyrmions
CONFINEMENT - DECONFINEMENT ORDER PARAMETER AND DIRAC'S QUANTIZATION CONDITION
No full textWe describe a monopole-like order parameter for the confinement-deconfinement transition in gauge theories where dynamical charges and monopoles coexist. It has been recently proposed in a collaboration with J. Froehlich. It avoids an inconsistency in the treatment of small scales present in earlier definitions of monopole fields by respecting Dirac's quantization condition for electromagnetic fluxes. An application to SU(2) lattice Yang-Mills theory is outlined, naturally fitting in the 't Hooft scenario for confinement
Particle structure analysis of soliton sectors in massive lattice field theories.
No full textWe discuss the particle structure in the soliton sectors of massive lattice field theories by means of convergent cluster expansions. In several models we prove that the soliton field operator with lowest charge couples the vacuum to a stable one-particle state, in a suitable region of the coupling parameter space. Both local and stringlike solitons are analyzed. We also show that the mass of the local soliton equals the surface tension
Constructing quantum kinks by differential geometry and statistical mechanics.
No full textWe construct the kink sector of the phi24 quantum field theory, in the broken-symmetry phase, using Euclidean methods. The construction exhibits relations with differential geometry and statistical mechanics. In particular we prove that the Euclidean Green's functions of kinks are obtained by integration over section distributions of nontrivial bundles and are well defined as Jaffe ultradistributions
U(1) X SU(2) GAUGE THEORY OF UNDERDOPED HIGH T(C) CUPRATES VIA CHERN-SIMONS BOSONIZATION
No full textWe outline the basic ideas involved in a recently proposed derivation of a gauge theory for underdoped cuprates in the "spin-gap phase", performed essentially step by step starting from the t-J model, considered as a model Hamiltonian for the CuO_2 layers. The basic tool is the U(1)XSU(2) Chern-Simons bosonization, to which it is dedicated a somewhat detailed discussion. The basic output is a "spin-gap" not vanishing in any direction and an antiferromagnetic correlation length proportional to the inverse square root of doping concentration, in agreement with data deduced from the neutron experiments. The model also exhibits a small half-pocket Fermi surface around (\pi/2, \pi/2) and a linear in temperature dependence of in-plane resistivity in certain temperature range
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