scholarly journals Low-energy theory of thet−t′−t″−UHubbard model at half-filling: Interaction strengths in cuprate superconductors and an effective spin-only description ofLa2CuO4

2009 ◽  
Vol 79 (23) ◽  
Author(s):  
J.-Y. P. Delannoy ◽  
M. J. P. Gingras ◽  
P. C. W. Holdsworth ◽  
A.-M. S. Tremblay
Keyword(s):  
Cuprate Superconductors ◽  
Low Energy ◽  
Effective Spin ◽  
Half Filling ◽  
Energy Theory

scholarly journals Mottness collapse and T -linear resistivity in cuprate superconductors

2011 ◽  
Vol 369 (1941) ◽  
pp. 1574-1598 ◽  
Author(s):  
Philip Phillips
Keyword(s):  
Short Range ◽  
Degrees Of Freedom ◽  
Cuprate Superconductors ◽  
High Temperature Superconductors ◽  
Spectral Weight ◽  
Quantum Criticality ◽  
Low Energy ◽  
Energy Theory ◽  
Weight Transfer ◽  
Subsequent Onset

Central to the normal state of cuprate high-temperature superconductors is the collapse of the pseudo-gap, briefly reviewed here, at a critical point and the subsequent onset of the strange metal characterized by a resistivity that scales linearly with temperature. A possible clue to the resolution of this problem is the inter-relation between two facts: (i) a robust theory of T -linear resistivity resulting from quantum criticality requires an additional length scale outside the standard one-parameter scaling scenario and (ii) breaking the Landau correspondence between the Fermi gas and an interacting system with short-range repulsions requires non-fermionic degrees. We show that a low-energy theory of the Hubbard model that correctly incorporates dynamical spectral weight transfer has the extra degrees of freedom needed to describe this physics. The degrees of freedom that mix into the lower band as a result of dynamical spectral weight transfer are shown to either decouple beyond a critical doping, thereby signalling Mottness collapse, or unbind above a critical temperature, yielding strange metal behaviour characterized by T -linear resistivity.

STABLE hc/e VORTICES IN SUPERCONDUCTORS WITH SPIN-CHARGE SEPARATION

1992 ◽  
Vol 06 (05n06) ◽  
pp. 509-526
Author(s):  
Subir Sachdev
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Normal State ◽  
Phenomenological Model ◽  
Charge Separation ◽  
Cuprate Superconductors ◽  
Superconducting Phase ◽  
Low Energy ◽  
Large N ◽  
Normal State Properties

A phenomenological model, F, of the superconducting phase of systems with spin-charge separation and antiferromagnetically induced pairing is studied. Above Hc1, magnetic flux can always pierce the superconductor in vortices with flux hc/2e, but regimes are found in which vortices with flux hc/e are preferred. Little-Park and other experiments, which examine periodicities with a varying magnetic field, always observe a period of hc/2e. The low energy properties of a symplectic large-N expansion of a model of the cuprate superconductors are argued to be well described by F. This analysis and some normal state properties of the cuprates suggest that hc/e vortices should be stable at the lowest dopings away from the insulating state at which superconductivity first occurs.

scholarly journals The UV fate of anomalous U(1)s and the Swampland

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Nathaniel Craig ◽  
Isabel Garcia Garcia ◽  
Graham D. Kribs
Keyword(s):  
Quantum Gravity ◽  
Gauge Theories ◽  
Critical Size ◽  
Gauge Coupling ◽  
Low Energy ◽  
Gravitational Anomaly ◽  
Light Vector ◽  
Energy Theory ◽  
The Cost ◽  
Weak Gravity

Abstract Massive U(1) gauge theories featuring parametrically light vectors are suspected to belong in the Swampland of consistent EFTs that cannot be embedded into a theory of quantum gravity. We study four-dimensional, chiral U(1) gauge theories that appear anomalous over a range of energies up to the scale of anomaly-cancelling massive chiral fermions. We show that such theories must be UV-completed at a finite cutoff below which a radial mode must appear, and cannot be decoupled — a Stückelberg limit does not exist. When the infrared fermion spectrum contains a mixed U(1)-gravitational anomaly, this class of theories provides a toy model of a boundary into the Swampland, for sufficiently small values of the vector mass. In this context, we show that the limit of a parametrically light vector comes at the cost of a quantum gravity scale that lies parametrically below MP1, and our result provides field theoretic evidence for the existence of a Swampland of EFTs that is disconnected from the subset of theories compatible with a gravitational UV-completion. Moreover, when the low energy theory also contains a U(1)3 anomaly, the Weak Gravity Conjecture scale makes an appearance in the form of a quantum gravity cutoff for values of the gauge coupling above a certain critical size.

scholarly journals NONCOMMUTATIVE OPEN STRING THEORIES AND THEIR DUALITIES

2001 ◽  
Vol 16 (04n06) ◽  
pp. 349-359 ◽  
Author(s):  
M. M. SHEIKH-JABBARI
Keyword(s):  
Open String ◽  
Low Energy ◽  
Duality Group ◽  
Critical Limit ◽  
Quantum Theories ◽  
Open Strings ◽  
Energy Theory ◽  
String Theories

The recently found noncritical open string theories is reviewed. These open strings, noncommutative open string theories (NCOS), arise as consistent quantum theories describing the low energy theory of D-branes in a background electric B-field in the critical limit. Focusing on the D3-brane case, we construct the most general (3+1) NCOS, which is described by four parameters. We study S- and T-dualities of these theories and argue the existence of a U-duality group.

Quantum oscillations in the high- T c cuprates

2011 ◽  
Vol 369 (1941) ◽  
pp. 1687-1711 ◽  
Author(s):  
Suchitra E. Sebastian ◽  
Neil Harrison ◽  
Gilbert G. Lonzarich
Keyword(s):  
Fermi Surface ◽  
Cuprate Superconductors ◽  
Low Energy ◽  
Quantum Oscillation ◽  
Electronic Excitations ◽  
Close Correspondence ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Quantum Oscillations ◽  
Underdoped Cuprates

We review recent progress in the study of quantum oscillations as a tool for uniquely probing low-energy electronic excitations in high- T c cuprate superconductors. Quantum oscillations in the underdoped cuprates reveal that a close correspondence with Landau Fermi-liquid behaviour persists in the accessed regions of the phase diagram, where small pockets are observed. Quantum oscillation results are viewed in the context of momentum-resolved probes such as photoemission, and evidence examined from complementary experiments for potential explanations for the transformation from a large Fermi surface into small sections. Indications from quantum oscillation measurements of a low-energy Fermi surface instability at low dopings under the superconducting dome at the metal–insulator transition are reviewed, and potential implications for enhanced superconducting temperatures are discussed.

Low-energy representation of the projected BCS Hamiltonian close to half filling

2009 ◽  
Vol 79 (11) ◽  
Author(s):  
Evgueny Kochetov ◽  
Alvaro Ferraz ◽  
Rafael T. Pepino
Keyword(s):  
Low Energy ◽  
Half Filling ◽  
Bcs Hamiltonian

scholarly journals Quantum dynamics of low-energy theory on semilocal non-Abelian strings

2011 ◽  
Vol 84 (6) ◽  
Author(s):  
P. Koroteev ◽  
M. Shifman ◽  
W. Vinci ◽  
A. Yung
Keyword(s):  
Quantum Dynamics ◽  
Low Energy ◽  
Energy Theory
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