scholarly journals Low-energy theory for the Bose-Hubbard model and the normal ground state of bosons

1999 ◽  
Vol 60 (21) ◽  
pp. 14503-14506 ◽  
Author(s):  
Igor F. Herbut
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
Low Energy ◽  
Energy Theory

First-Principles Theory of Cation and Intercalation Ordering in LixCoO2

1997 ◽  
Vol 496 ◽  
Author(s):  
C. Wolverton ◽  
Alex Zunger
Keyword(s):  
Total Energy ◽  
Ground State ◽  
First Principles ◽  
Low Energy ◽  
Intercalation Reaction ◽  
Vacancy Ordering ◽  
Li Batteries ◽  
Energy Theory ◽  
Ground State Structures ◽  
Battery Material

ABSTRACTSeveral types of cation- and vacancy-ordering exist in the LixCoO2 battery material. The ordering patterns are of interest due to the fact that they can control the voltage in rechargeable Li batteries. We present a first-principles total energy theory which can predict both cation-and vacancy-ordering patterns at both zero and finite temperatures. Also, by calculating the energetics of the Li intercalation reaction, this theory can provide first-principles predictions of battery voltages of Lix;CoO2/Li cells. Our calculations allow us to search the entire configurational space to predict the lowest-energy ground state structures, search for large voltage cathodes, explore metastable low-energy states, and extend our calculations to finite temperatures, thereby searching for order-disorder transitions and states of partial disorder.

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 chemical studies in the design of organic metals. III. Odd-alternant hydrocarbons - The phenalenyl (ply) system

1975 ◽  
Vol 28 (11) ◽  
pp. 2343 ◽  
Author(s):  
RC Haddon
Keyword(s):  
Electronic Structure ◽  
Structural Change ◽  
Ground State ◽  
Quantum Chemical ◽  
Low Energy ◽  
Organic Metals ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Alternant Hydrocarbons ◽  
Equilibrium Geometries

The MINDO/3 SCF MO method has been used to investigate the equilibrium geometries, electronic structure and ground state properties of ply and its univalent ions. The results indicate that ply has a low energy of disproportionation and that electron addition or removal leads to little structural change. From an analysis of the results it is concluded that odd-alternant hydrocarbons, and systems based on the ply nucleus in particular, have many of the characteristics which are considered to be important in the design of organic metals and superconductors.

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