scholarly journals Imaginary-time quantum many-body theory out of equilibrium. II. Analytic continuation of dynamic observables and transport properties

2013 ◽  
Vol 87 (23) ◽  
Author(s):  
Andreas Dirks ◽  
Jong E. Han ◽  
Mark Jarrell ◽  
Thomas Pruschke
Keyword(s):  
Analytic Continuation ◽  
Transport Properties ◽  
Many Body ◽  
Imaginary Time ◽  
Many Body Theory ◽  
Time Quantum ◽  
Body Theory

scholarly journals When “small” terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

2011 ◽  
Vol 2 ◽  
pp. 862-871 ◽  
Author(s):  
Gemma C Solomon ◽  
Justin P Bergfield ◽  
Charles A Stafford ◽  
Mark A Ratner
Keyword(s):  
Transport Properties ◽  
Single Molecule ◽  
Quantum Interference ◽  
Many Body ◽  
Conjugated Molecules ◽  
Many Body Theory ◽  
Hamiltonian Models ◽  
Single Molecule Junctions ◽  
Body Theory ◽  
Multiple Interference

Quantum interference effects offer opportunities to tune the electronic and thermoelectric response of a quantum-scale device over orders of magnitude. Here we focus on single-molecule devices, in which interference features may be strongly affected by both chemical and electronic modifications to the system. Although not always desirable, such a susceptibility offers insight into the importance of “small” terms, such as through-space coupling and many-body charge–charge correlations. Here we investigate the effect of these small terms using different Hamiltonian models with Hückel, gDFTB and many-body theory to calculate the transport through several single-molecule junctions, finding that terms that are generally thought to only slightly perturb the transport instead produce significant qualitative changes in the transport properties. In particular, we show that coupling of multiple interference features in cross-conjugated molecules by through-space coupling will lead to splitting of the features, as can correlation effects. The degeneracy of multiple interference features in cross-conjugated molecules appears to be significantly more sensitive to perturbations than those observed in equivalent cyclic systems and this needs to be considered if such supernodes are required for molecular thermoelectric devices.

THE HUBBARD-STRATONOVICH TRANSFORMATION AND THE HUBBARD MODEL

1991 ◽  
Vol 05 (06n07) ◽  
pp. 937-976 ◽  
Author(s):  
SANDRO SORELLA
Keyword(s):  
Wave Function ◽  
Hubbard Model ◽  
Ground State ◽  
Trial Wave Function ◽  
Many Body ◽  
Imaginary Time ◽  
Many Body Theory ◽  
Straightforward Application ◽  
Ground State Properties ◽  
Body Theory

The Hubbard-Stratonovich transformation allows one to formulate the problem of calculating the ground state properties of a many-body theory as one of sampling a distribution. This distribution is constructed by propagating a trial wave function under the influence of a one-body time-dependent external field. However, a straightforward application of the Hubbard-Stratonovich transformation gives distributions which are not always positive definite for a generic trial wave function. In this work it is rigorously shown that, for the Hubbard model, in many cases the non-positiveness of this distribution is not important for reaching the infinite imaginary time limit, i.e., the ground state properties.

On the many-body theory of nuclear reactions

1968 ◽  
Vol 111 (1) ◽  
pp. 392-416 ◽  
Author(s):  
K DIETRICH ◽  
K HARA
Keyword(s):  
Nuclear Reactions ◽  
Many Body ◽  
Many Body Theory ◽  
The Many ◽  
Body Theory

MANY-BODY THEORY FOR HYPERFINE EFFECTS IN ATOMS AND MOLECULES

1970 ◽  
Vol 31 (C4) ◽  
pp. C4-99-C4-104
Author(s):  
T. P. DAS ◽  
C. M. DUTTA ◽  
N. C. DUTTA
Keyword(s):  
Many Body ◽  
Atoms And Molecules ◽  
Many Body Theory ◽  
Body Theory

Test of closure approximations in equilibrium classical many‐body theory

1988 ◽  
Vol 88 (12) ◽  
pp. 7791-7798 ◽  
Author(s):  
Leslie J. Root ◽  
Frank H. Stillinger ◽  
Gary E. Washington
Keyword(s):  
Many Body ◽  
Many Body Theory ◽  
Closure Approximations ◽  
Body Theory
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