Browsing by Author "Tempel, David"
Now showing items 1-13 of 13
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Computational Complexity of Time-Dependent Density Functional Theory
Whitfield, J; Yung, M-H; Tempel, David Gabriel; Boixo, S; Aspuru-Guzik, Alan (IOP Publishing, 2014)Time-dependent density functional theory (TDDFT) is rapidly emerging as a premier method for solving dynamical many-body problems in physics and chemistry. The mathematical foundations of TDDFT are established through the ... -
A Correlated-Polaron Electronic Propagator: Open Electronic Dynamics beyond the Born-Oppenheimer Approximation
Parkhill, John; Markovich, Thomas Lee; Tempel, David Gabriel; Aspuru-Guzik, Alan (American Institute of Physics, 2012)In this work, we develop an approach to treat correlated many-electron dynamics, dressed by the presence of a finite-temperature harmonic bath. Our theory combines a small polaron transformation with the second-order ... -
Exciton Coherence Lifetimes from Electronic Structure
Parkhill, John Anthony; Tempel, David Gabriel; Aspuru-Guzik, Alan (American Institute of Physics, 2012-04-06)We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles. Our results shed light on whether commonly used models of the bath calculated via detailed ... -
Introduction to Quantum Algorithms for Physics and Chemistry
Yung, Man hong; Whitfield, James D; Boixo, Sergio; Tempel, David Gabriel; Aspuru-Guzik, Alan (John Wiley & Sons, 2013-09-20)An enormous number of model chemistries are used in computational chemistry to solve or approximately solve the Schr odinger equation; each with their own drawbacks. One key limitation is that the hardware used in ... -
The Kitaev–Feynman Clock for Open Quantum Systems
Tempel, David; Aspuru-Guzik, Alan (IOP Publishing, 2014)We show that Kitaevʼs construction of Feynmanʼs clock, in which the time-evolution of a closed quantum system is encoded as a ground state problem, can be extended to open quantum systems. In our formalism, the ground ... -
Open Quantum Systems: Density Matrix Formalism and Applications
Aspuru-Guzik, Alan; Tempel, David Gabriel; Yuen-Zhou, Joel (Springer, 2012)In its original formulation, TDDFT addresses the isolated dynamics of electronic systems evolving unitarily (Runge and Gross 1984). However, there exist many situations in which the electronic degrees of freedom are not ... -
Quantum Computing Without Wavefunctions: Time-Dependent Density Functional Theory for Universal Quantum Computation
Tempel, David Gabriel; Aspuru-Guzik, Alan (Nature Publishing Group, 2012)We prove that the theorems of TDDFT can be extended to a class of qubit Hamiltonians that are universal for quantum computation. The theorems of TDDFT applied to universal Hamiltonians imply that single-qubit expectation ... -
Relaxation and Dephasing in Open Quantum Systems Time-Dependent Density Functional Theory: Properties of Exact Functionals from an Exactly-Solvable Model System
Tempel, David Gabriel; Aspuru-Guzik, Alán (Elsevier, 2011)The dissipative dynamics of many-electron systems interacting with a thermal environment has remained a long-standing challenge within time-dependent density functional theory (TDDFT). Recently, the formal foundations of ... -
The role of interparticle interaction and environmental coupling in a two-particle open quantum system
Laguna, Humberto G.; Sagar, Robin P.; Tempel, David; Aspuru-Guzik, Alan (Royal Society of Chemistry (RSC), 2016)The effects of bath coupling on an interacting two-particle quantum system are studied using tools from information theory. Shannon entropies of the one (reduced) and two-particle distribution functions in position, momentum ... -
Theory of Excitation Broadening Using Time-Dependent Density Functional Theory for Open Quantum Systems
Tempel, David G.; Aspuru-Guzik, Alan (2010)The Casida equations of linear response TDDFT are extended to calculate linear spectra of open quantum systems evolving according to a Markovian master equation. By mapping a many-body open quantum system onto an open, ... -
Time-Dependent Density Functional Theory for Open Quantum Systems and Quantum Computation
Tempel, David Gabriel (2012-08-10)First-principles electronic structure theory explains properties of atoms, molecules and solids from underlying physical principles without input from empirical parameters. Time-dependent density functional theory (TDDFT) ... -
Time-Dependent Density Functional Theory for Open Quantum Systems with Unitary Propagation
Yuen-Zhou, Joel; Tempel, David Gabriel; Rodríguez-Rosario, César A.; Aspuru-Guzik, Alan (The American Physical Society, 2010)We extend the Runge-Gross theorem for a very general class of open quantum systems under weak assumptions about the nature of the bath and its coupling to the system. We show that for Kohn-Sham (KS) time-dependent density ... -
Time-Dependent Density Functional Theory of Open Quantum Systems in the Linear-Response Regime
Tempel, David Gabriel; Watson, Mark A.; Olivares-Amaya, Roberto; Aspuru-Guzik, Alán (American Institute of Physics, 2011)Time-dependent density functional theory (TDDFT) has recently been extended to describe many-body open quantum systems evolving under nonunitary dynamics according to a quantum master equation. In the master equation ...