Browsing by Author "Tempel, David"
Now showing items 113 of 13

Computational Complexity of TimeDependent Density Functional Theory
Whitfield, J; Yung, MH; Tempel, David Gabriel; Boixo, S; AspuruGuzik, Alan (IOP Publishing, 2014)Timedependent density functional theory (TDDFT) is rapidly emerging as a premier method for solving dynamical manybody problems in physics and chemistry. The mathematical foundations of TDDFT are established through the ... 
A CorrelatedPolaron Electronic Propagator: Open Electronic Dynamics beyond the BornOppenheimer Approximation
Parkhill, John; Markovich, Thomas Lee; Tempel, David Gabriel; AspuruGuzik, Alan (American Institute of Physics, 2012)In this work, we develop an approach to treat correlated manyelectron dynamics, dressed by the presence of a finitetemperature harmonic bath. Our theory combines a small polaron transformation with the secondorder ... 
Exciton Coherence Lifetimes from Electronic Structure
Parkhill, John Anthony; Tempel, David Gabriel; AspuruGuzik, Alan (American Institute of Physics, 20120406)We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from firstprinciples. 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; AspuruGuzik, Alan (John Wiley & Sons, 20130920)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; AspuruGuzik, Alan (IOP Publishing, 2014)We show that Kitaevʼs construction of Feynmanʼs clock, in which the timeevolution 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
AspuruGuzik, Alan; Tempel, David Gabriel; YuenZhou, 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: TimeDependent Density Functional Theory for Universal Quantum Computation
Tempel, David Gabriel; AspuruGuzik, 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 singlequbit expectation ... 
Relaxation and Dephasing in Open Quantum Systems TimeDependent Density Functional Theory: Properties of Exact Functionals from an ExactlySolvable Model System
Tempel, David Gabriel; AspuruGuzik, Alán (Elsevier, 2011)The dissipative dynamics of manyelectron systems interacting with a thermal environment has remained a longstanding challenge within timedependent density functional theory (TDDFT). Recently, the formal foundations of ... 
The role of interparticle interaction and environmental coupling in a twoparticle open quantum system
Laguna, Humberto G.; Sagar, Robin P.; Tempel, David; AspuruGuzik, Alan (Royal Society of Chemistry (RSC), 2016)The effects of bath coupling on an interacting twoparticle quantum system are studied using tools from information theory. Shannon entropies of the one (reduced) and twoparticle distribution functions in position, momentum ... 
Theory of Excitation Broadening Using TimeDependent Density Functional Theory for Open Quantum Systems
Tempel, David G.; AspuruGuzik, 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 manybody open quantum system onto an open, ... 
TimeDependent Density Functional Theory for Open Quantum Systems and Quantum Computation
Tempel, David Gabriel (20120810)Firstprinciples electronic structure theory explains properties of atoms, molecules and solids from underlying physical principles without input from empirical parameters. Timedependent density functional theory (TDDFT) ... 
TimeDependent Density Functional Theory for Open Quantum Systems with Unitary Propagation
YuenZhou, Joel; Tempel, David Gabriel; RodríguezRosario, César A.; AspuruGuzik, Alan (The American Physical Society, 2010)We extend the RungeGross 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 KohnSham (KS) timedependent density ... 
TimeDependent Density Functional Theory of Open Quantum Systems in the LinearResponse Regime
Tempel, David Gabriel; Watson, Mark A.; OlivaresAmaya, Roberto; AspuruGuzik, Alán (American Institute of Physics, 2011)Timedependent density functional theory (TDDFT) has recently been extended to describe manybody open quantum systems evolving under nonunitary dynamics according to a quantum master equation. In the master equation ...