Density matrix theory and computational aspects of quantum dynamics in active medium

Micha, David A.

doi:10.1002/1097-461x(2000)80:3<394::aid-qua9>3.0.co;2-u

Cited by 23 publications

(24 citation statements)

References 52 publications

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“…A different approach is needed when the s ‐region is not at equilibrium or is strongly perturbed by the p ‐region. In this case, an alternative procedure is to partition the physical system into p ‐ and s ‐regions, each one with its own time‐evolving density operator, and each coupled to the other in a selfconsistent description 11, 32. An example will be shown for photodesorption of Co/Cu(001).…”

Section: Dissipative Dynamics From the Reduced Density Operatormentioning

confidence: 99%

Ontogeny of hippocampal corticosteroid receptors: Effects of antenatal glucocorticoids in human and mouse

Noorlander

Graan

Middeldorp

et al. 2006

J of Comparative Neurology

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Women at risk for preterm delivery are treated with synthetic glucocorticoids (GCs) to enhance fetal lung maturation. GCs can bind to two intracellular receptors, the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), which function as transcription factors. Both are highly expressed in the hippocampus. Several studies have focused on adverse side effects of antenatal GC treatment. However, relatively little is known about the ontogeny of GR and MR, especially in human. Therefore, we studied the ontogeny of both receptors in the human and mouse hippocampus and investigated the effects of antenatal dexamethasone (dex) treatment, a synthetic glucocorticoid, on MR and GR mRNA levels during hippocampal development. The results demonstrate that MR mRNA was first expressed in mouse hippocampus at embryonic day (E)15.5, at the timepoint when dex was administered. In contrast, GR mRNA expression was first observed after birth at postnatal day (P)5. However, in the human hippocampus both receptors are expressed at 24 weeks of gestation, when antenatal GCs are administered in clinical practice. Quantitative in situ hybridization demonstrated that MR mRNA levels were reduced only shortly after dex treatment at E16, but were unaffected from E18 onwards. These findings indicate that a single antenatal dex administration at E15.5 transiently affects MR mRNA levels in the mouse hippocampus. No effect of antenatal dex treatment was found on the human hippocampus at the third trimester of pregnancy. These data on the prenatal ontogeny of both corticosteroid receptors in the human hippocampus is important for understanding the significance of fetal glucocorticoid or stress exposure and its potential effects on health and disease.

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Section: Dissipative Dynamics From the Reduced Density Operatormentioning

confidence: 99%

Ontogeny of hippocampal corticosteroid receptors: Effects of antenatal glucocorticoids in human and mouse

Noorlander

Graan

Middeldorp

et al. 2006

J of Comparative Neurology

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“…Examples of physical systems of interest are collision‐induced and photoinduced dynamics of molecules on solid surfaces, and of atoms and molecules in clusters. In our work, we have made use of density matrices to describe the photodesorption of diatomics from metal surfaces including dissipative effects, to calculate desorption yields, the time delays detected in femtosecond pulse excitation, and the effect of vibrational motions of adsorbates 10–15, and to predict the effect of chirped light pulses on yields 16. A related subject is the dynamics of electronically excited systems, where electronic motions are quantized and nuclear ones can be approximated as quasi‐classical.…”

Section: Introductionmentioning

confidence: 99%

“…The present treatment elaborates on two descriptions of dissipative phenomena, both of which assume instantaneous dissipation. The first one derives from our treatment in terms of complex‐valued, dissipative potentials 14. It breaks up the open system into a primary (or p‐) region of interest, and a secondary (or s‐) region, and introduces a molecular self‐consistent field (SCF)treatment where both regions are evolving simultaneously under the other's influence.…”

Section: Introductionmentioning

confidence: 99%

“…It breaks up the open system into a primary (or p‐) region of interest, and a secondary (or s‐) region, and introduces a molecular self‐consistent field (SCF)treatment where both regions are evolving simultaneously under the other's influence. We have recently followed this approach in studies of photodesorption in terms of density matrices using both a hamiltonian operator approach and a formalism based on superoperators in Liouville space 10, 14. Introducing standard assumptions about the stochastic nature of the medium 7, 35, it is further possible to derive expressions for dissipative operators in the p‐region, in terms of properties of the s‐region and their coupling.…”

Section: Introductionmentioning

confidence: 99%

“…Introducing standard assumptions about the stochastic nature of the medium 7, 35, it is further possible to derive expressions for dissipative operators in the p‐region, in terms of properties of the s‐region and their coupling. In our work, we have derived expressions for dissipative hamiltonians which allow construction of the density matrix in terms of its amplitudes 10, 14. The second description follows the Lindblad formalism 36–39.…”

Section: Introductionmentioning

confidence: 99%

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Dissipative dynamics in many‐atom systems: A density matrix treatment

Micha

Thorndyke

2002

Int J of Quantum Chemistry

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ABSTRACT:The dynamics of a many-atom system are described in terms of the density operator solution of the Liouville-von Neumann equation, for either isolated or dissipative (open) conditions. The treatment introduces a partial Wigner transform of the density operator of the isolated system or of a primary region of interest, respectively, classifying degrees of freedom as quantal or quasi-classical. A secondary region (the medium) is treated as a stochastic environment leading to a dissipative dynamics of the primary region. Dissipative phenomena are described in terms of dissipative potentials and rate operators. The quantum and quasi-classical degrees of freedom can be identified with the electronic and nuclear variables of a many-atom system to provide a description of electronic rearrangement and excitations during dissipative phenomena. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 90: 759-771, 2002

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Density matrix calculations of gaseous and adsorbate dynamics in electronically excited molecular systems

Micha

2006

Int J of Quantum Chemistry

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This contribution deals with two approaches for localized phenomena in excited many-atom systems. The first approach develops a quantum quasi-classical treatment for the density operator, including all atoms. It is based on a partial Wigner representation and is illustrated with applications to photodissociation of NaI, and to light emission of excited Li interacting with a He cluster. This second application describes the direct dynamics with a time-dependent electronic density matrix, expanded in a basis set of atomic functions. It shows that such an approach can deal with electronically excited manyatom systems involving tens of quantum states and hundreds of classical variables. The second approach makes use of the reduced density operator description for a system in a medium. This allows for dissipative dynamics, which can be instantaneous or delayed. An application is presented for femtosecond photodesorption using a Markovian dissipation and construction of the density operator from density amplitudes, for CO/Cu(001). A second application of a reduced density operator has been made to vibrational relaxation of adsorbates, solving integrodifferential equations to compare delayed, instantaneous, and Markovian dissipation. It is concluded that delayed dissipation is needed at short times and that a Markovian treatment is suitable for the interpretation of cross-sectional measurements that involve long-term dynamics.

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Density matrix theory and computational aspects of quantum dynamics in active medium

Cited by 23 publications

References 52 publications

Ontogeny of hippocampal corticosteroid receptors: Effects of antenatal glucocorticoids in human and mouse

Ontogeny of hippocampal corticosteroid receptors: Effects of antenatal glucocorticoids in human and mouse

Dissipative dynamics in many‐atom systems: A density matrix treatment

Density matrix calculations of gaseous and adsorbate dynamics in electronically excited molecular systems

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