Roden, Jan, Eisfeld, Alexander, Wolff, Wolfgang, Strunz, Walter T.
We present a theory that efficiently describes the quantum dynamics of an electronic excitation that is coupled to a continuous, highly structured phonon environment. Based on a stochastic approach...
Quantum Decoherence of Two Qubits (2009)
Helm, Julius, Strunz, Walter T.
It is commonly stated that decoherence in open quantum systems is due to growing entanglement with an environment. In practice, however, surprisingly often decoherence may equally well be described...
Schlesinger, Martin, Mudrich, Marcel, Stienkemeier, Frank, Strunz, Walter T.
Femtosecond pump-probe spectroscopy has been used to study vibrational dynamics of potassium dimers attached to superfluid helium nanodroplets. Comparing the measured data with theoretical results...
Stochastic field equation for the canonical ensemble of a Bose gas (2008)
Heller, Sigmund, Strunz, Walter T.
We present a novel norm preserving stochastic evolution equation for a Bose field. Ensemble averages are quantum expectation values in the canonical ensemble. This numerically very stable equation...
Test of weak measurement on a two- or three-qubit computer (2007)
Brun, Todd A., Diosi, Lajos, Strunz, Walter T.
Current quantum computer technology is sufficient to realize weak measurements and the corresponding concept of weak values. We demonstrate how the weak value anomaly can be tested, along with...
Unversality of decoherence in the macroworld (2007)
Strunz, Walter T., Haake, Fritz, Braun, Daniel
We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...
Universality of Decoherence (2007)
Braun, Daniel, Haake, Fritz, Strunz, Walter T.
We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...
Electron spin tomography through counting statistics: a quantum trajectory approach (2004)
Schaefers, Holger, Strunz, Walter T.
We investigate the dynamics of electron spin qubits in quantum dots. Measurement of the qubit state is realized by a charge current through the dot. The dynamics is described in the framework of the...
Stochastic Schr{\"o}dinger equations for quantum trajectories offer an alternative and sometimes superior approach to the study of open quantum system dynamics. Here we show that recently established...
Decoherence scenarios from micro- to macroscopic superpositions (2002)
Strunz, Walter T., Haake, Fritz
Environment induced decoherence entails the absence of quantum interference phenomena from the macroworld. The loss of coherence between superposed wave packets depends on their separation. The...
Unversality of decoherence in the macroworld (2002)
Strunz, Walter T., Haake, Fritz, Braun, Daniel
We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...
Universality of Decoherence (2000)
Braun, Daniel, Haake, Fritz, Strunz, Walter T.
We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...
Zero temperature correlations in trapped Bose-Einstein condensates (2000)
We introduce a family of correlated trial wave functions for the $N$-particle ground state of an interacting Bose gas in a harmonic trap. For large $N$, the correlations lead to a relative energy...
Quantum trajectories for Brownian motion (1999)
Strunz, Walter T., Diosi, Lajos, Gisin, Nicolas, Yu, Ting
We present the stochastic Schroedinger equation for the dynamics of a quantum particle coupled to a high temperature environment and apply it the dynamics of a driven, damped, nonlinear quantum...
Post-Markov master equation for the dynamics of open quantum systems (1999)
Yu, Ting, Diosi, Lajos, Gisin, Nicolas, Strunz, Walter T.
A systematic first-order correction to the standard Markov master equation for open quantum systems interacting with a bosonic bath is presented. It extends the Markov Lindblad master equation to the...
Royal Road to Coupling Classical and Quantum Dynamics (1999)
Diosi, Lajos, Gisin, Nicolas, Strunz, Walter T.
We present a consistent framework of coupled classical and quantum dynamics. Our result allows us to overcome severe limitations of previous phenomenological approaches, like evolutions that do not...
Non-Markovian quantum state diffusion: Perturbation approach (1999)
Yu, Ting, Diósi, Lajos, Gisin, Nicolas, Strunz, Walter T.
We present a perturbation theory for non-Markovian quantum state diffusion (QSD), the theory of diffusive quantum trajectories for open systems in a bosonic environment [Physical Review {\bf A 58},...
Open system dynamics with non-Markovian quantum trajectories (1998)
Strunz, Walter T, Diosi, Lajos, Gisin, Nicolas
A non-Markovian stochastic Schroedinger equation for a quantum system coupled to an environment of harmonic oscillators is presented. Its solutions, when averaged over the noise, reproduce the...
The non-Markovian stochastic Schrodinger equation for open systems (1997)
Diosi, Lajos, Strunz, Walter T.
We present the non-Markovian generalization of the widely used stochastic Schrodinger equation. Our result allows to describe open quantum systems in terms of stochastic state vectors rather than...
Linear quantum state diffusion for non-Markovian open quantum systems (1996)
We demonstrate the relevance of complex Gaussian stochastic processes to the stochastic state vector description of non-Markovian open quantum systems. These processes express the general...
Detection of space-time fluctuations by a model matter interferometer (1996)
Percival, Ian C., Strunz, Walter T.
In papers on primary state diffusion (Percival 1994, 1995), numerical estimates suggested that fluctuations in the space-time metric on the scale of the Planck time (10^-44s) could be detected using...
Baumert, Thomas, Engel, Volker, Röttgermann, C., Strunz, Walter T., Gerber, Gustav
The motion of a vibrational wave packet in the bound A(^1 \summe^+_u) electronic state of the sodium dimer is detected in a femtosecond pump/probe molecular beam experiment. For short times harmonic...
Baumert, Thomas, Engel, Volker, Röttgermann, C., Strunz, Walter T., Gerber, Gustav
The motion of a vibrational wave packet in the bound A(^1 \summe^+_u) electronic state of the sodium dimer is detected in a femtosecond pump/probe molecular beam experiment. For short times harmonic...