Laser Physics and Quantum Optics Project
Visitors in 1998
Susana will give a talk in the HIP seminar series (basement lecture room) on Tuesday Feb. 3 at 10.15:
Title: Improved frequency standards using quantum entanglement
The optimal precision of frequency measurements is discussed, both in ideal and noisy conditions. We analyze different preparations of two-level systems as well as different measurement procedures. It will shown that standard Ramsey spectroscopy on uncorrelated atoms and optimal measurements on maximally entangled states provide the same resolution. The best accuracy is achieved using partially entangled states with a high degree of symmetry.
Martin will give a talk in the HIP seminar series (old TFT lecture room) on Thursday Feb. 5 at 10.15:
Title: Entanglement in Quantum Information Theory
Initially it was thought that quantum entanglement manifests itself only in the violation of Bell inequalities and is therefore only of use in fundamental tests of quantum mechanics. In this talk I will show that there is more to entanglement. Entangled states have developed into fundamental tools used in quantum information theory which allow applications such as quantum state teleportation or secure quantum cryptography, both of which can be implemented experimentally.
He will give a talk in the HIP seminar series (basement lecture room) on Tuesday May 12 at 10.15:
Title: Counterintuitive Techniques for Pulsed Laser Population Transfer
During the last decade a class of techniques has become available for inducing complete population transfer between excited states of atoms or molecules. In simplest form the procedure uses a stimulated Raman-type coupling in which the Stokes pulse (coupling the desired target state to an intermediate state) occurs before the pump pulse (coupling the initial state to the intermediate state). The pulse ordering reverses the intuitive order used with incoherent excitation. The success of the stimulated Raman adiabatic passage (STIRAP) depends on the creation and retention of an optical coherence with the Stokes pulse -- the creation of a population trapping state. I will discuss some of the numerous theoretical and experimental extensions of the simple concept, which has application not only to the preparation of selected rotational-vibrational states of molecules but also to quantum optics and the preparation of specialized photon states.
He will give a talk in the HIP seminar series (HIP Seminar Room) on Friday September 11 at 10.15:
Title: Coherently Driven Dynamics in Atoms: Suppression of Ionization and Novel Atom Optics Elements
Coherent radiation has become a versatile tool for the manipulation of atomic and molecular states and processes. After a brief review of the basic concept of coherent population transfer, emphasizing the relevance of trapped state formation and exemplifying it by experimental data, the use of such concept to control processes will be discussed. Specifically, recent results about very pronounced laser-induced continuum structure (LICS) in the ionization of He-atoms out for one of their metastable states will be presented. Furthermore, the flexibility gained will be demonstrated using the experimentally realized laser-induced dissipation-free deflection of atoms and a variable matter wave beam splitter as an example.
Dagmar will give a talk in the HIP seminar series (basement lecture room) on Tuesday September 29 at 10.15:
Title: How far can we go with quantum cloning?
In the context of quantum information theory and quantum computation some fundamental issues of quantum mechanics have recently received increasing interest, one of them being quantum cloning. Perfect copying of an unknown quantum state is impossible, due to unitarity and linearity of quantum mechanics (no-cloning theorem). I will discuss the possibility of imperfect quantum cloning and show which upper limit for the quality of the copies can be reached. The optimal cloning transformation depends on the scenario (e.g. state-dependent versus state-independent cloning, number of given inputs and created outputs). The connection to quantum state estimation will also be explained.