5A2--Theory of the optical parametric oscillator

A formalism for describing optical parametric oscillation is developed. The theory is applied to the derivation of the oscillation threshold condition, power output, the Manley-Rowe conditions, index matching, and frequency tuning

Effects of decoherence on the radiative and squeezing properties in a coherently driven trapped two-level atom

Analysis of the effects of decoherence on the radiative and squeezing properties of a coherently driven two-level atom trapped in a resonant cavity applying the corresponding master equation is presented. The atomic dynamics as well as the squeezing and statistical properties of the emitted radiation are investigated. It is found that the atom stays in the lower energy level more often at steady state irrespective of the strength of the coherent radiation and thermal fluctuations entering the cavity. Moreover, a strong external coherent radiation results the splitting of the line of the emission spectrum, whereas the decoherence broadens the width and significantly decreases the height. It is also found that the emitted radiation exhibits photon anti-bunching, super-Poissonian photon statistics and squeezing, despite the presence of the decoherence which is expected to destroy the quantum features.Comment: 9 pages, 9 figure

The Safety Appliance Act and the FELA: A Plea for Clarification

The aim of this thesis is to analyse and examine the debate on prenatal testing in Western countries, with a special focus on my own country, Sweden. In the near future it might be possible for a pregnant woman to profile the DNA of her foetus with a simple blood test early in pregnancy. This method of prenatal testing – Non Invasive Prenatal Diagnosis (NIPD) – could potentially detect the genetic causes of almost every disease. I will argue that prenatal testing should be offered by society to all pregnant women, not only to those at highest risk of giving birth to children with severe conditions. I will do that from a perspective of reproductive freedom. Furthermore, I will argue that offering prenatal testing for some conditions (such as Downs’s syndrome) and not for others, is conflicting with the autonomous choice of the pregnant woman

Entanglement Swapping: Entangling Atoms That Never Interacted

In this paper we discuss four different proposals of entangling atomic states of particles which have never interacted. The experimental realization proposed makes use of the interaction of Rydberg atoms with a micromaser cavity prepared in either a coherent state or in a superposition of the zero and one field Fock states. We consider atoms in either a three-level cascade or lambda configurationComment: 17 pages and 2 figure

Simple quantum feedback of a solid-state qubit

We propose an experiment on quantum feedback control of a solid-state qubit, which is almost within the reach of the present-day technology. Similar to the earlier proposal, the feedback loop is used to maintain the coherent (Rabi) oscillations in a qubit for an arbitrary long time; however, this is done in a significantly simpler way, which requires much smaller bandwidth of the control circuitry. The main idea is to use the quadrature components of the noisy detector current to monitor approximately the phase of qubit oscillations. The price for simplicity is a less-than-ideal operation: the fidelity is limited by about 95%. The feedback loop operation can be experimentally verified by appearance of a positive in-phase component of the detector current relative to an external oscillating signal used for synchronization.Comment: 5 page