# Other Physics Papers

### Quantum Interrogation and the Safer X-ray (February 2001)

(Adrian Kent and David Wallace) Online only; cite as arxiv:quant-ph/0102118.

We investigate quantum interrogation techniques which allow imaging information about semi-transparent objects to be obtained with lower absorption rates than standard classical methods. We show that a gain proportional to log N can be obtained when searching for defects in an array of N pixels, if it is known that at most M of the pixels can have transparencies different from a predetermined theoretical value. A logarithmic gain can also be obtained when searching for infrequently occurring large structures in arrays.

### Simple computer model for the quantum Zeno effect (April 2000)

*Physical Review A* 63 (2001), 022019

This paper presents a simple model for repeated measurement of a quantum system: the evolution of a free particle, simulated by discretising the particle's position. This model is easily simulated by computer and provides a useful arena to investigate the effects of measurement upon dynamics, in particular the slowing of evolution due to measurement (the `quantum Zeno effect'). The results of this simulation are discussed for two rather different sorts of measurement process, both of which are (simplified forms of) measurements used in previous simulations of position measurement. A number of interesting results due to measurement are found, and the investigation casts some light on previous disagreements about the presence or absence of the Zeno effect.

- PDF of published version (requires subscription)
- Preprint PDF