Directly observing squeezed phonon states with femtosecond x-ray diffraction

Johnson, Steve L.; Beaud, Paul; Vorobeva, Ekaterina; Milne, Christopher J.; Murray, Éamonn D.; Fahy, Stephen B.; Ingold, Gerhard

Directly observing squeezed phonon states with femtosecond x-ray diffraction

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Published Version

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Supplementary file 1

Date

2009

Authors

Johnson, Steve L.

Beaud, Paul

Vorobeva, Ekaterina

Milne, Christopher J.

Murray, Éamonn D.

Fahy, Stephen B.

Ingold, Gerhard

Publisher

American Physical Society

Published Version

10.1103/PhysRevLett.102.175503

Abstract

Squeezed states are quantum states of a harmonic oscillator in which the variance of two conjugate variables each oscillate out of phase. Ultrafast optical excitation of crystals can create squeezed phonon states, where the variance of the atomic displacements oscillates due to a sudden change in the interatomic bonding strength. With femtosecond x-ray diffraction we measure squeezing oscillations in bismuth and conclude that they are consistent with a model in which electronic excitation softens all phonon modes by a constant scaling factor.

Keywords

Coherent phonons , Excitation , Solids , Bismuth , Noise , Light|Bi

Citation

Johnson, S. L., Beaud, P., Vorobeva, E., Milne, C. J., Murray, É. D., Fahy, S. and Ingold, G. (2009) 'Directly observing squeezed phonon states with femtosecond x-ray diffraction', Physical Review Letters, 102(17), 175503 (4pp). doi: 10.1103/PhysRevLett.102.175503