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Cavity Induced Shift and Narrowing of the Positronium Lyman-α Transition

D. B. Cassidy, M. W. J. Bromley, L. C. Cota, T. H. Hisakado, H. W. K. Tom, and A. P. Mills, Jr.
Phys. Rev. Lett. 106, 023401 – Published 10 January 2011
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Abstract

We report experiments in which the line shape of the Lyman-alpha (1S2P) transition was measured for positronium (Ps) atoms both inside and outside a porous silica target. The energy interval ΔE for confined atoms was observed to be larger than that of free Ps by 1.26±0.06meV. A configuration interaction calculation yields results that are consistent with our 5nm sample, and suggests that ΔE decreases dramatically for larger cavity diameters. The linewidth of the transition, (0.066±0.004)nm (FWHM), is about half of what one would expect for free Ps at room temperature due to the Dicke line narrowing effect of confinement. Such measurements can be used to determine void sizes in porous films and Ps dynamics therein, and elimination of the Doppler spread of atoms in a porous film could be useful for the efficient excitation of a Ps gas.

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  • Received 8 October 2010

DOI:https://doi.org/10.1103/PhysRevLett.106.023401

© 2011 The American Physical Society

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In tight spaces

Published 10 January 2011

Laser spectroscopy of positronium confined to nanoscale pores is a tool to probe the size of buried cavities and a step toward the long-term goal of a positronium BEC.

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Authors & Affiliations

D. B. Cassidy1, M. W. J. Bromley2, L. C. Cota2, T. H. Hisakado1, H. W. K. Tom1, and A. P. Mills, Jr.1

  • 1Department of Physics and Astronomy, University of California, Riverside, California 92521-0413, USA
  • 2Department of Physics and Computational Science Research Center, San Diego State University, San Diego, California 92182-1233, USA

Comments & Replies

Comment on “Cavity Induced Shift and Narrowing of the Positronium Lyman-α Transition”

D. G. Green and G. F. Gribakin
Phys. Rev. Lett. 106, 209301 (2011)

Cassidy et al Reply:

D. B. Cassidy, M. W. J. Bromley, L. C. Cota, T. H. Hisakado, H. W. K. Tom, and A. P. Mills, Jr.
Phys. Rev. Lett. 106, 209302 (2011)

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Vol. 106, Iss. 2 — 14 January 2011

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