PHYSICAL REVIEW LETTERS

Providing rapid publication of short reports of important fundamental research, with coverage of major advances in all aspects of physics and of developments with significant consequences across subdisciplines.

Letters intended for this Journal must be short and self-contained. A description of editorial Policies and Procedures is published annually in the first July issue. Instructions for manuscript preparation are given in the Information for Contributors published in the first issue of each volume. Rules pertaining to allowed length and memos regarding production requirements appear at the end of some issues of the Journal.

Manuscripts should be submitted in quadruplicate to the Editorial Office. Alternatively their computer files, if prepared in an appropriate format, may be submitted electronically . Submission by fax is not appropriate. Submission is a representation that the work is not being considered for publication elsewhere. Authors should provide indexing codes according to PACS--1996 (available on our Web server, via directory, and in print from the Editorial Office). A signed APS copyright-transfer form (to take effect upon publication) must be provided, and should be included with the submission (the transfer form appears at the end of the 26 May 1997 issue of the Journal, and is available on our Web server, via ftp to aps.org, and in print from the Editorial Office). After publication, payment of a fee of $460 for each Letter and $160 for each Comment or Reply is requested from the authors to defray editorial and production expenses; for properly prepared electronic submissions, the fees requested are $380 and $130, respectively. Reprints may be ordered at an additional cost. Proofs are normally sent to authors.

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Physical Review Letters (ISSN: 0031-9007) is published weekly by The American Physical Society. Copyright 1997 by The American Physical Society.