Absence of a quadratic term in the He4 excitation spectrum

Pat R. Roach*, B. M. Abraham, J. B. Ketterson, M. Kuchnir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


By directly measuring the difference in velocity of 30 and 90 MHz sound waves in liquid He4 below 100 mK, we have determined that the elementary excitation spectrum cannot be described by an expression ε(k)=ck(1+α1k+α2k2+) which has a value for α1 that is greater than 0.01 .

Original languageEnglish (US)
Pages (from-to)32-34
Number of pages3
JournalPhysical review letters
Issue number1
StatePublished - 1972

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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