--- title: "\"A Deformed Model for the Unstable Phonon Spectrum in 4He • CBPF Index" description: "CBPF INDEX is the system that tracks the scientific and technological output of CBPF. It lists the articles, books, technical reports and other publications of the whole CBPF community." canonical_url: "https://index.cbpf.br/en/publicacoes/6ad2a767639f62b11adbb87a" locale: en meta: "og:description": "CBPF INDEX is the system that tracks the scientific and technological output of CBPF. It lists the articles, books, technical reports and other publications of the whole CBPF community." "og:image": "https://index.cbpf.br/_og/d/c_Item%2Ctitulo_~IkEgRGVmb3JtZWQgTW9kZWwgZm9yIHRoZSBVbnN0YWJsZSBQaG9ub24gU3BlY3RydW0gaW4gPG1hdGg-NEhlPC9tYXRoPg%2Ctipo_Physics%2BNote%2Ccor_~I2E4MmMwMA%2Cautores_~TWFyY28gQXVyw6lsaW8gZG8gUmVnbyBNb250ZWlybzsgTMOtZ2lhIE1hcmlhIENvZWxobyBkZSBTb3V6YSBSb2RyaWd1ZXM7IFN0ZW5pbyBXdWxjaw%2Cdetalhe_1996%2Csecao_Publications%2Cp_Ii9lbi9wdWJsaWNhY29lcy82YWQyYTc2NzYzOWY2MmIxMWFkYmI4N2Ei%2Cs_deMqmQlh5e-oo1DJ.png" "og:image:height": "600" "og:image:type": image/png "og:image:width": "1200" "og:title": "\"A Deformed Model for the Unstable Phonon Spectrum in 4He • CBPF Index" "twitter:image": "https://index.cbpf.br/_og/d/c_Item%2Ctitulo_~IkEgRGVmb3JtZWQgTW9kZWwgZm9yIHRoZSBVbnN0YWJsZSBQaG9ub24gU3BlY3RydW0gaW4gPG1hdGg-NEhlPC9tYXRoPg%2Ctipo_Physics%2BNote%2Ccor_~I2E4MmMwMA%2Cautores_~TWFyY28gQXVyw6lsaW8gZG8gUmVnbyBNb250ZWlybzsgTMOtZ2lhIE1hcmlhIENvZWxobyBkZSBTb3V6YSBSb2RyaWd1ZXM7IFN0ZW5pbyBXdWxjaw%2Cdetalhe_1996%2Csecao_Publications%2Cp_Ii9lbi9wdWJsaWNhY29lcy82YWQyYTc2NzYzOWY2MmIxMWFkYmI4N2Ei%2Cs_deMqmQlh5e-oo1DJ.png" --- > Index of every page on this site: [llms.txt](https://index.cbpf.br/llms.txt) **Physics Note****Published** # **"A Deformed Model for the Unstable Phonon Spectrum in **4He\^4He\4He **Marco Aurélio do Rego Monteiro; Lígia Maria Coelho de Souza Rodrigues; Stenio Wulck** 1996 [**Download PDF **0.5 MB](https://index.cbpf.br/files/publicacao/6ad2a767639f62b11adbb87a/pdf) [**Contact owner**](mailto:apub@cbpf.br?subject=%22A%20Deformed%20Model%20for%20the%20Unstable%20Phonon%20Spectrum%20in%20%3Cmath%3E4He%3C%2Fmath%3E) ## **Publication details**
Authors
Marco Aurélio do Rego Monteiro; Lígia Maria Coelho de Souza Rodrigues; Stenio Wulck
Type
Physics Note
Status
Published
Publication date
1996
Description
The theoretical derivation of the phonon anomalous dispersion relation, \linebreak <math>w^{ph} = c_0 p (1-\gamma p^2)\,\!</math>, predicts that <math>\gamma\,\!</math> is positive and therefore that the four-phonon process is the dominant scattering, thus contradicting experimental results of phonon lifetime in neutron scattering and of specific heat measurements. We show that this discrepancy between theory and experiment concerning the stability of phonon spectrum is overcome when we treat the gas of phonon excitations in <math>^4He\,\!</math> as an ideal deformed bosonic gas. When this model is compared with data from <math>^4He\,\!</math> specific heat measurements for <math>T<1\ K\,\!</math>, it reproduces within <math>5%\,\!</math> of accuracy the curves resulting from least-squares fits of those data.
Year
1996
Number
CBPF-NF-025/96
Linked to a thesis
No
Linked to a grant
No
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