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Transverse Sound in Microfabricated Cavities in the Fermi Liquid and Superfluid States of Helium-3
Transverse Sound in Microfabricated Cavities in the Fermi Liquid and Superfluid States of Helium-3
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211151410
- ISBN
- 9798382762548
- DDC
- 530
- 서명/저자
- Transverse Sound in Microfabricated Cavities in the Fermi Liquid and Superfluid States of Helium-3
- 발행사항
- [Sl] : Northwestern University, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 201 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 85-11, Section: B.
- 주기사항
- Advisor: Halperin, William P.
- 학위논문주기
- Thesis (Ph.D.)--Northwestern University, 2024.
- 초록/해제
- 요약We combine a variety of spectroscopic and computational techniques to study the quantum fluid states of 3He. The bulk of this thesis is dedicated to the search for transverse sound waves that have been theoretically predicted by Landau in the Fermi Liquid state but have never been definitively observed. These sound modes propagate due to the mean-field interaction between the degenerate fermions giving rise to a restoring force for transverse shear. Acoustic cavities can be microfabricated out of a silicon substrate with a micron scale path length that is suitable for direct detection of this sound mode. The interference fringes of these acoustic Fabry-Perot cavities can be used to determine both the real and imaginary parts of the speed of sound. We calibrate these cavities by acoustic spectroscopy in the superfluid state of 3He. We report a null-result in this search as no clear interference fringe has been observed in the Fermi liquid. We provide theoretical justification for why the sound mode may yet exist but simply not directly detectable due to high attenuation.We also develop new simulation code to generate, characterize, and classify anisotropic silica aerogel that have been used to engineer new phases in superfluid 3He. The underlying microstructure of these aerogels were previously not known. The diffusion-limited cluster aggregation simulations have been generalized to allow for anisotropic diffusion. We report the creation of two types of simulated aerogels which we call planar and nematic. These simulations are combined with X-ray data to classify real aerogels, leading to the surprising conclusion that axially stretched aerogel is planar-like while compressed aerogel is nematic-like. The counterintuitive results of the simulation have been used to explain several different observations in superfluid 3He using NMR spectroscopy including the orbital flop transition and the magnetic susceptibility anomaly recently observed.
- 일반주제명
- Condensed matter physics
- 일반주제명
- Physics
- 일반주제명
- Acoustics
- 일반주제명
- Engineering
- 키워드
- Silica aerogel
- 키워드
- Cavity
- 키워드
- Helium-3
- 키워드
- Microfabrication
- 키워드
- Superfluid state
- 키워드
- Transverse sound
- 기타저자
- Northwestern University Physics and Astronomy
- 기본자료저록
- Dissertations Abstracts International. 85-11B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
008250123s2024 us c eng d■001000017161544
■00520250211151410
■006m o d
■007cr#unu||||||||
■020 ▼a9798382762548
■035 ▼a(MiAaPQ)AAI31292687
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aNguyen, Man Dinh.▼0(orcid)0000-0001-9414-6083
■24510▼aTransverse Sound in Microfabricated Cavities in the Fermi Liquid and Superfluid States of Helium-3
■260 ▼a[Sl]▼bNorthwestern University▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a201 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 85-11, Section: B.
■500 ▼aAdvisor: Halperin, William P.
■5021 ▼aThesis (Ph.D.)--Northwestern University, 2024.
■520 ▼aWe combine a variety of spectroscopic and computational techniques to study the quantum fluid states of 3He. The bulk of this thesis is dedicated to the search for transverse sound waves that have been theoretically predicted by Landau in the Fermi Liquid state but have never been definitively observed. These sound modes propagate due to the mean-field interaction between the degenerate fermions giving rise to a restoring force for transverse shear. Acoustic cavities can be microfabricated out of a silicon substrate with a micron scale path length that is suitable for direct detection of this sound mode. The interference fringes of these acoustic Fabry-Perot cavities can be used to determine both the real and imaginary parts of the speed of sound. We calibrate these cavities by acoustic spectroscopy in the superfluid state of 3He. We report a null-result in this search as no clear interference fringe has been observed in the Fermi liquid. We provide theoretical justification for why the sound mode may yet exist but simply not directly detectable due to high attenuation.We also develop new simulation code to generate, characterize, and classify anisotropic silica aerogel that have been used to engineer new phases in superfluid 3He. The underlying microstructure of these aerogels were previously not known. The diffusion-limited cluster aggregation simulations have been generalized to allow for anisotropic diffusion. We report the creation of two types of simulated aerogels which we call planar and nematic. These simulations are combined with X-ray data to classify real aerogels, leading to the surprising conclusion that axially stretched aerogel is planar-like while compressed aerogel is nematic-like. The counterintuitive results of the simulation have been used to explain several different observations in superfluid 3He using NMR spectroscopy including the orbital flop transition and the magnetic susceptibility anomaly recently observed.
■590 ▼aSchool code: 0163.
■650 4▼aCondensed matter physics
■650 4▼aPhysics
■650 4▼aAcoustics
■650 4▼aEngineering
■653 ▼aSilica aerogel
■653 ▼aCavity
■653 ▼aHelium-3
■653 ▼aMicrofabrication
■653 ▼aSuperfluid state
■653 ▼aTransverse sound
■690 ▼a0611
■690 ▼a0605
■690 ▼a0986
■690 ▼a0537
■71020▼aNorthwestern University▼bPhysics and Astronomy.
■7730 ▼tDissertations Abstracts International▼g85-11B.
■790 ▼a0163
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17161544▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
