How universal are the low temperature acoustic properties of glasses?

Berret, Jean‐François; Meissner, M.

doi:10.1007/bf01320540

Cited by 163 publications

(184 citation statements)

References 15 publications

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“…Using the earlier experimental results for BK7 26 we get A p ≈ 4.0 · 10 7 s −1 K −3 , which is consistent with the estimate based on the two and three pulse echo experimental data, A echo = 4.66 · 10 7 s −1 K −3 . Some overestimate of the relaxation rate can be due to the small effect of longitudinal part of TLS-phonon interaction and/or dipole-dipole TLS interaction, as noticed above.…”

supporting

confidence: 91%

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Low-temperature dipolar echoes in amorphous dielectrics: Significance of relaxation and decoherence free two-level systems

Burin

Leveritt

Ruyters

et al. 2013

EPL

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The nature of dielectric echoes in amorphous solids at low temperatures is investigated. It is shown that at long delay times the echo amplitude is determined by a small subset of two level systems (TLS) having negligible relaxation and decoherence because of their weak coupling to phonons. The echo decay can then be described approximately by power law time dependencies with different powers at times longer and shorter than the typical TLS relaxation time. The theory is applied to recent measurements of two and three pulse dipolar echo in borosilicate glass BK7 and provides a perfect data fit in the broad time and temperature ranges under the assumption that there exist two TLS relaxation mechanisms due to TLS-phonons and TLS-TLS interaction. This interpretation is consistent with the previous experimental and theoretical investigations. Further experiments verifying the theory predictions are suggested.

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supporting

confidence: 91%

“…For instance, using Ref. 26 one can estimate χ ∼ 0.00042 for a−SiO 2 . Accordingly the interaction stimulated relaxation rate in a−SiO 2 should be smaller than that in BK7 by a factor of 2, which is interesting to verify experimentally.…”

mentioning

confidence: 99%

Low-temperature dipolar echoes in amorphous dielectrics: Significance of relaxation and decoherence free two-level systems

Burin

Leveritt

Ruyters

et al. 2013

EPL

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“…This quadratic strain dependence is also predicted by the above model, which shows that both Γ ν and Γ (2) ϕ scale as cos (6) and (10)]. Table I summarizes the measured tunneling energies ∆, the deformation potentials ∂ε/∂V where V is the applied piezo voltage, and the relaxation times T 1 measured at ε = 0.…”

Section: 2122supporting

confidence: 64%

Rabi noise spectroscopy of individual two-level tunneling defects

et al. 2017

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Understanding the nature of two-level tunneling defects is important for minimizing their disruptive effects in various nano-devices. By exploiting the resonant coupling of these defects to a superconducting qubit, one can probe and coherently manipulate them individually. In this work we utilize a phase qubit to induce Rabi oscillations of single tunneling defects and measure their dephasing rates as a function of the defect's asymmetry energy, which is tuned by an applied strain. The dephasing rates scale quadratically with the external strain and are inversely proportional to the Rabi frequency. These results are analyzed and explained within a model of interacting standard defects, in which pure dephasing of coherent high-frequency (GHz) defects is caused by interaction with incoherent low-frequency thermally excited defects.Since the early 1970's, various experiments over a wide range of amorphous solids revealed a universality in their thermal, acoustic and dielectric properties below 1 K. 1-3In an attempt to account for this universal behavior, the existence of two-level tunneling defects as a generic property in amorphous systems was postulated.4,5 This phenomenological standard tunneling model (STM) explains many of the universal low-temperature properties of the amorphous state of matter.6 However, despite extensive efforts, the exact nature of the two-level systems (TLSs) remains unknown.With the recent progress in fabrication, manipulation, and measurement of quantum devices it became crucial to understand the microscopic nature of the environment responsible for decoherence. There exists abundant experimental evidence that TLS-baths form an ubiquitous source of noise in various devices such as superconducting microwave resonators, 7 single-electron transistors, 8 and nanomechanical resonators.9 In superconducting qubits, TLSs residing in the amorphous tunnel barrier of Josephson junctions were found to constitute a major source of decoherence.10,11 Via their electric dipole moment, TLSs couple to the ac microwave fields in the circuit. 12Whereas this coupling is deleterious from the point of view of qubit operation, it opens up the possibility to use superconducting qubits as tools for detection, manipulation and characterization of individual TLSs. The transfer of an arbitrary quantum state from a superconducting phase qubit to a resonant TLS was first demonstrated by Neeley et al..13 This method was used to probe the coherence times of individual TLSs.13,14 Furthermore, in Ref. 15 it was shown that there exists an effective qubitmediated coupling between TLSs and an externally applied electromagnetic ac field. This effective coupling was utilized to directly control the quantum state of individual TLSs by coherent resonant microwave driving. 16Previously, 17 we measured the Ramsey (free induction decay) and spin-echo pure dephasing rates of individual TLSs in a phase qubit as a function of their asymmetry energy, which was tuned by an applied strain via a piezo actuator.18 Since the mutual longitu...

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“…For the data collection on metallic glasses 13 this yields an average value of 0.49 eV, not too far away from the average value 0.39 of direct measurements of γ t of the socalled low-temperature "tunneling plateau" in the sound absorption of 18 different inorganic glasses 19 . In this field, scientists have always been wondering what kind of mode coordinate would be able to give such a strong coupling.…”

Section: B Soft Potential Modelmentioning

confidence: 78%

“…It is useful to introduce the coordinate x x = √ 2πe c0 (19) which is zero at the structural saddle point and ±π/2 at the two energy minima. From equs.…”

Section: Density Of Gliding-triangle Modesmentioning

confidence: 99%

An atomic mechanism for the boson peak in metallic glasses

Buchenau

Schober

2008

Philosophical Magazine

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The boson peak in metallic glasses is modeled in terms of local structural shear rearrangements. Using Eshelby's solution of the corresponding elasticity theory problem (J. D. Eshelby, Proc. Roy. Soc. A241, 376 (1957)), one can calculate the saddle point energy of such a structural rearrangement. The neighbourhood of the saddle point gives rise to soft resonant vibrational modes. One can calculate their density, their kinetic energy, their fourth order potential term and their coupling to longitudinal and transverse sound waves.

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How universal are the low temperature acoustic properties of glasses?

Cited by 163 publications

References 15 publications

Low-temperature dipolar echoes in amorphous dielectrics: Significance of relaxation and decoherence free two-level systems

Low-temperature dipolar echoes in amorphous dielectrics: Significance of relaxation and decoherence free two-level systems

Rabi noise spectroscopy of individual two-level tunneling defects

An atomic mechanism for the boson peak in metallic glasses

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