Depletion of Two-Level Systems in Ultrastable Computer-Generated Glasses

Khomenko, D. P.; Scalliet, Camille; Berthier, Ludovic; Reichman, David R.; Zamponi, Francesco

doi:10.1103/physrevlett.124.225901

Cited by 63 publications

(85 citation statements)

References 63 publications

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“…It is interesting to note that the range of variability observed in Fig. 4, Right appears to be consistent with a very recent study (61) of the depletion of tunneling two-level systems in stable computer glasses, possibly indicating that a subset of the QLMs is associated with tunneling two-level systems (1,2,36,62).…”

Section: Estimating Qlms' Frequency Scale By Pinching a Glasssupporting

confidence: 89%

Pinching a glass reveals key properties of its soft spots

Rainone

Bouchbinder

Lerner

2020

Proc. Natl. Acad. Sci. U.S.A.

104

183

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It is now well established that glasses feature quasilocalized nonphononic excitations—coined “soft spots”—, which follow a universal ω4 density of states in the limit of low frequencies ω. All glass-specific properties, such as the dependence on the preparation protocol or composition, are encapsulated in the nonuniversal prefactor of the universal ω4 law. The prefactor, however, is a composite quantity that incorporates information both about the number of quasilocalized nonphononic excitations and their characteristic stiffness, in an apparently inseparable manner. We show that by pinching a glass—i.e., by probing its response to force dipoles—one can disentangle and independently extract these two fundamental pieces of physical information. This analysis reveals that the number of quasilocalized nonphononic excitations follows a Boltzmann-like law in terms of the parent temperature from which the glass is quenched. The latter, sometimes termed the fictive (or effective) temperature, plays important roles in nonequilibrium thermodynamic approaches to the relaxation, flow, and deformation of glasses. The analysis also shows that the characteristic stiffness of quasilocalized nonphononic excitations can be related to their characteristic size, a long sought-for length scale. These results show that important physical information, which is relevant for various key questions in glass physics, can be obtained through pinching a glass.

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Section: Estimating Qlms' Frequency Scale By Pinching a Glasssupporting

confidence: 89%

Pinching a glass reveals key properties of its soft spots

Rainone

Bouchbinder

Lerner

2020

Proc. Natl. Acad. Sci. U.S.A.

104

183

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“…These glasses, termed as ultrastable glasses, have received much attention due to both their fundamental importance for understanding the nature of glass and their potentials for broad technological applications. [3][4][5][6][7][8][9][10][11][12][13][14][15] In the past decades, more species of ultrastable glasses, including metallic glasses (MGs) 16,17 and polymeric glasses 18 have been fabricated by PVD, as well as Lennard-Jones glasses in computer simulations. 19 In all these works, the general consensus is that the substrate temperature (Tsub) during deposition is a critical variable and the optimal Tsub for creating an ultrastable glass is near the glass transition temperature (Tg), at 0.8~0.9Tg, [16][17][18][19][20][21] associated with the enhanced surface mobility that gives rise to a more relaxed structure.…”

Section: Table Of Contentsmentioning

confidence: 99%

Microscopic Structural Evolution during Ultrastable Metallic Glass Formation

Luo

Zhu

et al. 2021

ACS Appl. Mater. Interfaces

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By decreasing the rate of physical vapor deposition, ZrCuAl metallic glass with improved stability and mechanical performances can be formed. With scanning transmission electron microscopy, we found that the glass deposited at higher rate exhibits a heterogeneous structure with compositional fluctuations at distances of a few nanometers, which gradually disappear on decreasing the deposition rate and eventually a homogeneous, featureless structure is developed approaching ultrastability. This microscopic structural evolution suggests the existence of two dynamical processes: the faster diffusion driven by the kinetic energy of the depositing atoms, which leads to nanoscale compositional fluctuations, and the slower collective rearrangements that equilibrate the deposited atoms and eliminate the compositional and structural heterogeneity.

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“…The issue of tunneling versus barrier-jumping has been at the basis of the anomalous temperature dependence of the specific heats at low temperatures of some glasses, whose state has formed a prototype for that in proteins [32]. This was clarified in [34] [35] by considerations of tunneling in two level systems, which is of importance at low temperatures and there alone [34] [35] [36] [37]. Tunneling in biological molecules was the subject of Colloquium in the late seventies [38], in which the question of phase-conserving versus decohered state outcome of the processes was left unanswered.…”

Section: Sub-conformal Protein Motion: Phased or Decohered?mentioning

confidence: 99%

Quantum States in Templated Biological Processes

Englman¹

2021

OJBIPHY

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Living matter is characterized by its variegated potential energy landscape possessing a proneness to continually absorb externally supplied energy. This enables it to ascend from its momentary energy minimum state to one of its myriad barriers only to subsequently descend to a new minimum with a potentiality to perform new functions or processes, in the while exuding energy (mainly in the form of heat). As in studies of molecular intersystem crossing, the jumping processes are describable in terms of quantum states. In this work we derive the low energy quantum states for those three templated self-assembling processes, self-replication, metabolism and self-repair that are commonly regarded as distinguishing animate from inanimate substance. The outcome of each process is a new, long-living, stable molecular aggregate characterized by its specific conformation, comprising a host of micro-states associated with sub-conformations and patterned upon the template. The provenance of these newly-formed states is obtained here by a unified formalism for all three processes, based on a Hamiltonian, constructed in an abstract Hilbert-space framework, whose essences are bilinear coupling terms in the Hamiltonian between the template and the bath, as well as between the reactants and the bath. Treating these terms by second order perturbation, one finds in low lying quantum states an alignment between the template and the product, somewhat analogous to the Kramers-Anderson superexchange mechanism, with the bath replacing the bridging anion and by exploitation of the decohering due to the randomness of the bath. The idea underlying this work, recurrent in the biological literature and here expressed in a Physics, Hamiltonian framework, is the correlative unity of the whole biological system comprising multiple organs.

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Depletion of Two-Level Systems in Ultrastable Computer-Generated Glasses

Cited by 63 publications

References 63 publications

Pinching a glass reveals key properties of its soft spots

Pinching a glass reveals key properties of its soft spots

Microscopic Structural Evolution during Ultrastable Metallic Glass Formation

Quantum States in Templated Biological Processes

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