Vibrational dynamics and the structure of glasses

Duval, E.; Boukenter, Aziz; Achibat, T.

doi:10.1088/0953-8984/2/51/001

Cited by 315 publications

(213 citation statements)

References 23 publications

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“…4B (22). This peak is commonly called the boson peak; in supercooled fluids, the boson peak arises from damped oscillations of long lived molecular structures (23,24). This peak shifts to lower frequency with increasing cell density; the associated time scale of this peak, τ Ã ¼ 2π∕ω peak , increases from approximately 1 h to 1.6 h, as shown in Fig.…”

Section: Density Of States Within the Confluent Cellmentioning

confidence: 90%

Glass-like dynamics of collective cell migration

Angelini

Hannezo

Trepat

et al. 2011

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

657

667

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Collective cell migration in tissues occurs throughout embryonic development, during wound healing, and in cancerous tumor invasion, yet most detailed knowledge of cell migration comes from single-cell studies. As single cells migrate, the shape of the cell body fluctuates dramatically through cyclic processes of extension, adhesion, and retraction, accompanied by erratic changes in migration direction. Within confluent cell layers, such subcellular motions must be coupled between neighbors, yet the influence of these subcellular motions on collective migration is not known. Here we study motion within a confluent epithelial cell sheet, simultaneously measuring collective migration and subcellular motions, covering a broad range of length scales, time scales, and cell densities. At large length scales and time scales collective migration slows as cell density rises, yet the fastest cells move in large, multicell groups whose scale grows with increasing cell density. This behavior has an intriguing analogy to dynamic heterogeneities found in particulate systems as they become more crowded and approach a glass transition. In addition we find a diminishing self-diffusivity of short-wavelength motions within the cell layer, and growing peaks in the vibrational density of states associated with cooperative cell-shape fluctuations. Both of these observations are also intriguingly reminiscent of a glass transition. Thus, these results provide a broad and suggestive analogy between cell motion within a confluent layer and the dynamics of supercooled colloidal and molecular fluids approaching a glass transition.active matter | cell mechanics | jamming | collective cell dynamics | nonequilibrium T he collective motion of cells within a tissue is a fundamental biological process, both in health and in disease; for example it is essential to embryonic morphogenesis, organ regeneration, and wound repair (1-4). However, while the motion of individual cells is well understood, collective motion of a large number of cells such as in tissues is only understood in specific instances. Moreover, the transition of the motion of single cells to the collective motion of many cells has not been as extensively studied. This transition is well represented by single monolayers of cells; as they become confluent, the motion of the cells becomes increasingly collective, depending on the presence of their neighbors (5). During collective migration within confluent cell layers, cell sheets flow like a fluid yet remain fixed and solidlike at short time scales, with the motion of each cell constrained by the crowding due to its neighbors (5-7). This solid-like character over short times and collective flow over longer times is reminiscent of many crowded particulate systems, which undergo a transition from a supercooled fluid-like state to a glass-like state. By analogy, the collective motion of cells might be described by a similar transition: as cell density rises, neighboring cells restrict the motion of each cell, forcing cells to move in g...

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Section: Density Of States Within the Confluent Cellmentioning

confidence: 90%

Glass-like dynamics of collective cell migration

Angelini

Hannezo

Trepat

et al. 2011

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

657

667

View full text Add to dashboard Cite

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“…Despite decades of work, the origin of BP remains an open question in condensed matter physics and material science [54]. Existing theoretical models explain BP via different mechanisms such as phonon-saddle transition in the energy landscape [55], local vibrational modes of clusters [56], locally favored structures [57], liberation of molecular fragments [58,59], vibrations in anharmonic potentials [60], and anomaly in transverse phonon propagation related to the Ioffe-Regel limit [54]. Exhibiting common features of disordered and amorphous materials [18,19], the VDOS of CSH presents a BP in the THz region as shown in Fig.…”

Section: Vibrational Densities Of Statesmentioning

confidence: 99%

Physical Origins of Thermal Properties of Cement Paste

2015

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Despite the ever-increasing interest in multiscale porous materials, the chemophysical origin of their thermal properties at the nanoscale and its connection to the macroscale properties still remain rather obscure. In this paper, we link the atomic-and macroscopic-level thermal properties by combining tools of statistical physics and mean-field homogenization theory. We begin with analyzing the vibrational density of states of several calcium-silicate materials in the cement paste. Unlike crystalline phases, we indicate that calcium silicate hydrates (CSH) exhibit extra vibrational states at low frequencies (< 2 THz) compared to the vibrational states predicted by the Debye model. This anomaly is commonly referred to as the boson peak in glass physics. In addition, the specific-heat capacity of CSH in both dry and saturated states scales linearly with the calcium-to-silicon ratio. We show that the nanoscale-confining environment of CSH decreases the apparent heat capacity of water by a factor of 4. Furthermore, full thermal conductivity tensors for all phases are calculated via the Green-Kubo formalism. We estimate the mean free path of phonons in calcium silicates to be on the order of interatomic bonds. This satisfies the scale separability condition and justifies the use of mean-field homogenization theories for upscaling purposes. Upscaling schemes yield a good estimate of the macroscopic specific-heat capacity and thermal conductivity of cement paste during the hydration process, independent of fitting parameters.

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“…This boson peak is thought to be the key to understanding abnormal properties of disordered solids, e.g., the glass transition and unusual lowtemperature thermal properties and energy transport in glasses [15][16][17]. The origin of the boson peak, which has been a topic of vigorous debate, seems to be system-or model-dependent and has been related to a variety of elements, e.g., the transverse Ioffe-Regel limit [18,19], locally favored structures [20], local vibration or coherent motion of particle clusters [21,22], the phonon-saddle transition (in the energy landscape) [9], extended soft modes arising from marginal stability [17,23,24], spatial fluctuation of elastic moduli [25,26], breakdown of the continuum approximation on the mesoscopic length scale [27,28], topologically diverse defects of disordered solids [29], and two-level systems [30]. Although no conclusion has been reached regarding whether the boson peak has a universal origin, it has been shown that the boson peak is strongly coupled to the instability of disordered solids [31,32].…”

Section: Introductionmentioning

confidence: 99%

Role of disorder in determining the vibrational properties of mass-spring networks

Nie

Tong

et al. 2017

Front. Phys.

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By introducing four fundamental types of disorders into a two-dimensional triangular lattice separately, we determine the role of each type of disorder in the vibration of the resulting massspring networks. We are concerned mainly with the origin of the boson peak and the connection between the boson peak and the transverse Ioffe-Regel limit. For all types of disorders, we observe the emergence of the boson peak and Ioffe-Regel limits. With increasing disorder, the boson peak frequency ωBP , transverse Ioffe-Regel frequency ω . Therefore, the argument that the boson peak is equivalent to the transverse Ioffe-Regel limit is not general. Our results suggest that both local coordination number and positional disorder are necessary for the argument to hold, which is actually the case for most disordered solids such as marginally jammed solids and structural glasses. We further combine two types of disorders to cause disorder in both the local coordination number and lattice site position. The density of vibrational states of the resulting networks resembles that of marginally jammed solids well. However, the relation between the boson peak and the transverse Ioffe-Regel limit is still indefinite and condition-dependent. Therefore, the interplay between different types of disorders is complicated, and more in-depth studies are required to sort it out.

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Vibrational dynamics and the structure of glasses

Cited by 315 publications

References 23 publications

Glass-like dynamics of collective cell migration

Glass-like dynamics of collective cell migration

Physical Origins of Thermal Properties of Cement Paste

Role of disorder in determining the vibrational properties of mass-spring networks

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