Dov Levine | Technion Israel Institute of Technology (original) (raw)
Papers by Dov Levine
Crystals and quasicrystals can be characterized by an order that is a purely geometric property o... more Crystals and quasicrystals can be characterized by an order that is a purely geometric property of an instantaneous configuration, independent of particle dynamics or interactions. Glasses, on the other hand, are ostensibly amorphous arrangements of particles. A natural and long-standing question has been whether they too have, albeit in a hidden way, some form of geometric order. Here we define
Physical Review Letters, 1984
... Philadelphia, Pennsylvania 19104 and Paul Joseph Steinhardt Department of Physics, University... more ... Philadelphia, Pennsylvania 19104 and Paul Joseph Steinhardt Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and IBM Thomas J. Watson Research Laboratory, Yorktown Heights, New York 10598 (Received 2 November 1984) A ...
Physical Review E, 1997
TG Mason 1 , Martin-D. Lacasse 2 , Gary S. Grest 2 , Dov Levine 3 , J. Bibette 4 , and DA Weitz 5... more TG Mason 1 , Martin-D. Lacasse 2 , Gary S. Grest 2 , Dov Levine 3 , J. Bibette 4 , and DA Weitz 5 1 Department of Chemical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 2 Corporate Research Science ... VA Parsegian, RP Rand, NL Fuller, and DC Rau, Meth ...
Physical Review Letters, 2015
Experiments find coherent information transfer through biological groups on length and time scale... more Experiments find coherent information transfer through biological groups on length and time scales distinctly below those on which asymptotically correct hydrodynamic theories apply. We present here a new continuum theory of collective motion coupling the velocity and density fields of Toner and Tu to the inertial spin field recently introduced to describe information propagation in natural flocks of birds. The long-wavelength limit of the new equations reproduces the Toner-Tu theory, while at shorter wavelengths (or, equivalently, smaller damping), spin fluctuations dominate over density fluctuations, and second-sound propagation of the kind observed in real flocks emerges. We study the dispersion relation of the new theory and find that when the speed of second sound is large, a gap in momentum space sharply separates firstfrom second-sound modes. This gap implies the existence of silent flocks, namely, of medium-sized systems across which information cannot propagate in a linear and underdamped way, either under the form of orientational fluctuations or under that of density fluctuations, making it hard for the group to achieve coordination.
Physics of Fluids, 2002
... low-dissipation flow regime, and (iii) a transitional, oscillatory flow regime at intermediat... more ... low-dissipation flow regime, and (iii) a transitional, oscillatory flow regime at intermediate angles ... This behavior for smooth, ordered bases is in complete contrast to a planar base ... T. Pöschel, Granular material flowing down an inclined chute: A molecular dynamics simulation, J ...
Physical review letters, Jan 20, 2015
The properties of the absorbing states of nonequilibrium models belonging to the conserved direct... more The properties of the absorbing states of nonequilibrium models belonging to the conserved directed percolation universality class are studied. We find that, at the critical point, the absorbing states are hyperuniform, exhibiting anomalously small density fluctuations. The exponent characterizing the fluctuations is measured numerically, a scaling relation to other known exponents is suggested, and a new correlation length relating to this ordering is proposed. These results may have relevance to photonic band-gap materials.
Physical review letters, Jan 6, 1992
We discuss the implications of the classical Gauss-Bonnet formula to foam in two and three dimens... more We discuss the implications of the classical Gauss-Bonnet formula to foam in two and three dimensions. For a two-dimensional foam it gives a generalization of the von Neumann law for the coarsening of foams to curved surfaces. As a consequence of this we find that the stability properties of stationary bubbles of such a froth depend on the Gaussian curvature
Physical review letters, Jan 21, 1988
Can commensurate states exist on incommensurate lattices. We introduce and study by simulated ann... more Can commensurate states exist on incommensurate lattices. We introduce and study by simulated annealing a simple 1D model related to flux quantization on superconducting networks or charged particles on a substrate to answer this question. For periodic and quasicrystalline patterns we find a set of low-energy states related to both decimation symmetry and periodicity.
Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 1996
We investigate the elastic properties of small droplets under compression. The compression of a b... more We investigate the elastic properties of small droplets under compression. The compression of a bubble by two parallel plates is solved exactly and it is shown that a lowest-order expansion of the solution reduces to a form similar to that obtained by Morse and Witten. Other systems are studied numerically and results for configurations involving between 2 and 20 compressing planes are presented. It is found that the response to compression depends on the number of planes. The shear modulus is also calculated for common lattices and the stability crossover between f.c.c. and b.c.c. is discussed.
Physical review. B, Condensed matter, Jan 15, 1986
Quasicrystals. I. Definition and structure. Dov Levine and Paul J. Steinhardt Department of Physi... more Quasicrystals. I. Definition and structure. Dov Levine and Paul J. Steinhardt Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396. Received 3 September 1985 In a recent paper, we introduced the concept of quasicrystals [Phys. Rev. Lett. ...
Physical Review B, 1985
Page 1. RAPID COMMUNICATIONS PHYSICAL REVIEW В VOLUME 32, NUMBER 8 15 OCTOBER 1985 Quasicrystals ... more Page 1. RAPID COMMUNICATIONS PHYSICAL REVIEW В VOLUME 32, NUMBER 8 15 OCTOBER 1985 Quasicrystals with arbitrary orientational symmetry Joshua ES Socolar, Paul J. Steinhardt, and Dov Levine Department ...
Physical Review E, 2010
We study charge transport in an ionic solution in a confined nanoscale geometry in the presence o... more We study charge transport in an ionic solution in a confined nanoscale geometry in the presence of an externally applied electric field and immobile background charges. For a range of parameters, the ion current shows non-monotonic behavior as a function of the external ion concentration. For small applied electric field, the ion transport can be understood from simple analytic arguments, which are supported by Monte Carlo simulation. The results qualitatively explain measurements of ion current seen in a recent experiment on ion transport through a DNA-threaded nanopore (D. J. Bonthuis et. al., Phys. Rev. Lett, 97, 128104 (2006)).
Physical Review E, 2003
We investigate the role of friction in compaction and segregation of granular materials by combin... more We investigate the role of friction in compaction and segregation of granular materials by combining Edwards' thermodynamic hypothesis with a simple mechanical model and mean-field based geometrical calculations. Systems of single species with large friction coefficients are found to compact less. Binary mixtures of grains differing in frictional properties are found to segregate at high compactivities, in contrary to granular mixtures differing in size, which segregate at low compactivities. A phase diagram for segregation vs. friction coefficients of the two species is generated. Finally, the characteristics of segregation are related directly to the volume fraction without the explicit use of the yet unclear notion of compactivity.
We have performed numerical studies of dense granular flows on an incline with a rough bottom in ... more We have performed numerical studies of dense granular flows on an incline with a rough bottom in two and three dimensions. This flow geometry produces a constant density profile that satisfies scaling relations of the Bagnold, rather than the viscous, kind. No surface-only flows were observed. The bulk and the surface layer differ in their rheology, as evidenced by the
Physical Review E, 2001
We have performed a systematic, large-scale simulation study of granular media in two-and threedi... more We have performed a systematic, large-scale simulation study of granular media in two-and threedimensions, investigating the rheology of cohesionless granular particles in inclined plane geometries, i.e., chute flows. We find that over a wide range of parameter space of interaction coefficients and inclination angles, a steady state flow regime exists in which the energy input from gravity balances that dissipated from friction and inelastic collisions. In this regime, the bulk packing fraction (away from the top free surface and the bottom plate boundary) remains constant as a function of depth z, of the pile. The velocity profile in the direction of flow vx(z) scales with height of the pile H, according to vx(z) ∝ H α , with α = 1.52 ± 0.05. However, the behavior of the normal stresses indicates that existing simple theories of granular flow do not capture all of the features evidenced in the simulations. 46.55.+d, 45.70.Cc,
Physical Review E, 2002
Based on large-scale, three-dimensional chute flow simulations of granular systems, we uncover st... more Based on large-scale, three-dimensional chute flow simulations of granular systems, we uncover strong analogies between the jamming of the grains and the liquid-glass transition. The angle of inclination theta in the former transition appears as an analog of temperature T in the latter. The transition is manifested in the development of a plateau in the contact normal force distribution P(f) at small forces, the splitting of the second peak in the pair-correlation function g(r), and increased fluctuations of the system energy. The static state also exhibits history dependence, akin to the quench-rate dependence of structural properties of glasses, due to the hyperstaticity of the contact network.
Physical Review E, 2002
We study static packings of frictionless and frictional spheres in three dimensions, obtained via... more We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, in which we vary particle hardness, friction coefficient, and coefficient of restitution. Although frictionless packings of hard spheres are always isostatic (with six contacts) regardless of construction history and restitution coefficient, frictional packings achieve a multitude of hyperstatic packings that depend on system parameters and construction history. Instead of immediately dropping to four, the coordination number reduces smoothly from z=6 as the friction coefficient mu between two particles is increased.
Using both survey data and field research, we investigate the effects of employee involvement pra... more Using both survey data and field research, we investigate the effects of employee involvement practices on outcomes for blue-collar workers in the auto supply industry. Using a variety of measures, we find consistent evidence that these practices raise wages by 3-5%. The causal mechanism linking involvement and wages appears most consistent with efficiency wage theories, and least consistent with compensating differences. With respect to employment stability, we find that employee involvement has a knife-edge character. Plants with intensive programs have larger employment gains, but are also slightly more likely to go out of business. These results are consistent with employee involvement raising quality and productivity, but also increasing fixed costs for liquidity-constrained firms.
The Astrophysical Journal, 1982
An exact formalism is developed for describing cosmological models with strong, long wavelength g... more An exact formalism is developed for describing cosmological models with strong, long wavelength gravitational waves of general polarization, propagating over backgrounds corresponding to Bianchi types I through VII. A new metric which exhibits the appropriate symmetries of two equivalent independent polarizations of gravitational waves is introduced and discussed. The formalism is applied to an empty type I cosmology, and it is shown how the original z-dependent chaotic singularity structure transforms itself into gravitational radiation propagating along the z-axis in a Bianchi I background.
Physical Review Letters, 2000
In this Letter, we show that at low temperatures, zero-point fluctuations of the plasmon modes of... more In this Letter, we show that at low temperatures, zero-point fluctuations of the plasmon modes of two mutually coupled 2-D planar Wigner crystals give rise to a novel long-range attractive force. For the case where the distance d between two planar surfaces is large, this attractive force has an unusual power-law decay, which scales as d −7/2 , unlike other fluctuation-induced forces. Specifically, we note that its range is longer than the "standard" zero-temperature van der Waals interaction. This result may in principle be observed in bilayer electronic systems and provides insight into the nature of correlation effects for highly charged surfaces. 61.20.Qg, 63.22.+m Fluctuation-induced forces are ubiquitous in nature (for a recent review, see ) and constitute an important contribution to the interactions of many condensed matter systems . The classic example is the Casimir effect in which quantum fluctuations of the electromagnetic field between two parallel conducting plates lead to an attractive force between them. In the context of statistical physics, Fisher and de Gennes [4] have suggested that a similar effect also exists at or near the critical point of a system which is confined between two planes. Other examples include colloid particles immersed in a critical fluid [5], superfluid films [6], liquid crystals [7], and protein inclusions in fluctuating membranes . In general, fluctuation-induced forces arise because external constraints modify the fluctuations of a correlated medium. These interactions, which are usually longranged, are controlled by thermal fluctuations at finite temperature or quantum fluctuations at low temperature. In this Letter, we present arguments for a longrange attraction, derived from the zero-point fluctuations of the plasmon modes associated with two 2-D Wigner crystals .
Crystals and quasicrystals can be characterized by an order that is a purely geometric property o... more Crystals and quasicrystals can be characterized by an order that is a purely geometric property of an instantaneous configuration, independent of particle dynamics or interactions. Glasses, on the other hand, are ostensibly amorphous arrangements of particles. A natural and long-standing question has been whether they too have, albeit in a hidden way, some form of geometric order. Here we define
Physical Review Letters, 1984
... Philadelphia, Pennsylvania 19104 and Paul Joseph Steinhardt Department of Physics, University... more ... Philadelphia, Pennsylvania 19104 and Paul Joseph Steinhardt Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and IBM Thomas J. Watson Research Laboratory, Yorktown Heights, New York 10598 (Received 2 November 1984) A ...
Physical Review E, 1997
TG Mason 1 , Martin-D. Lacasse 2 , Gary S. Grest 2 , Dov Levine 3 , J. Bibette 4 , and DA Weitz 5... more TG Mason 1 , Martin-D. Lacasse 2 , Gary S. Grest 2 , Dov Levine 3 , J. Bibette 4 , and DA Weitz 5 1 Department of Chemical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 2 Corporate Research Science ... VA Parsegian, RP Rand, NL Fuller, and DC Rau, Meth ...
Physical Review Letters, 2015
Experiments find coherent information transfer through biological groups on length and time scale... more Experiments find coherent information transfer through biological groups on length and time scales distinctly below those on which asymptotically correct hydrodynamic theories apply. We present here a new continuum theory of collective motion coupling the velocity and density fields of Toner and Tu to the inertial spin field recently introduced to describe information propagation in natural flocks of birds. The long-wavelength limit of the new equations reproduces the Toner-Tu theory, while at shorter wavelengths (or, equivalently, smaller damping), spin fluctuations dominate over density fluctuations, and second-sound propagation of the kind observed in real flocks emerges. We study the dispersion relation of the new theory and find that when the speed of second sound is large, a gap in momentum space sharply separates firstfrom second-sound modes. This gap implies the existence of silent flocks, namely, of medium-sized systems across which information cannot propagate in a linear and underdamped way, either under the form of orientational fluctuations or under that of density fluctuations, making it hard for the group to achieve coordination.
Physics of Fluids, 2002
... low-dissipation flow regime, and (iii) a transitional, oscillatory flow regime at intermediat... more ... low-dissipation flow regime, and (iii) a transitional, oscillatory flow regime at intermediate angles ... This behavior for smooth, ordered bases is in complete contrast to a planar base ... T. Pöschel, Granular material flowing down an inclined chute: A molecular dynamics simulation, J ...
Physical review letters, Jan 20, 2015
The properties of the absorbing states of nonequilibrium models belonging to the conserved direct... more The properties of the absorbing states of nonequilibrium models belonging to the conserved directed percolation universality class are studied. We find that, at the critical point, the absorbing states are hyperuniform, exhibiting anomalously small density fluctuations. The exponent characterizing the fluctuations is measured numerically, a scaling relation to other known exponents is suggested, and a new correlation length relating to this ordering is proposed. These results may have relevance to photonic band-gap materials.
Physical review letters, Jan 6, 1992
We discuss the implications of the classical Gauss-Bonnet formula to foam in two and three dimens... more We discuss the implications of the classical Gauss-Bonnet formula to foam in two and three dimensions. For a two-dimensional foam it gives a generalization of the von Neumann law for the coarsening of foams to curved surfaces. As a consequence of this we find that the stability properties of stationary bubbles of such a froth depend on the Gaussian curvature
Physical review letters, Jan 21, 1988
Can commensurate states exist on incommensurate lattices. We introduce and study by simulated ann... more Can commensurate states exist on incommensurate lattices. We introduce and study by simulated annealing a simple 1D model related to flux quantization on superconducting networks or charged particles on a substrate to answer this question. For periodic and quasicrystalline patterns we find a set of low-energy states related to both decimation symmetry and periodicity.
Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 1996
We investigate the elastic properties of small droplets under compression. The compression of a b... more We investigate the elastic properties of small droplets under compression. The compression of a bubble by two parallel plates is solved exactly and it is shown that a lowest-order expansion of the solution reduces to a form similar to that obtained by Morse and Witten. Other systems are studied numerically and results for configurations involving between 2 and 20 compressing planes are presented. It is found that the response to compression depends on the number of planes. The shear modulus is also calculated for common lattices and the stability crossover between f.c.c. and b.c.c. is discussed.
Physical review. B, Condensed matter, Jan 15, 1986
Quasicrystals. I. Definition and structure. Dov Levine and Paul J. Steinhardt Department of Physi... more Quasicrystals. I. Definition and structure. Dov Levine and Paul J. Steinhardt Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396. Received 3 September 1985 In a recent paper, we introduced the concept of quasicrystals [Phys. Rev. Lett. ...
Physical Review B, 1985
Page 1. RAPID COMMUNICATIONS PHYSICAL REVIEW В VOLUME 32, NUMBER 8 15 OCTOBER 1985 Quasicrystals ... more Page 1. RAPID COMMUNICATIONS PHYSICAL REVIEW В VOLUME 32, NUMBER 8 15 OCTOBER 1985 Quasicrystals with arbitrary orientational symmetry Joshua ES Socolar, Paul J. Steinhardt, and Dov Levine Department ...
Physical Review E, 2010
We study charge transport in an ionic solution in a confined nanoscale geometry in the presence o... more We study charge transport in an ionic solution in a confined nanoscale geometry in the presence of an externally applied electric field and immobile background charges. For a range of parameters, the ion current shows non-monotonic behavior as a function of the external ion concentration. For small applied electric field, the ion transport can be understood from simple analytic arguments, which are supported by Monte Carlo simulation. The results qualitatively explain measurements of ion current seen in a recent experiment on ion transport through a DNA-threaded nanopore (D. J. Bonthuis et. al., Phys. Rev. Lett, 97, 128104 (2006)).
Physical Review E, 2003
We investigate the role of friction in compaction and segregation of granular materials by combin... more We investigate the role of friction in compaction and segregation of granular materials by combining Edwards' thermodynamic hypothesis with a simple mechanical model and mean-field based geometrical calculations. Systems of single species with large friction coefficients are found to compact less. Binary mixtures of grains differing in frictional properties are found to segregate at high compactivities, in contrary to granular mixtures differing in size, which segregate at low compactivities. A phase diagram for segregation vs. friction coefficients of the two species is generated. Finally, the characteristics of segregation are related directly to the volume fraction without the explicit use of the yet unclear notion of compactivity.
We have performed numerical studies of dense granular flows on an incline with a rough bottom in ... more We have performed numerical studies of dense granular flows on an incline with a rough bottom in two and three dimensions. This flow geometry produces a constant density profile that satisfies scaling relations of the Bagnold, rather than the viscous, kind. No surface-only flows were observed. The bulk and the surface layer differ in their rheology, as evidenced by the
Physical Review E, 2001
We have performed a systematic, large-scale simulation study of granular media in two-and threedi... more We have performed a systematic, large-scale simulation study of granular media in two-and threedimensions, investigating the rheology of cohesionless granular particles in inclined plane geometries, i.e., chute flows. We find that over a wide range of parameter space of interaction coefficients and inclination angles, a steady state flow regime exists in which the energy input from gravity balances that dissipated from friction and inelastic collisions. In this regime, the bulk packing fraction (away from the top free surface and the bottom plate boundary) remains constant as a function of depth z, of the pile. The velocity profile in the direction of flow vx(z) scales with height of the pile H, according to vx(z) ∝ H α , with α = 1.52 ± 0.05. However, the behavior of the normal stresses indicates that existing simple theories of granular flow do not capture all of the features evidenced in the simulations. 46.55.+d, 45.70.Cc,
Physical Review E, 2002
Based on large-scale, three-dimensional chute flow simulations of granular systems, we uncover st... more Based on large-scale, three-dimensional chute flow simulations of granular systems, we uncover strong analogies between the jamming of the grains and the liquid-glass transition. The angle of inclination theta in the former transition appears as an analog of temperature T in the latter. The transition is manifested in the development of a plateau in the contact normal force distribution P(f) at small forces, the splitting of the second peak in the pair-correlation function g(r), and increased fluctuations of the system energy. The static state also exhibits history dependence, akin to the quench-rate dependence of structural properties of glasses, due to the hyperstaticity of the contact network.
Physical Review E, 2002
We study static packings of frictionless and frictional spheres in three dimensions, obtained via... more We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, in which we vary particle hardness, friction coefficient, and coefficient of restitution. Although frictionless packings of hard spheres are always isostatic (with six contacts) regardless of construction history and restitution coefficient, frictional packings achieve a multitude of hyperstatic packings that depend on system parameters and construction history. Instead of immediately dropping to four, the coordination number reduces smoothly from z=6 as the friction coefficient mu between two particles is increased.
Using both survey data and field research, we investigate the effects of employee involvement pra... more Using both survey data and field research, we investigate the effects of employee involvement practices on outcomes for blue-collar workers in the auto supply industry. Using a variety of measures, we find consistent evidence that these practices raise wages by 3-5%. The causal mechanism linking involvement and wages appears most consistent with efficiency wage theories, and least consistent with compensating differences. With respect to employment stability, we find that employee involvement has a knife-edge character. Plants with intensive programs have larger employment gains, but are also slightly more likely to go out of business. These results are consistent with employee involvement raising quality and productivity, but also increasing fixed costs for liquidity-constrained firms.
The Astrophysical Journal, 1982
An exact formalism is developed for describing cosmological models with strong, long wavelength g... more An exact formalism is developed for describing cosmological models with strong, long wavelength gravitational waves of general polarization, propagating over backgrounds corresponding to Bianchi types I through VII. A new metric which exhibits the appropriate symmetries of two equivalent independent polarizations of gravitational waves is introduced and discussed. The formalism is applied to an empty type I cosmology, and it is shown how the original z-dependent chaotic singularity structure transforms itself into gravitational radiation propagating along the z-axis in a Bianchi I background.
Physical Review Letters, 2000
In this Letter, we show that at low temperatures, zero-point fluctuations of the plasmon modes of... more In this Letter, we show that at low temperatures, zero-point fluctuations of the plasmon modes of two mutually coupled 2-D planar Wigner crystals give rise to a novel long-range attractive force. For the case where the distance d between two planar surfaces is large, this attractive force has an unusual power-law decay, which scales as d −7/2 , unlike other fluctuation-induced forces. Specifically, we note that its range is longer than the "standard" zero-temperature van der Waals interaction. This result may in principle be observed in bilayer electronic systems and provides insight into the nature of correlation effects for highly charged surfaces. 61.20.Qg, 63.22.+m Fluctuation-induced forces are ubiquitous in nature (for a recent review, see ) and constitute an important contribution to the interactions of many condensed matter systems . The classic example is the Casimir effect in which quantum fluctuations of the electromagnetic field between two parallel conducting plates lead to an attractive force between them. In the context of statistical physics, Fisher and de Gennes [4] have suggested that a similar effect also exists at or near the critical point of a system which is confined between two planes. Other examples include colloid particles immersed in a critical fluid [5], superfluid films [6], liquid crystals [7], and protein inclusions in fluctuating membranes . In general, fluctuation-induced forces arise because external constraints modify the fluctuations of a correlated medium. These interactions, which are usually longranged, are controlled by thermal fluctuations at finite temperature or quantum fluctuations at low temperature. In this Letter, we present arguments for a longrange attraction, derived from the zero-point fluctuations of the plasmon modes associated with two 2-D Wigner crystals .