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Full-Text Articles in Physics
Using Refraction Caustics To Monitor Evaporation Of Liquid Drop Lenses, James A. Lock, Jearl D. Walker, James H. Andrews
Using Refraction Caustics To Monitor Evaporation Of Liquid Drop Lenses, James A. Lock, Jearl D. Walker, James H. Andrews
Physics Faculty Publications
Irregularities in the perimeter of a water droplet adhering to a vertical pane of glass cause perturbations in the curvature of the droplet surface. When laser light passes through such a droplet, the perturbations produce a far field refraction caustic, which is a section of the caustic known as the parabolic umbilic in the catastrophe theory classification. As the water evaporates and the droplet surface curvature changes, the section of the parabolic umbilic caustic on the viewing screen also changes. We determine the evolution of curvature of the droplet surface by observing the evolution of the far field caustic and …
Quantum-Mechanical Harmonic Chain Attached To Heat Baths Ii: Nonequilibrium Properties, Ulrich Zürcher, Peter Talkner
Quantum-Mechanical Harmonic Chain Attached To Heat Baths Ii: Nonequilibrium Properties, Ulrich Zürcher, Peter Talkner
Physics Faculty Publications
We study nonequilibrium properties of a one-dimensional harmonic chain to whose ends independent heat baths are attached which are kept at different temperatures. Using the quantum Langevin equation approach, we determine the stationary nonequilibrium state for arbitrary temperatures and coupling strength to the heat baths. This allows us to discuss several typical nonequilibrium properties. We find that the heat flux through the chain is finite as the length of the chain goes to infinity, i.e., we recover the well-known fact that the lattice thermal conductivity of the perfect harmonic chain is infinite. In the quantal case, the heat flux jqm …
Quantum-Mechanical Harmonic Chain Attached To Heat Baths I: Equilibrium Properties, Ulrich Zürcher, Peter Talkner
Quantum-Mechanical Harmonic Chain Attached To Heat Baths I: Equilibrium Properties, Ulrich Zürcher, Peter Talkner
Physics Faculty Publications
Starting from quantum Langevin equations for operators we study thermal properties of a one-dimensional harmonic chain to whose ends independent heat baths are attached. In this paper, we mainly discuss the thermal equilibrium state that the chain eventually approaches if the heat baths are at equal temperatures. In the classical limit, this state is determined by the Gibbs ensemble of the free chain, whereas in the quantal case, this is only true if the strength of coupling between chain and heat baths is made infinitely small. We find that corrections for finite coupling strength are appreciable only in boundary layers …
Random-Field Blume-Capel Model: Mean-Field Theory, Miron Kaufman, M. Kanner
Random-Field Blume-Capel Model: Mean-Field Theory, Miron Kaufman, M. Kanner
Physics Faculty Publications
The global phase diagram of the Blume-Capel model in a random field obeying the bimodal symmetric distribution is determined by using the mean-field method. The phase diagram includes an isolated ordered critical end point and two lines of tricritical points. A new phase emerges for strong enough random fields: the ferromagnetic-nonmagnetic phase. It is argued that such a phase occurs in three dimensions.
Interference Enhancement Of The Internal Fields At Structural Scattering Resonances Of A Coated Sphere, James A. Lock
Interference Enhancement Of The Internal Fields At Structural Scattering Resonances Of A Coated Sphere, James A. Lock
Physics Faculty Publications
We examine the interior electromagnetic energy density of a coated nonabsorbing sphere at a number of scattering resonances. As is the case for an uncoated sphere, the interior energy density becomes large at the apl and bpl resonances. It becomes especially large for p - 1 values of the coating thickness at resonance. These p - 1 enhancements are analogous to the interference maxima that occur in the intensity reflectance of two thin films in contact.
Polymerization On The Diamond Hierarchical Lattice: The Migdal-Kadanoff Renormalization-Group Scheme, Miron Kaufman, J. E. Touma
Polymerization On The Diamond Hierarchical Lattice: The Migdal-Kadanoff Renormalization-Group Scheme, Miron Kaufman, J. E. Touma
Physics Faculty Publications
The thermodynamics of the equilibrium polymerization model (grand-canonical ensemble of self-avoiding walks) in two dimensions is worked out by means of the Migdal-Kadanoff renormalization-group technique. This method involves renormalization-group flows in an eight-dimensional parameter space. At the critical point the number of relevant fields (positive exponents) is four. The leading exponent value differs by less than 1% from the (presumed) exact value. The results are exact for the polymerization problem defined on the diamond hierarchical lattice. Some results are peculiar to this lattice and are not expected to hold for Bravais lattices. For instance, the polymerized phase (infinite polymerization index) …