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Full-Text Articles in Other Physics

Evolutionary Dynamics Of Bertrand Duopoly, Julian Killingback, Timothy Killingback Jan 2021

Evolutionary Dynamics Of Bertrand Duopoly, Julian Killingback, Timothy Killingback

Computer Science Department Faculty Publication Series

Duopolies are one of the simplest economic situations where interactions between firms determine market behavior. The standard model of a price-setting duopoly is the Bertrand model, which has the unique solution that both firms set their prices equal to their costs-a paradoxical result where both firms obtain zero profit, which is generally not observed in real market duopolies. Here we propose a new game theory model for a price-setting duopoly, which we show resolves the paradoxical behavior of the Bertrand model and provides a consistent general model for duopolies.


Scalable And High-Fidelity Quantum Random Access Memory In Spin-Photon Networks, Kevin C. Chen, Wenhan Dai, Carlos Errando-Herranz, Seth Lloyd, Dirk Englund Jan 2021

Scalable And High-Fidelity Quantum Random Access Memory In Spin-Photon Networks, Kevin C. Chen, Wenhan Dai, Carlos Errando-Herranz, Seth Lloyd, Dirk Englund

Computer Science Department Faculty Publication Series

A quantum random access memory (qRAM) is considered an essential computing unit to enable polynomial speedups in quantum information processing. Proposed implementations include the use of neutral atoms and superconducting circuits to construct a binary tree but these systems still require demonstrations of the elementary components. Here, we propose a photonic-integrated-circuit (PIC) architecture integrated with solid-state memories as a viable platform for constructing a qRAM. We also present an alternative scheme based on quantum teleportation and extend it to the context of quantum networks. Both implementations realize the two key qRAM operations, (1) quantum state transfer and (2) quantum routing, …


Function And Dissipation In Finite State Automata - From Computing To Intelligence And Back, Natesh Ganesh Oct 2019

Function And Dissipation In Finite State Automata - From Computing To Intelligence And Back, Natesh Ganesh

Doctoral Dissertations

Society has benefited from the technological revolution and the tremendous growth in computing powered by Moore's law. However, we are fast approaching the ultimate physical limits in terms of both device sizes and the associated energy dissipation. It is important to characterize these limits in a physically grounded and implementation-agnostic manner, in order to capture the fundamental energy dissipation costs associated with performing computing operations with classical information in nano-scale quantum systems. It is also necessary to identify and understand the effect of quantum in-distinguishability, noise, and device variability on these dissipation limits. Identifying these parameters is crucial to designing …


Emergent Phenomena In Quantum Critical Systems, Kun Chen Jul 2018

Emergent Phenomena In Quantum Critical Systems, Kun Chen

Doctoral Dissertations

A quantum critical point (QCP) is a point in the phase diagram of quantum matter where a continuous phase transition takes place at zero temperature. Low-dimensional quantum critical systems are strongly correlated, therefore hosting nontrivial emergent phenomena. In this thesis, we first address two decades-old problems on quantum critical dynamics. We then reveal two novel emergent phenomena of quantum critical impurity problems. In the first part of the thesis, we address the linear response dynamics of the $(2+1)$-dimensional $O(2)$ quantum critical universality class, which can be realized in the ultracold bosonic system near the superfluid (SF) to Mott insulator (MI) …


Production Of Cosmological Observables During The Inflationary Epoch, Cody Goolsby-Cole Nov 2017

Production Of Cosmological Observables During The Inflationary Epoch, Cody Goolsby-Cole

Doctoral Dissertations

This dissertation proposal explores the production of present day cosmological observables which might have been produced during the inflationary era. The first observable is the current net electric charge of our observable universe produced by charge fluctuations during inflation. Next, we examine the possibility of a signal in the primordial gravitational wave power spectrum produced by a scalar field with a time dependent mass. Finally, we examine primordial magnetic fields produced during inflation through the Ratra model coupling with the Schwinger effect.


Designing Active Granular Squares, Christopher C. Olson Jul 2016

Designing Active Granular Squares, Christopher C. Olson

Masters Theses

The goal of this thesis has been to find a means of i) designing an active square particle, and ii) continuously varying its degree of activity with the objective of understanding the effects of activity on the various phases of granular matter. The motivations, results and limitations of our methods of creating active particles are discussed in this thesis. The applicability of a stochastic model based on the Langevin equation in 2D as well as implications for future experiments are also discussed.


Non-Vacuum Ads Cosmologies And The Approach To Equilibrium Of Entanglement Entropy, Sebastian Fischetti, David Kastor, Jennie Traschen Nov 2014

Non-Vacuum Ads Cosmologies And The Approach To Equilibrium Of Entanglement Entropy, Sebastian Fischetti, David Kastor, Jennie Traschen

David Kastor

We extend standard results for vacuum asymptotically locally AdS (AlAdS) spacetimes, showing that such spacetimes can be constructed as foliations where the induced metric on each hypersurface satisfies Einstein's equation with stress-energy. By an appropriate choice of stress-energy on the hypersurfaces, the resulting AlAdS spacetime satisfies Einstein's equation with a negative cosmological constant and physical stress tensor. We use this construction to obtain AlAdS solutions whose boundaries are FRW cosmologies sourced by a massless scalar field or by a perfect fluid obeying the strong energy condition. We focus on FRW universes that approach Minkowski spacetime at late times, yielding AlAdS …


Biophysical Studies Of Axonal Transport, Leslie Cyle Conway Apr 2014

Biophysical Studies Of Axonal Transport, Leslie Cyle Conway

Doctoral Dissertations

Intracellular transport provides a mechanism by which cellular material, such as organelles, vesicles, and protein, can be actively transported throughout the cell. This process relies on the activity of the cytoskeletal filament, microtubules, and their associated motor proteins. These motors are able to walk along microtubule tracks while carrying cellular cargos to enable the fast, regulated transport of these cargos. In cells, these microtubule filaments act as a binding platform for numerous different motor species as well as microtubule-associated proteins (MAPs). In addition, these filaments often form higher order structures, such as microtubule bundles. How motors navigate such complex, crowded …


Magnetic Fields In An Expanding Universe, David Kastor, Jennie Traschen Mar 2014

Magnetic Fields In An Expanding Universe, David Kastor, Jennie Traschen

David Kastor

We find a solution to 4D Einstein-Maxwell theory coupled to a massless dilaton field describing a Melvin magnetic field in an expanding universe with 'stiff matter' equation of state parameter w=+1. As the universe expands, magnetic flux becomes more concentrated around the symmetry axis for dilaton coupling a<1/3√ and more dispersed for a>1/3√. An electric field circulates around the symmetry axis in the direction determined by Lenz's law. For a=0 the magnetic flux through a disk of fixed comoving radius is proportional to the proper area of the disk. This result disagrees with the usual expectation based on a test magnetic field that this …


Sum Rule For The Adm Mass And Tensions In Planar Ads Spacetimes, Basem M. El-Menoufi, Benjamin Ett, David Kastor, Jennie Traschen Sep 2013

Sum Rule For The Adm Mass And Tensions In Planar Ads Spacetimes, Basem M. El-Menoufi, Benjamin Ett, David Kastor, Jennie Traschen

David Kastor

An asymptotically planar AdS spacetimes is characterized by its ADM mass and tensions. We define an additional ADM charge Q associated with the scaling Killing vector of AdS, show that Q is given by a certain sum over the ADM mass and tensions and that Q vanishes on solutions to the Einstein equation with negative cosmological constant. The sum rule for the mass and tensions thus established corresponds in an AdS/CFT context to the vanishing of the trace of the boundary stress tensor. We also show that an analogous sum rule holds for local planar sources of stress-energy sources in …


Gravitational Wave Production Through Decay Of The Inflaton Into Intermediary Fields During Slow Roll Inflation, Jessica Lauren Cook Sep 2013

Gravitational Wave Production Through Decay Of The Inflaton Into Intermediary Fields During Slow Roll Inflation, Jessica Lauren Cook

Open Access Dissertations

This dissertation looks for possible observable signals of tensor metric perturbations sourced during slow roll inflation from decay of the inflaton field into other intermediary fields. We focus on two main scenarios, one of explosive production of intermediary fields for a short period during inflation and another of prolonged production of vectors due to a derivative coupling of the vectors with the inflaton field. We only find a possible observable signal of tensor perturbations in the second case.


On The Universality Of Inner Black Hole Mechanics And Higher Curvature Gravity, Alejandra Castro, Nima Dehmami, Gaston Giribet, David Kastor Jul 2013

On The Universality Of Inner Black Hole Mechanics And Higher Curvature Gravity, Alejandra Castro, Nima Dehmami, Gaston Giribet, David Kastor

David Kastor

Black holes are famous for their universal behavior. New thermodynamic relations have been found recently for the product of gravitational entropies over all the horizons of a given stationary black hole. This product has been found to be independent of the mass for all such solutions of Einstein-Maxwell theory in d=4,5. We study the universality of this mass independence by introducing a number of possible higher curvature corrections to the gravitational action. We consider finite temperature black holes with both asymptotically flat and (A)dS boundary conditions. Although we find examples for which mass independence of the horizon entropy product continues …


Gravitational Tension And Thermodynamics Of Planar Ads Spacetimes, Basem M. El-Menoufi, Benjamin Ett, David Kastor, Jennie Traschen Jun 2013

Gravitational Tension And Thermodynamics Of Planar Ads Spacetimes, Basem M. El-Menoufi, Benjamin Ett, David Kastor, Jennie Traschen

David Kastor

We derive new thermodynamic relations for asymptotically planar AdS black hole and soliton solutions. In addition to the ADM mass, these spacetimes are characterized by gravitational tensions in each of the planar spatial directions. We show that with planar AdS asymptotics, the sum of the ADM mass and tensions necessarily vanishes, as one would expect from the AdS /CFT correspondence. Each Killing vector of such a spacetime leads to a Smarr formula relating the ADM mass and tensions, the black hole horizon and soliton bubble areas, and a set of thermodynamic volumes that arise due to the non-vanishing cosmological constant. …


Thermodynamic Volumes And Isoperimetric Inequalities For De Sitter Black Holes, Brian P. Dolan, David Kastor, David KubiznˇA´K, Robert B. Mann, Jennie Traschen May 2013

Thermodynamic Volumes And Isoperimetric Inequalities For De Sitter Black Holes, Brian P. Dolan, David Kastor, David KubiznˇA´K, Robert B. Mann, Jennie Traschen

David Kastor

We consider the thermodynamics of rotating and charged asymptotically de Sitter black holes. Using Hamiltonian perturbation theory techniques, we derive three different first law relations including variations in the cosmological constant, and associated Smarr formulas that are satisfied by such spacetimes. Each first law introduces a different thermodynamic volume conjugate to the cosmological constant. We examine the relation between these thermodynamic volumes and associated geometric volumes in a number of examples, including Kerr-dS black holes in all dimensions and Kerr-Newman-dS black holes in D=4. We also show that the Chong-Cvetic-Lu-Pope solution of D=5 minimal supergravity, analytically continued to positive cosmological …


Multibody Interactions In Coarse-Graining Schemes For Extended Systems, S Are, Ma Katsoulakis, P Plechac, L Rey-Bellet Jan 2008

Multibody Interactions In Coarse-Graining Schemes For Extended Systems, S Are, Ma Katsoulakis, P Plechac, L Rey-Bellet

Luc Rey-Bellet

In this paper we address the role of multibody interactions for the coarse-grained approximation of stochastic lattice systems. Such interaction potentials are often not included in coarse-graining schemes, as they can be computationally expensive. The multibody interactions are obtained from the error expansion of the reference measure which is, in many cases, chosen as a Gibbs measure corresponding to a local mean-field approximation. We identify the parameter $\epsilon$ that characterizes the level of approximation and its relation to the underlying interaction potential. The error analysis suggests strategies to overcome the computational costs due to evaluations of multibody interactions by additional …


Ergodic Properties Of Markov Processes, L Rey-Bellet Jan 2006

Ergodic Properties Of Markov Processes, L Rey-Bellet

Luc Rey-Bellet

In these notes we discuss Markov processes, in particular stochastic differential equations (SDE) and develop some tools to analyze their long-time behavior. There are several ways to analyze such properties, and our point of view will be to use systematically Liapunov functions which allow a nice characterization of the ergodic properties. In this we follow, at least in spirit, the excellent book of Meyn and Tweedie [7]. In general a Liapunov function W is a positive function which grows at infinity and satisfies an inequality involving the generator of the Markov process L: roughly speaking we have the implications (α …


Dynamics Of The Dbi Spike Soliton, David Kastor, Jennie Traschen Dec 1999

Dynamics Of The Dbi Spike Soliton, David Kastor, Jennie Traschen

David Kastor

We compare oscillations of a fundamental string ending on a D3-brane in two different settings: (1) a test-string radially threading the horizon of an extremal black D3-brane and (2) the spike soliton of the DBI effective action for a D3-brane. Previous work has shown that overall transverse modes of the test-string appear as l=0 modes of the transverse scalar fields of the DBI system. We identify DBI world-volume degrees of freedom that have dynamics matching those of the test-string relative transverse modes. We show that there is a map, resembling T-duality, between relative and overall transverse modes for the test-string …


U-Duality, D-Branes And Black Hole Emission Rates: Agreements And Disagreements, Fay Dowker, David Kastor, Jennie Traschen Nov 1998

U-Duality, D-Branes And Black Hole Emission Rates: Agreements And Disagreements, Fay Dowker, David Kastor, Jennie Traschen

David Kastor

An expression for the spacetime absorption coefficient of a scalar field in a five dimensional, near extremal black hole background is derived, which has the same form as that presented by Maldacena and Strominger, but is valid over a larger, U-duality invariant region of parameter space and in general disagrees with the corresponding D-brane result. We develop an argument, based on D-brane thermodynamics, which specifies the range of parameters over which agreement should be expected. For neutral emission, the spacetime and D-brane results agree over this range. However, for charged emission, we find disagreement in the `Fat Black Hole' regime, …