598 Emergent States of Matter

Term essays Fall 2004

Author Man-Hong Yung

Title: Quantum Entanglement in Many-body Systems


This article is intended to be a pedagogical review of the recent studies of quantum entanglement in many-body systems. The basic concepts of entanglement for pure and mixed states are introduced in an intuitive approach. We will see that in the weakly in- teracting BEC and BCS superconductivity theories, the pair of particles with momentum k and -k are entangled but they are not correlated with other pairs. The entanglement vanishes when the interactions go to zero. The debates on the possible relationship be- tween quantum phase transition and quantum entanglement is mentioned. My personal perspective on this issue is discussed and illustrated with a simple example.

Author: Shiladitya Chakraborty

Title: The superfluid phases of  He


In this essay we shall discuss some of the physical properties of the superfluid phases of  He obtained at ultra low temperatures of a few mK and zero magnetic field.

Author: Harini Barath


Abstract: The phenomenon of Non-Classical Rotational Inertia, in which a body does not rotate with its rotating container, has been recently observed in solid Helium-4. This property is shared by superfluid liquid helium. The recent findings might be evidence of superflow in solids. Superfluidity or flow sans dissipation is commonly associated with liquids. Counter-intuitive as it may seem, quantum mechanics allows for a solid to exhibit superflow too.

Author: Roberto Lambert-Garrido

Title: Analogue of Hawking Radiation in a BEC.


This paper explores the possibility of observing the analogue of a black hole and Hawking radiation in a BEC.

Author : Stefanos Papanikolaou

Title: Spin-Charge separation in Polyacetylene


This essay describes the experimental observations that led to the formulation of the SSH soliton model of polyacetylene's behavior. The basic aspects of this model are presented and its connections with the emergent effect of electron fractionalization are emphasized.

Author: Minjung Kim

Title: Structural, electric, and magnetic properties of Mn perovskites


This paper covers theoretical and experimental investigations on the strongly correlated systems laying stress on the manganese oxide as a good example.

Author: Nicholas Guttenberg

Title: Oscillons in Driven Granular Systems


This essay gives an overview of experiment and models of localized oscillations in granular systems, and mentions other systems with similar behaviors including the acoustics of stellar envelopes and the Swift-Hohenberg model (modified).

Author: Josh Guffin

Title: The Emergence of Spacetime in the IKKT model

Abstract: Ishibashi, Kawai, Kitazawa, and Tsuchiya (IKKT) have proposed a model describing type-IIB string theory on a flat background. Beginning with the Schild gauge-fixed form of the string action, they found that the matrix regularization of the action led to a zero dimensional matrix model equivalent to the complete dimensional reduction of ten dimensional super Yang Mills theory.  By examining an effective action of the matrix model around a diagonal background, an interpretation of the back ground as spacetime points emerges.

Author: Mitrabhanu Sahu

Title: Thermally activated phase slips and quantum phase slips in one-dimensional superconductors.

Abstract: We will briefly discuss the theories for thermally activated phase slips(TAPS) given by Langer, Ambegaokar, McCumber and Halperin(LAMH) and the theory of macroscopic quantum phase slips(QPS).Experimental evidence of thermally activated phase slips in superconducting nanowires (10-30 nm wide) and its agreement with LAMH theory will be discussed. We will then turn our attention to the question of quantum phase slips, by outlining various experimental data as well as different theoretical predictions surrounding the controversy whether QPS can be, or up to the present time, have been, observed experimentally.

Author: Lukas Urban

TItle: Metallic Phase in 2D Superconductors


Recent experiments in two dimensional thin films showed that a metallic state exists between the superconducting and insulating states.  In this paper I will review these experiments as well as some theories proposed to explain this state.

Author: Abhishek Roy

Title: Superflow in Solid Helium


The small mass and significant zero point motion of solid ${}^4$He make it very different from its conventional counterparts. In the seventies it was suggested that at very low temperatures solid helium might flow like a superfluid while remaining a crystal. This hidden ``supersolid'' phase was subsequently almost ruled out both by experiments and theoretical calculations. However, in 2004 Kim and Chan reported that when rotated at temperatures below 230mK a fraction of solid ${}^4$He does indeed refuse to be dragged around by its walls, a famous effect hitherto only seen in its superfluid partner. In this paper, I will describe the experiment, its consequences and possible theoretical explanation.

Title:  Emergent Gravity

Author: M. Yeh

In this paper, we will brief discuss how the effective metric emergent from condense matter models, how gracity emergent, and what is the physics analogues between condense matter model and our universe. Finally we brief discuss how space-time emergent in superstring Matrix model.