Krishna Vemuru- SPACS Colloquium October 11, 2012, 3pm

Magnetic nanostructures

Johnson Center 325

Vemuru abstract: Synthesis and characterization of magnetic nanostructures is an important aspect of research in nanoscience.  In order to improve the characteristics of nanomaterials based devices, it is important to understand the structure property relation as well as the mechanism of the magnetic ordering. In this talk, I will introduce magnetic nanostructured materials with applications in high density magnetic data storage. Some of these are rodlike metallic iron and g-Fe2O3 nanoparticles,  PZT thin films with Co nanostructures,  FeRhPd/Co thin films, core-shell structured FePt, FePtCu, and FePtAu nanoparticles. I will present the details of the nanostructural characterization using small angle neutron scattering, and the element specific magnetic moment determination using x-ray magnetic circular dichroism spectroscopy.

Khan Mahmoud, Quantum over Brunch Friday, Sept. 21, 2012, 11am

Creating Schrodinger’s cat state with Bose-Einstein condensates in multiple wells
Khan Mahmoud, JQI

Planetary Hall, Room 306, 11am (+ lunch after noon)

Quantum superposition principle, when applied to macroscopic objects, gives rise to seeming paradoxes as highlighted by Schrodinger in his famous thought experiment involving dead-and-alive cats. Unlike superpositions of different spin states of an electron, a classical object such as a cat cannot be found in a superposition of two distinct states. I will present a proposal for creating such highly entangled states with ultracold atomic BEC in a multiple well setting. Motivated by the unstable equilibrium dynamics of a rigid pendulum, I will discuss how a BEC in a double well can be evolved into a superposition of hundreds of particles simultaneously in both wells. I then generalize this method to BEC in multiple wells showing the creation of multi-positional cat states. Possible applications of cat states include precision measurements, quantum information processing, testing quantum-classical boundary, etc.

Brandon Anderson, Quantum over Brunch Friday, Oct. 12, 2012, 11am

Science and Technology I, Room 306, 11am (+ lunch after noon)

Brandon Anderson, JQI
TBA

Phil Rubin, Quantum over Brunch Friday, Nov. 2, 2012, 11am

Science and Technology I, Room 306, 11am (+ lunch after noon)

Phil Rubin, GMU
TBA

James Murray, Quantum over Brunch Friday, Nov. 16, 2012, 11am

Science and Technology I, Room 306, 11am (+ lunch after noon)

James Murray, Johns Hopkins University
TBA

So Takei, Quantum over Brunch Friday, Nov. 30, 2012, 11am

Science and Technology I, Room 306, 11am (+ lunch after noon)

Superconducting proximity effect: from transport and fluctuations to topological superconductivity”
So Takei, University of Maryland

The study of hybrid structures involving superconducting and non-superconducting materials has recently enjoyed a renewed level of activity. On the one hand, focus is on the physics of superconductor-ferromagnet junctions due to the recent emergence of experiments showing intriguing and unexpected transport behavior through such structures. On another front, the most recent excitement in the field originates from the fact that a rather conventional example of these hybrid systems can harbor long-sought exotic emergent particles known as Majorana fermions. In line with these activities, I will present two connected topics. The first part is motivated by a recent experiment [1] that observed a highly unusual transport behavior of ferromagnetic Cobalt nanowires proximity-coupled to superconducting electrodes. I propose an explanation for both the anomalously-strong proximity effect and the mysterious resistance peak that preempts the superconducting transition in this experiment [2]. In the second part, I theoretically address the origin of the mysterious “soft gap” measured in the tunneling conductance of the proximity-induced superconductivity in a semiconductor-superconductor hybrid structure, where the observed zero-bias conductance peak [3] has created …

Victor Vakaryu, Quantum over Brunch Friday, Nov. 9, 2012, 11am

Science and Technology I, Room 306, 11am (+ lunch after noon)

Victor Vakaryuk, Johns Hopkins University
TBA

Fall 2012 Quantum Center Seminar Schedule

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Mahmoud Lababidi, GMU
Weyl superconductors: an introduction

SEPTEMBER14

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Khan Mahmoud, JQI
Creating Schrodinger’s cat state with Bose-Einstein condensates in multiple wells

Quantum superposition principle, when applied to macroscopic objects, gives rise to seeming paradoxes as highlighted by Schrodinger in his famous thought experiment involving dead-and-alive cats. Unlike superpositions of different spin states of an electron, a classical object such as a cat cannot be found in a superposition of two distinct states. I will present a proposal for creating such highly entangled states with ultracold atomic BEC in a multiple well setting. Motivated by the unstable equilibrium dynamics of a rigid pendulum, I will discuss how a BEC in a double well can be evolved into a superposition of hundreds of particles simultaneously in both wells. I then generalize this method to BEC in multiple wells showing the creation of multi-positional cat states. Possible applications of cat states include precision measurements, quantum information processing, testing quantum-classical boundary, etc.

SEPTEMBER21

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Brandon Anderson, JQI
TBA

OCTOBER12

Enrico Rossi, Quantum over Brunch Friday, Nov. 9, 2012, 11am

Science and Technology I, Room 306, 11am (+ lunch after noon)

Enrico Rossi, William and Mary
TBA