Spring 2015

January 23, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
Speaker: Dr. Bharat Ratra, Kansas State University
Host: Prof. Irina Novikova
Title: Dark Energy: constant or time variable? (... and other open questions)

Abstract: Experiments and observations over the last decade have persuaded cosmologists that (as yet undetected) dark energy is by far the main component of the energy budget of the universe. I review a few simple dark energy models and compare their predictions to observational data, to derive dark energy model-parameter constraints and to test consistency of different data sets. I conclude with a list of open cosmological questions.


January 30, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
Speaker: Prof. Christine Aidala, University of Michigan
Host: Prof. W. Deconinck
Title: Spin-Momentum Correlations, Aharonov-Bohm, and Color Entanglement in Quantum Chromodynamics
Abstract: After the development of QCD in the last quarter of the 20th century, we are now in the early years of an exciting new era in which much more quantitative QCD calculations can be tested against increasingly sophisticated experimental measurements.  Advances include a greater focus on the dynamics of quarks and gluons within bound states and in the process of bound-state formation.  Over the last decade and a half, studies initially focused on spin-momentum correlations in the proton have brought to the fore several deep, fundamental issues within QCD.  We are now exploring the physical consequences of gauge invariance in QCD as a quantum field theory, analogous to the Aharonov-Bohm effects familiar to many from QED but predicted for any gauge-invariant quantum field theory.  Given the unique non-Abelian nature of the QCD gauge group, these quantum mechanical phase effects lead to an exciting novel prediction of entanglement of quarks and gluons across QCD bound states.

February 6, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Dr. Alberto Marino, University of Oklahoma
Host: Prof. E. Mikhailov
Title: Controlling the Spatial Properties of Entangled Twin Beams
Abstract: I will present some recent work on the generation and control of highly entangled beams of light, known as twin beams.  The quantum correlations present in twin beams have recently generated great interest due to their applications in quantum information, quantum imaging, and quantum computing. In this talk I will show that non-degenerate four-wave mixing (FWM) in a rubidium vapor cell is an excellent source of continuous-variable (CV) entangled twin beams, with an intensity-difference noise of less than 13% of the corresponding classical shot-noise level.  Unlike other systems that rely on the use of a cavity, this system can support a large number of spatial modes. This leads to spatial quantum correlations and makes it possible to produce CV entangled images. I will describe some resent experiments in which we study the effect of the size and profile of the pump required for the FWM on the minimum size of the spatial correlations, or coherence area.


February 13, 2015  (Friday) 4:00-5:00p.m. Small Hall 110

Speaker:  Dr. Simona Malace, Jefferson Lab
Host: Prof. W. Deconinck
Title: The Structure of the Nucleon
Abstract: Over the past decades physicists have made dramatic progress in understanding matter in terms of its fundamental constituents and their interactions. We now think of nucleons as being made of quarks and gluons held together by the strong force. Tremendous experimental and theoretical efforts around the world lead to the emergence of a fairly viable model that describes the nucleon structure and its dynamics in terms of quark and gluon distribution functions (PDFs) and their evolution. Quantum Chromodynamics (QCD) became the theory of strong interactions. However, fully understanding the dynamical makeup of free nucleons remains still a challenge. In this talk I will emphasize ongoing theoretical and experimental efforts to extend the PDF-based description of the nucleon structure into the non-perturbative regime and to understand the phenomenon of quark-hadron duality which could become a powerful tool to probe confinement. I will also highlight plans for an upcoming experiment at Jefferson Laboratory set to answer in the most precise manner to date the fundamental question of whether the nucleon separated structure functions are modified differently by the nuclear medium. This experiment will also yield high-precision measurements for the extraction of nuclear patron distribution functions. 


February 20, 2015  (Friday) 4:00-5:00p.m. Small Hall 110
Speaker:  Dr. Alexander Balatsky "CANCELLED"
Host: Prof. E. Rossi
Title: Dirac Materials

Abstract: Recently a new single-layer material—graphene—has been discovered. This is a material where quasi-particle behavior is described by very same Dirac equation that governs behavior of relativistic particles. Dirac  fermionic spectrum leads to very unusual properties of these materials, including   Klein paradox, chirality of carriers, unusual electron transport and impurity states. These properties are not unique to graphene, instead they represent universal consequences of the Dirac spectrum of the fermionic excitation sector. I will explore these similarities with other materials exhibiting similar spectra including d-wave superconductors, superfluid 3He and recently discovered topological insulators and discuss the unique role of  symmetries that protect the Dirac spectrum. I will also discuss how we can use modern tools to design Dirac Materials and perform their quantum imaging. Iwill illustrate how the ripples in the Dirac sea produced by defects can induce fascinating features that can be probed locally.


March 6, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
Speaker: Prof. Mike Snow, University of Indiana
Host:  Prof. W. Deoconinck
Title: "Nuclear/Particle/Astrophysics with Slow Neutrons"
Abstract: Experiments with slow neutrons can address a number of interesting open questions in nuclear/particle/astrophysics. In this talk I will describe how slow neutrons are produced and manipulated and present a few examples of experiments in this field.  

March 27, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
Speaker: Dr. George Schwiete. University of Mainz, Germany
Host: Prof. E. Rossi
Title: TBA
Abstract: TBA

April 3, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
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April 10, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
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Host: Prof. A. Walker-Loud
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April 17, 2015 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: TBA
Host: Prof. A. Walker-Loud
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April 24, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
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May 1, 2015 (Friday) 4:00-5:00p.m. Small Hall 110
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