Session A1: Plenary I

Introduction

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Probing the existence of extra dimensions with gravitational-wave observations

At the turn of the last millennium, higher-dimensional braneworld physics presented a possible solution to the hierarchy problem. Here, I describe gravitational wave (GW) signals in braneworld models that have been studied thus far. These include black hole quasi-normal modes and the stochastic GW background. I also examine the challenges that the novel aspects of these signals present to gravitational-wave astronomers, and the new physics that they might unravel.   

Latest Results from the Tevatron

The Fermilab Tevatron is currently the highest energy particle collider in the world. The era known as ``Run II'' started in 2001 and has provided more than 10 times the dataset of ``Run I,'' which took place in the early 1990s. The CDF and D\O\ experiments are exploiting this data to measure a wide range of quantities in a quest to test the Standard Model of Particle Physics to greater precision or to directly search for sources of new physics. I will present the current status of data-taking at the Tevatron, including a discussion of the most recent physics results. Local interests will be highlighted, including studies of the top quark from the D\O\ experiment.   

The Search for Missing Baryons with Linearly Polarized Photons at Jefferson Lab

The set of experiments forming the g8 run took place in Hall B of Jefferson Lab during the summers of 2001 and 2005 These experiments made use of a beam of linearly-polarized photons produced through coherent bremsstrahlung and represent the first time such a probe has been employed at Jefferson Lab. The scientific purpose of g8 is to improve the understanding of the underlying symmetry of the quark degrees of freedom in the nucleon, the nature of the parity exchange between the incident photon and the target nucleon, and the mechanism of associated strangeness production in electromagnetic reactions. With the high-quality beam of the tagged and collimated linearly-polarized photons and the nearly complete angular coverage of the Hall-B spectrometer, we seek to extract the differential cross sections and attendant polarization observables for the photoproduction of vector mesons and kaons at photon energies ranging between 1.3 and 2.2 GeV. We achieved polarizations exceeding 90\% and collected over six billion events, which, after our data cuts and analysis, should give us well over 100 times the world's data set. I shall report on the experimental details of establishing the Coherent Bremsstrahlung Facility and present some preliminary results from our first run.   

Building Robust Qubits

In 1994, Peter Shor discovered that quantum computers could efficiently factor whole numbers, a task for which there is no known classical algorithm and whose difficulty is at the heart of modern public key cryptosystems. This amazing theoretical result, however, is mostly for naught if we cannot build a large scale quantum computer. In this talk I will discuss the difficulties in building a quantum computer and why we are confident that a large scale quantum computer can be built. In particular I will discuss the thershold theorem for fault- tolerant quantum computation and then describe recent work which seeks to implement the ideas of fault-tolerant quantum computation in many-body strongly interacting quantum systems. Such self-correcting quantum computers have the potential to jumpstart an age of quantum information devices.   

Lighting Up Molecular Players in Learning with Evanescent-Wave Microscopy

Unraveling the molecular processes that underlie learning remains one of the most intriguing, unresolved problems in science. Learning and memory formation are believed to reflect alterations in the connections among nerve cells. These alterations are driven in part by proteins that are secreted from the surface of nerve cells. The secreted proteins act locally to mediate changes in nerve cell connectivity. Molecular processes, such as protein secretion, that occur near the cell surface can be studied in living cells using a biophysical technique known as evanescent-wave microscopy. In this technique, proteins of interest such as the molecular players in learning are fluorescently labeled using genetic engineering, and then living cells containing the proteins are illuminated with evanescent excitation light. The evanescent excitation light decays exponentially in intensity with distance from the cell surface, causing fluorescently tagged proteins to ``light up'' as they move toward or are secreted from the cell surface. In addition, proteins become invisible as they move more than $\sim $300 nm away from the cell surface. In this talk, I will discuss both evanescent-wave microscopy and some recent insights that we have obtained using this technique into pivotal processes that underlie learning.   

Physics Education Research and its Impact on Classroom Instruction

In recent years systematic investigations into student learning of physics have been carried out at an increasing pace, particularly at the undergraduate level. This work, broadly known as ``physics education research,'' involves exploring the process by which students come to understand physics concepts, and uncovering the difficulties and obstacles encountered by students as they learn. The ultimate outcome of this work is the development of new and more effective instructional materials and pedagogical strategies. I will outline the principal goals and methods of this research and show how it can lead to improved learning in the classroom. I will illustrate the process by discussing an ongoing investigation into student learning of thermal physics.