Seminars and Colloquia, January through June, 2013

• This Week's schedule.
• Earlier Semesters.
• Typical Week's schedule.
• January 1-4, 2013's schedule.
• January 7-11, 2013's schedule.
• January 14-18, 2013's schedule.
• January 21-25, 2013's schedule.
• January 28-February 1, 2013's schedule.
• February 4-8, 2013's schedule.
• February 11-15, 2013's schedule.
• February 18-22, 2013's schedule.
• February 25-March 1, 2013's schedule.
• March 4-8, 2013's schedule.
• March 11-15, 2013's schedule.
• March 18-22, 2013's schedule.
• March 25-29, 2013's schedule.
• April 1-5, 2013's schedule.
• April 8-12, 2013's schedule.
• April 15-19, 2013's schedule.
• April 22-26, 2013's schedule.
• April 29-May 3, 2013's schedule.
• May 6-10, 2013's schedule.
• May 13-17, 2013's schedule.
• May 20-24, 2013's schedule.
• May 27-31, 2013's schedule.
• June 3-7, 2013's schedule.
• June 10-14, 2013's schedule.
• June 17-21, 2013's schedule.
• June 24-28, 2013's schedule.

Seminars and Colloquia, Typical Week:

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Journal Club on Statistical Mechanics and Condensed Matter Physics, and Optics (Informal):

Oklahoma State Physics Department

Seminars and Colloquia, January 1-4, 2013

No talks scheduled: Prelim Exams

Oklahoma State Physics Department

Seminars and Colloquia, January 7-11, 2013

First Week of Classes

Oklahoma State Physics Department

Seminars and Colloquia, January 14-18, 2013

Second Week of Classes

Physics Colloquium:

Abstract:

Currently, the true potential of proton radiotherapy cannot be fully exploited due to uncertainties in the in-vivo range of the treatment beams caused by patient setup errors, day-to-day changes in patient anatomy, and limitations in our knowledge of the response of tissues to proton therapy. Current treatment techniques include the use of larger than desirable “treatment/safety margins” to account for these uncertainties and ensure proper dose delivery. These large margins increase the dose to surrounding healthy tissues, which severely limits the dose that can be delivered to the tumor, thus limiting proton therapy’s curative potential.

However, if the in-vivo range of the beam could be verified during treatment delivery, the current level of uncertainty in treatment delivery would be reduced. This would allow for a significant reduction in the treatment/safety margins, allowing the true potential of proton radiotherapy to be better exploited.

Fortunately, inherent to proton therapy is the emission of elemental ‘prompt’ gamma rays (PG) due to non-elastic proton-nucleus interactions in irradiated tissues. Each element in tissue emits a unique spectrum of PG energies along the path of the beam in the patient, making it a prime signal for beam range verification. To use PG emission for verification, however, it must be effectively measured and imaged. Due to the high energies of emitted PGs (up to 10 MeV), current gamma detectors cannot efficiently measure the energy and spatial information necessary to reconstruct PG images for proton beam range verification.

This seminar will provide an overview of the range uncertainty problem with proton radiotherapy, and discuss current research on methods to solve this problem. In particular, the development of methods for measuring and imaging PG emission during treatment delivery as a means of verifying proton beam range will be presented.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, January 21-25, 2013

Monday, January 21, 2013: Martin Luther King Day

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Abstract:

The Standard Model of particle physics has been tested experimentally to a high degree of accuracy. Despite its successes in describing particle interactions at very short distances, it has many glaring deficiencies. Among these are the many free parameters that parametrize fermion masses and mixings. The origin of fermion mass hierarchy and mixing still remains one of the great mysteries in particle physics. Even though the fermion masses are generated by the Higgs mechanism, the Higgs mechanism by itself does not explain the observed mass hierarchy and mixing patterns. The discovery of non-zero neutrino masses leads to yet another puzzle: why the neutrino masses are so small when compared to other fermions, and why two of the three neutrino mixing angles are so large when compared with their quark counterpart.

In this talk, I will discuss how these outstanding questions can be addressed in a supersymmetric grand unified model combined with a finite group family symmetry. In particular, I will describe a model which gives rise to realistic masses and mixing angles of all observed fermions, including the neutrinos, with a significantly reduced number of parameters. In this model, CP violation is entirely geometrical in origin. This leads to interesting implications for the generation of the matter-antimatter asymmetry in the Universe.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Journal Club on Statistical Mechanics, Condensed Matter Physics, and Optics (Informal):

Abstract:

Magneto-optical effects are often used as a tool to probe magnetization of a sample under study. For out-of-plane magnetization, it can be the polar Kerr effect odd in magnetization while for in-plane magnetization, quadratic magneto-optical Kerr effect (QMOKE) will serve the purpose provided it is strong enough at the frequency of used laser. However, much more interesting information pertaining to the electronic structure of the system is contained in the spectral dependence of these effects. Investigation of magnetic linear dichroism and birefringence of (Ga,Mn)As allows to identify transitions between individual electronic bands and their changes with Mn doping. On the experimental side, QMOKE measured in the spectral range ~0.1 to 2.5 eV turns out to display much sharper features than for instance infrared absorption. On the other hand, mean field k·p calculations allow to compare these to the underlying magnetic linear dichroism and birefringence.

Oklahoma State Physics Department

Seminars and Colloquia, January 28-February 1, 2013

Physics Colloquium:

Abstract:

Volumetric Modulated Arc Therapy (VMAT) is new generation arc therapy technique that shortens delivery time and reduces scatter dose to patients. VMAT is supported by both Elekta and Varian machines. However, due to the machine limit from each vendor, treatment plans of VMAT for various cancer sites need to investigate to be optimized for each machine. In this talk, we will present the VMAT technique for treating whole brain with hippocampus avoidance. We also explored Stereotactic Body Radiation Therapy (SBRT) for spinal cord by using VMAT to compare with other techniques such as IMRT and HybridArc.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Physics Colloquium:

Abstract:

Nanoscale particles have become promising materials in various biomedical applications, however, in order to stimulate and facilitate these applications, there is an urgent need for the understanding of their nanotoxicity and other related risks to human health. In this talk, I will discuss some of our recent molecular modeling work on nanotoxicity with IBM Blue Gene supercomputer. We show that carbon-based nanoparticles (carbon nanotubes, graphene nanosheets, and fullerenes) can interact and disrupt the structures and functions of many important proteins. The hydrophobic interactions between the carbon nanotubes and hydrophobic residues, particularly aromatic residues through the so-called p-p stacking interactions, are found to play key roles. In addition, metallofullerenol Gd@C82(OH)22 is found to inhibit tumor growth and metastases (i.e. toxic to tumor cells) with both experimental and theoretical approaches. These findings might provide a better understanding of “nanotoxicity” at the molecular level and help design better therapies with nanomedicine.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, February 4-8, 2013

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Abstract:

Since the 1970’s, people have developed a variety of ingenious ways to use the sun to power a home. While this has been successful in some regions, it has not been very effective in hot and humid climates. Recent advances in solar photovoltaic technology have made a solar-powered home practical and affordable in almost any climate. One can now live in a wonderful house, and also drive an electric car, powered entirely by the sun.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, February 11-15, 2013

Oklahoma AMO Physics Research Day:

Rescheduled to Friday, March 15.

Oklahoma State Physics Department

Seminars and Colloquia, February 18-22, 2013

Physics Colloquium:

Abstract:

Fundamental materials research is essential to move present-day energy storage technologies to the scale needed to develop all-electric vehicles and to manage intermittent sources such as wind and solar. Comparable advances are also required to develop compact power sources for new medical and military/aerospace applications. Structural studies of materials utilized in lithium battery and fuel cell technology are often hampered by the lack of long-range order found only in well-defined crystalline phases. Powder x-ray diffraction yields only structural parameters that have been averaged over hundreds of lattice sites, and is unable to provide structural information about amorphous compounds. Our laboratory utilizes solid state nuclear magnetic resonance (NMR) methods to investigate structural and chemical aspects of lithium ion cathodes, anodes, electrolytes, interfaces and interphases. NMR is element- (nuclear-) specific and sensitive to small variations in the immediate environment of the ions being probed, for example Li⁺, and in most cases, is a reliably quantitative spectroscopy in that the integrated intensity of a particular spectral component is directly proportional to the number of nuclei in the corresponding material phase. NMR is also a powerful tool for probing ionic and molecular motion in lithium battery electrolytes and polymer electrolyte membranes (PEMs) for fuel cells with a dynamic range spanning some ten orders of magnitude through spin-lattice relaxation and self-diffusion measurements. A survey of brief summaries of several recent NMR investigations will be presented: (i) water and proton transport in nanocomposite PEM fuel cells membranes; (ii) single crystal studies of LiMPO₄ (M = Fe, Co, Ni) lithium ion battery cathodes; (iii) electrode passivation in lithium ion batteries; (iv) structural aspects of CF_x primary lithium battery cathodes.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, February 25-March 1, 2013

Physics Colloquium:

Abstract:

Enveloped viruses infect cells by joining their membrane with that of the target host cell. This process is catalyzed by a viral fusion protein and in particular by the ~20-residue N-terminal fusion peptide (FP) region which binds to the host cell membrane. Solid-state NMR (SSNMR) has been used to determine high-resolution structures of the HIV and influenza virus FPs in membranes. SSNMR has also been used to measure distances between nuclei in the FP and nuclei in the lipid molecules in the membrane and it has been observed that there is a strong correlation between fusogenicity and depth of FP membrane insertion. Finally, SSNMR was used to quantitatively determine the population distribution of beta sheet registries for the membrane-associated HIV FP. There was a broad distribution of antiparallel registries and a good correlation between individual registry populations and their free energies of membrane insertion. A very different registry distribution was detected for the non-functional V2E mutant which binds to membranes but is not membrane-inserted.

There has also been significant progress in SSNMR of large domains of the membrane-associated influenza and HIV fusion proteins that contain FPs. In one approach, the FP was chemically synthesized, the large C-terminal region of the fusion protein was produced recombinantly in bacteria, and the large FP-containing protein was produced by native chemical ligation. Initial chemical synthesis of the FP allows for controlled isotopic labeling. In a second approach, most of the fusion protein including FP was produced recombinantly in bacteria. Purified protein yields from the bacterial lysates were initially unacceptably low and it was unclear whether the recombinant protein wasn’t being produced in the bacteria or whether solubilization and/or purification was ineffective. SSNMR was carried out on the insoluble fraction of the cell lysate and it was shown that >100 mg recombinant protein was being produced per L of culture. Most protein was in inclusion bodies and subsequent effort was therefore put into increasing solubilization of inclusion body protein. Similar results were obtained for several other proteins produced recombinantly in bacteria and point to solubilization rather than expression as the major problem in recombinant protein purified yield. The SSNMR method for detecting quantity of recombinant protein in inclusion bodies is general and straightforward and sample preparation is rapid and inexpensive. One other interesting SSNMR result is strong evidence for predominantly folded protein in inclusion bodies.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, March 4-8, 2013

Physics Colloquium:

Abstract:

The ATLAS and CMS experiments have caught what appears to be the elusive Higgs boson.  But is it really the final piece to the puzzle or a doorway to something new?  In the standard model, the Higgs mechanism has the amazing feature of explaining not only how electroweak symmetry is broken, but also how fermions acquire mass.  The experiments at CERN observed a particle decaying to photons or Z bosons, but if this is really “the” Higgs boson we must confirm that it couples directly to fermions.  I will present the most recent Higgs result from the Fermilab Tevatron collider.  The focus will be on the Tevatron’s strength in the important H→bb channel, which is currently the only evidence for direct Higgs-fermion coupling.  The hunt is over, but now it must be tamed.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Abstract:

With millions of top quarks produced at the LHC, particle physics is entering a golden era of top-quarks studies. Particularly interesting is the potential for top quarks to shed light on new physics models, and through associated production, play an important role in understanding the newly discovered Higgs boson sector. I will discuss well-motivated searches for new physics with top quarks and initial results and prospects for understanding the top quark-Higgs boson interaction, both in the short-term and over the next decade.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, March 11-15, 2013

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Abstract:

Elementary particles and their interactions have been successfully described by the Standard Model of particle physics with astonishing accuracy. Its predictions have withstood the challenge of every experiment for several decades. However the internal consistency of the theory as well as its explanation for the origin of the mass of fundamental particles relies on the existence of a massive scalar boson, the Higgs boson, that has eluded experimental searches for almost 50 years since its prediction in 1964.

In this colloquium a review of the importance of the Higgs boson within the Standard Model will be outlined along with a brief history of searches for its existence. These searches culminated with the independent discovery of a new boson with properties consistent with the long-sought Higgs boson by the ATLAS and CMS experiments at the Large Hadron Collider in July 2012. The updated results from the ATLAS experiment about this new particle and the implications of this discovery will be presented. Finally, prospects for future measurements to elucidate its identity will be discussed in light of the re-start of data taking with a more powerful accelerator and upgraded detector in 2015.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma AMO Physics Research Day:

Schedule:

Abstract:

In our laboratory we are using precise molecular spectroscopy to look for discrete symmetry breaking associated with fundamental particles. In particular we are searching for the Electric Dipole Moment of the electron (e-EDM). The possibility of the electron having some asymmetry in its charge distribution with a resulting EDM breaks time reversal symmetry. The e-EDM has a long history. It was first proposed by Ramsey and Purcell in 1950 and it has been a subject of successively more precise searches since then. Most high-energy particle theories predict a tiny but finite value for the e-EDM. We have chosen to pursue this search using the free radical PbF. I will discuss the properties of PbF which are advantageous for this search, our progress in understanding this molecule to high precision, ~100 Hz in the ground state, and our plans to carry out a molecular-beam experiment to search for the e-EDM.

Abstract:

Our immediate goals are to measure the complete vibrational spectrum of singly-excited molecular electronic potential curves of Rubidium using Feshbach optimized photoassociation (FOPA). While traditional spectroscopy identifies the lowest vibrational molecular states and photoassociation of ultracold atoms has proven very powerful in determining the highest-lying vibrational levels, often there is a substantial gap between these two regions limiting our knowledge of these important molecular interactions. Feshbach resonances have been used to enhance photoassociation signal by altering the initial wave function, increasing the overlap with the excited state wavefunction in this intermediate region. We are currently exploring the purely triplet 0_g⁻ state connected with the 2S_1/2+2P_1/2 separated atom limit of 85Rb. Our initial calculations of PA rates found from closed-coupled scattering calculations indicate that FOPA should be able to completely determine the vibrational spectrum of the 0_g⁻ state.

Abstract:

The throughput of a single fiber-coupled whispering-gallery microresonator, such as a fused- silica microsphere, can exhibit behavior analogous to electromagnetically induced transparency and absorption (EIT, EIA). These effects enable slow and fast light, respectively, in the form of pulse delay or advancement. Two different methods are used here to realize this behavior; in both methods, the key feature is the use of two coresonant orthogonally polarized whispering-gallery modes of very different quality factor (Q). The first method relies on intracavity cross-polarization coupling when a single mode is driven, and the second on a simple superposition of orthogonal throughputs when the two (uncoupled) modes are simultaneously driven. Using the second method produces a pulse delay approximately equal to the pulse width. This surprising result indicates that it is not mode coupling that is responsible for slow light, but rather simple mode superposition.

Abstract:

Abstract:

Rydberg atom physics is experiencing a renaissance because the long range interactions that occur between Rydberg atoms can be used to entangle them. With ultracold atomic samples and coherent spectroscopy, Rydberg atoms are a promising element for developing entanglement based devices such as quantum gates and single photon sources. We will give an overview of our efforts in this field to quantitatively understand Rydberg atom interactions, explore exotic states of matter, use Rydberg atoms as standards, and create useful quantum hybrid systems.

Abstract:

The resources required for an exact solution of the quantum N-body problem are widely believed to scale exponentially with N, typically doubling for every particle added. With current numerical resources, this problem hits an “exponential wall” around N=10 (within a factor of 2). Even the advent of quantum computers is not expected to solve this problem, since recent studies have predicted that exact solutions of N-body wave functions for fermions or bosons are unlikely to have efficient algorithms on quantum computers. This exponential wall has prompted the creation of many approximate methods to avoid this exponential scaling. In this talk, I will present a method which performs an exact rearrangement of this exponential wall using analytic building blocks with N as a parameter, i.e. the method now scales as N₀, shifting the exponential complexity to the order in the perturbation theory. Group theory and graphical techniques do the “heavy lifting” to allow a direct transformation from microscopic two-body interactions to macroscopic motions of large-N systems. This approach thus allows the study of arbitrarily large systems of identical particles through low order in our perturbation series.

Abstract:

We will present a novel time-dependent hyperspherical coordinate method for studying the dynamics of triatomic systems. The use of wave packets provides information over a distribution of scattering energies and one can also visualize the wave packet as it enters the interaction region and then returns to the asymptotic region where it is analyzed. This ability to visualize the wave packet as it propagates in time offers an intuitive, physically meaningful picture of the dynamics. Our results for H + H₂ and F + H₂ show that this method is more accurate over a wide energy range than other time-dependent methods.

Using adiabatically adjusting, principal axes hypersperical (APH) coordinates increases the computational efficiency, since the triatomic PES becomes symmetric, reducing the amount of coordinate space required to represent the evolving wave packet. Rearrangement processes are important in the areas of combustion chemistry, atmospheric chemistry, three-body recombination, collision induced dissociation, photo-dissociation and photo-association.

Abstract:

We experimentally investigated several aspects of an off-resonant atomic ratchet by exposing a Bose–Einstein condensate to short spatially- and temporally-periodic trains of pulses. We measured the mean momentum as a function of a scaling variable which is associated with an effective Planck constant as well as pulse parameters characterizing the kicking strength and kicking number. The experimental results show how the crossover between the classical and quantum dynamical behavior of the ratchet can be described using the scaling variable and that the ratchet momentum is determined by a universal scaling law. We also verified a current inversion predicted by theory.

Abstract:

The field of quantum information holds the promise of harnessing quantum resources to provide secure communications, perform complex calculations, and enhance the sensitivity of measurements. Among those resources, one of the most important is entanglement, which is characterized by correlations stronger than allowed classically. Due to its fundamental role in quantum information science, the generation and control of entangled states of light are active research areas. In this talk I will show that non-degenerate four-wave mixing (4WM) in rubidium vapor has applications in both of these areas. The use of this process makes it possible to generate highly entangled beams of light know as twin beams with some distinct properties. First, the generate quantum states contain multiple spatial modes, which leads to spatial quantum correlations. Second, the entangled twin beams are close to an atomic resonance, which makes it possible to obtain an efficient interaction with an atomic system. I will finish by giving an overview of future research directions.

Abstract:

The HBT intensity interferometer was invented by astronomers Hanbury Brown and Twiss, which gives a much more accurate measurement of angular size of distant stars. Unlike the Michelson stellar interferometer, the HBT interferometer measures the second-order intensity-intensity correlation of thermal light with two independent photodetectors at different places. The joint-photodection gives the intensity correlation ‹ I(x₁)I (x₂) ›, with the visibility (defined by the maximum and minimum of the measures as (max−min) / (max+min) up to maximum 33%.

The HBT intensity interferometer is now greatly improved by a new method discovered by Shih’s experimental group. They define the intensity I_> (I_<) as the intensity greater (smaller) than the average intensity I. In their experimental setting, a novel coincidence circuit is introduced, so that instead of directly measuring ‹ I(x₁)I (x₂) ›, they can now measure the four correlations: G_>> = ‹ I_>(x₁) I_>(x₂) › and G_> <, G_< >, G_<<. The measurements can give the intensity-intensity correlation G_>> with visibility more than 50%, as well as the anti-correlations G_> < and G_< > with 100% visibility.

We have developed a theoretical method to calculate the correlations G_>>, etc. In quantum optics, the light fields at two photodetectors can be denoted by the two field operators a(x₁) and b(x₂). The average intensity is then given by I = ‹ a⁺a › = ‹ b⁺b ›. We define the correlation functions G_>>, G_> <, G_{< >} and G_<< via relations like G_> < = ‹ :a⁺ab⁺b  θ(a⁺a−I )θ(I−b⁺b):  ›, here the step function θ(a⁺a−I ) means we only need the field with the instantaneous intensity a⁺a greater than I, and here : : denotes normal ordering of operators. These correlations are quantum and need to be calculated using the P-representation of quantum optics. We will present theoretical calculation of all the four correlations and show their comparison with experiments of Shih et al.

Abstract:

In this talk I will overview quantum phases of bosons, with emphasis on dipolar bosons, confined within single-, bi-, and multi-layer geometries. The results presented are based on Quantum Monte Carlo simulations based on the Worm algorithm and its extension, developed to deal with multi-layers/multi-components systems. I will discuss phases and phase transitions displayed by such systems — with emphasis on solids and supersolids —, and the experimental conditions required to observe such phases.

Abstract:

An atomic Bose–Einstein condensate (BEC) is a state where all atoms have a single collective wavefunction for their spatial degrees of freedom. The key benefit of spinor BECs is the additional spin degree of freedom. Together with Feshbach resonances and optical lattices, spinor BECs constitute a fascinating collective quantum system offering an unprecedented degree of control over such parameters as spin, density, temperature, and the dimensionality of the system. Spin-squeezing and entanglement are predicted to arise naturally in spinor BECs from either spin-exchange collisions or elastic collisions controlled by spin-dependent potentials. In addition, collective coupling of spinor BECs to a light field introduced by a quantum non-demolition measurement can also create spin-squeezed states. In this talk, we present the design and construction of a novel apparatus to generate spin-squeezing with sodium spinor BECs in optical lattices. We will also discuss spinor BEC’s immediate applications in quantum metrology, including magnetometry and atomic clocks.

Oklahoma State Physics Department

Seminars and Colloquia, March 18-22, 2013

Spring Break & APS March Meeting

Oklahoma State Physics Department

Seminars and Colloquia, March 25-29, 2013

Physics Colloquium:

Postponed until next semester.

Journal Club on Statistical Mechanics, Condensed Matter Physics, and Optics (Informal):

Abstract:

The specific heats of alternating layered planar Ising models with strips of width m₁ lattice spacing and “strong” couplings J₁ sandwiched by strips of width m₂ and “weak” coupling J₂ have been studied to investigate the effects of connectivity and proximity. We find that the enhancement in the specific heat of the strong layers due to the collective effects reflect the observations of Gasparini and coworkers in experiments on superfluid helium. In addition, we demonstrate that finite-size scaling holds in the different temperature regions after suitable rescaling and appropriate subtractions. (Work done in collaboration with Prof. M.E. Fisher.)

Oklahoma State Physics Department

Seminars and Colloquia, April 1-5, 2013

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, April 8-12, 2013

Physics Colloquium:

Abstract:

A sample lecture on the laws of thermodynamics will be presented as would be taught in introductory physics.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Physics Colloquium:

Postponed, as Dr. Austin’s flight has been cancelled.

Oklahoma State Physics Department

Seminars and Colloquia, April 15-19, 2013

Physics Colloquium:

Abstract:

Since the development of classical optical coherence theory in the mid 1990s, the random nature of light has been described by a hierarchy of coherence functions, which represent the statistical correlations of the electromagnetic field components in time and space, along with measures of coherence for each of degree of freedom (DoF), e.g., the degree of temporal or spatial coherence, the degree of polarization, and the Stokes parameters. No such measures exist for fields in multiple degrees of freedom (DoFs). For such fields, if one of two coupled DoFs is observed, with the other DoF ignored, this dimensional reduction may itself introduce additional uncertainty. No measures exist for delineating the uncertainty acquired by insensitivity to a DoF from the intrinsic uncertainty in the entire field, which is described by measures such as entropy. We posit that tools from quantum information science, which were developed extensively over the past few decades, provide measures for such delineation, and thus advance classical optical coherence.

We consider two binary DoFs: the polarization state of an optical beam in two spatial modes. When these DoFs are coupled, the state is analogous to the bipartite binary quantum state, e.g., the two-photon polarization state, which is described by two entangled qubits. We have demonstrated that Bell’s measure, which is commonly used in tests of quantum non-locality, may be used in the classical paradigm to delineate the intrinsic uncertainty from the entanglement-based uncertainty introduced when one DoF is observed with the other ignored. The measured degrees of partial coherence and partial polarization, together with the Bell measure are used to define new invariants describing the multi-DoF field. Bell inequality violation, which rules out a hidden variable theory in the quantum paradigm, indicates the impossibility of decomposing the beam as a sum of elementary beams each with uncoupled polarization and spatial DoF, in the classical paradigm.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3.00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, April 22-26, 2013

Prefinals Week

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, April 29-May 3, 2013

Finals Week

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, May 6-10, 2013

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, May 13-17, 2013

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Oklahoma State Physics Department

Seminars and Colloquia, May 20-24, 2013

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, May 27-31, 2013

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Oklahoma State Physics Department

Seminars and Colloquia, June 3-7, 2013

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, June 10-14, 2013

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, June 17-21, 2013

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, June 24-28, 2013

No talks scheduled.

Last Updated: May 24, 2013.

This page was prepared by Helen Au-Yang and Jacques H.H. Perk.