Monday, Dec 11 2006

The Nucleus Strikes Back

Can two protons or neutrons be "partners" within a nucleus unless they have agreed to be different? The answer is No, as discovered in a study by a American-Israeli team of experimentalists and theorists, including Mark Strikman of Penn State. They analyzed the data from an experiment performed at Brookhaven National Lab, led by Alan Carroll of BNL and Steve Heppelman of Penn State, in which a high-energy proton beam knocked protons out of carbon nuclei. As L. Frankfurt and M. Strikman predicted two decades ago, when the velocity of the ejected proton before the reaction is greater than 1/4 the speed of light, a fast neutron partner is always ejected in the opposite direction. Below this velocity, no such partner neutrons are observed. It is amazing that partner neutrons are observed with a probability close to one, with essentially no partner protons, since one would naively expect comparable numbers of proton and neutron partners coming from a carbon nucleus, which is a bound state of six protons and six neutrons. These results reveal a fundamental property of the strong interaction, relevant for the stability of nuclei. The consequences of this phenomenon for neutron stars, which are composed mainly of neutrons that are very close together, must be significant and are yet to be understood.

Sunday, Dec 3 2006

How Thin?

How thin can a ferroelectric be? This question lies at the root of determining how much data can be stored on a “smart card”—a memory chip that makes use of ferroelectric materials. To answer this question requires probing ferroelectricity in nanoscale systems, which is made possible by using ultraviolet Raman spectroscopy. In agreement with theory, we find that the ferroelectric BaTiO₃ in thin sandwiches with non-ferroelectric SrTiO₃ layers can be as thin as one monolayer (just 4 Angstroms thick) and still be ferroelectric. More...

Saturday, Dec 2 2006

Yunes wins “Blue Apple” award

The 16th Midwest Relativity Meeting was held in November at Washington University in Saint Louis, Missouri. The event also marked the 60th birthday of Clifford Wills, a former undergraduate advisor for Nicolas. With over 90 participants this year’s event boasts the largest attendance to date. The award called "Blue Apple", is presented in recognition of the best student presentation at the meeting. Nicolas’s talk entitled: "How to kick a hole and other eccentric stories" was based on a collaborative effort with Dr. Pablo Laguna and Dr. Carlos Sopuerta and has merited publication in the Astrophysical Journal.

Wednesday, Nov 22 2006

Emerging Explorer

Stephon Alexander, assistant professor of physics and of astronomy and astrophysics, has been named a 2006 National Geographic Emerging Explorer in recognition of his research exploring the secrets of the early universe, at the intersection of fundamental physics and cosmology. Alexander has research interests that include investigations at the interface between cosmology and such fundamental areas of physics as string theory -- which attempts to merge quantum mechanics with Albert Einstein's general theory of relativity as a description of fundamental physics-and quantum gravity -- which attempts to merge two theories that describe the four fundamental forces of nature into a unified "theory of everything." He also is working on ways to use gravitational waves to probe the connection between inflationary theory -- which describes the epoch in the universes' past when it rapidly expanded from a microscopic size to the size that people observe today -- and the origin of matter in the universe. Alexander's research also includes efforts to use quantum gravity in order to understanding the cosmological constant, also known as dark energy.

Friday, Nov 17 2006

AAAS & APS Fellows

Professors Moses Chan, Thomas Mallouk and Jorge Pullin have been elected as Fellows of the American Association for the Advancement of Science, and Professor Ying Liu has been elected a Fellow of the American Physical Society.

Thursday, Oct 5 2006

Co-op Student of the Year

Jack Flicker, a summer 2006 Penn State graduate with a B.S. in Physics (and Chemistry) from Harrisburg, has been selected as the recipient of the 2006 PennACE (The Pennsylvania Association of Colleges and Employers) JoAnne Day Co-op Student of the Year award. Jack completed two co-op assignments, one with the Walter Reed Army Institute of Research in Silver Spring, MD and the other at the Electro-Optics Center in State College, PA. At Walter Reed, he created a computer simulation of blood storage containers to be used by medics in extreme environments. His summer experience at the Applied Research Lab Electro Optics Center, his second co-op assignment, was to develop and carry out a small-scale experiment involving laser-powered solar cells for Navy submersibles. He designed, conducted and analyzed the results of an experiment to investigate the feasibility of remote charge of batteries of an underwater unmanned vehicle using a laser source irradiating solar cells. Jack presented his findings at the ArmTech Conference to local and national government, military and corporate leaders. Jack also frequently volunteered for the Co-op Office to speak to incoming freshmen at open houses or to current students in his major. He was the recipient of several scholarships and awards including the Lane B Granville Memorial Award, H.A. Bright Memorial Award, and the Elizabeth Smith Memorial Scholarship. He is currently enrolled in the Ph.D. program in Material Science at Georgia Tech. Information about the Penn State Eberly College of Science Cooperative Education Program is available on the web.

Wednesday, Oct 4 2006

The Economics of Loop Quantum Gravity

Professor Ashtekar's work on Loop Quantum Gravity is featured in the Economist's September 28, 2006 issue: "...Loop quantum gravity... was dreamed up in 1986 by Abhay Ashtekar, of Pennsylvania State University. He rewrote the equations of general relativity to make them compatible with quantum mechanics. It really took off as an alternative to string theory, though, when it was picked up by Lee Smolin, now of the Perimeter Institute in Waterloo, Ontario, and Carlo Rovelli, of the Universit de la Mediterrane in France. Together, they developed Dr Ashtekar's idea to show that it implies that space and time are not smooth, as general relativity requires, but come in tiny, distinct chunks..." More...

Sunday, Oct 1 2006

NOVA Features Penn State Space Scientists

Penn State scientists and engineers working with NASA's Swift space observatory were featured as part of a new NOVA program that debuted at 8:00 p.m. on Tuesday, 31 October 2006. The program documents how astrophysicists are closing in on the proof they have sought for years, that one of the most destructive objects in the universe-a supermassive black hole-is lurking at the center of our own galaxy. "Could it flare up and consume our entire galactic neighborhood?" is one of the questions explored during NOVA's mind-bending investigation into one of the most bizarre corners of cosmological science: black-hole research. The program reveals elusive secrets of supermassive black holes through stunning computer-generated imagery, including an extraordinary simulation of what it might look like to fall into the belly of such an all-devouring beast. A NOVA video crew visited Penn State to film scientists working at the control center for the Swift satellite, which is dedicated to studying the formation of black holes throughout the universe. Penn State controls Swift's science and flight operations for NASA from the Penn State Mission Operations Center, and Penn State led in the development and assembly of two of Swift's three telescopes. Swift is a unique, multifaceted satellite that is designed to observe gamma-ray bursts, the most powerful explosions known, which appear to be caused by the birth of distant black holes. More... (Image: Nova, PBS)

Sunday, Oct 1 2006

Faculty Position Available

The Department of Physics at The Pennsylvania State University invites applications for faculty appointments effective the Fall semester of 2007. Applicants should have a Ph.D. and an outstanding research record. Rank will be commensurate with qualifications and experience. We seek to recruit in the areas of AMO physics, condensed matter theory and cosmology of the early universe. However, exceptional candidates in any of the department's current areas of research will be considered. These areas are AMO physics, biological physics, condensed matter physics, gravitational physics, particle physics and particle astrophysics. Candidates at the junior level should submit a letter of application, a curriculum vitae, a brief description of research plans, and arrange for four letters of recommendation to be sent to: Jayanth Banavar, Box 262, Department of Physics, 104 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802. Nominations and applications for senior positions should be sent to the address above together with a list of at least six references. Applications completed by December 1, 2006 will be assured of consideration. However, applications will be considered until the positions are filled. Job application assistance is available for dual career situations. Penn State is committed to affirmative action, equal opportunity, and the diversity of its workforce.

Thursday, Sep 7 2006

Initial Conditions of the Universe

An old dream of science is to find an ultimate theory by which one can explain and in principle predict everything. Some branches of quantum gravity have, in the context of string theory, relived this idea in a modern form, but recent research revealed how far we really are from its realization: Looking for solutions which can describe a universe accelerating at late times, much too many of them turned up without, so far, a way to select one among them. Thus, while one may believe that certain theoretical constructions are unique, too many solutions result to be compared with observations. Some of these solutions may be close to what we see in our universe, but this will be only a small fraction of all possibilities. A newly proposed viewpoint by Hawking and Hertog, combining different properties of quantum gravity theories, claims to solve this problem. Based on quantum cosmology, conditions for unique solutions, appearing as quantum superpositions of classical alternatives, can be devised and used for predictions. However, the procedure raises more questions regarding whether physics is to just predict or to explain observed phenomena. These issues are discussed in Nature 442, 988. Nature News & Views, M. Bojowald.

Wednesday, Sep 6 2006

To the Swift

The Swift Gamma Ray Burst Explorer satellite detected in February of this year the longest-lasting burst so far, labelled GRB060218, more than 2000 seconds long. Such gamma ray bursts are known to result from stars more massive than 25 solar masses which undergo core collapse, resulting in a highly relativistic jet which produces the gamma-rays, and at the same time the star ejects its outer envelope in a supernova explosion. While the gamma-rays from jets have been extensively studied, this is the first time that the supernova explosion has been observed as it breaks out from the opaque stellar wind of the progenitor star. Swift's sensitive X-ray detectors observed a characteristic black-body emission, which starts out weak compared to the non-thermal gamma/X spectrum of the jet burst, and becomes dominant by the time the jet burst ends, indicating the break-out of the supernova shock wave. Members of the Swift Penn State team published these results in a recent issue of Nature (vol. 442, p. 1008, August 31, 2006).

Tuesday, Aug 22 2006

Nanoparticles and Mysterious Galactic Lights

Professor Will Castleman, in collaboration with researchers Ashraf Ali at Goddard and Shiv N. Khanna at Virginia Commonwealth University, has synthesized silicon oxide nanoparticles that may shed light on the first steps in the formation of planets and the origins of mysterious blue and red light emission, known as the Extended Red Emission and Blue Luminescence, in our galaxy. More... (Image: A. Reber, VCU)

Tuesday, Aug 15 2006

Recoil in a Beam

Unlike water, which speeds up as it passes through a small nozzle, photons of light have less momentum at the focus of a laser beam. A pencil-like laser beam can be made by intersecting two infinitely wide light waves at a small angle. Kurt Gibble of Penn State explains, "You might think that an atom would absorb a photon randomly from only one of the beams," “but instead, the atom recoils with a speed that is less than it would get from the momentum of either of the infinitely wide photons, with no sideways recoil.” Kurt Gibble’s theoretical paper studies the momentum of an atom after absorbing a photon and how it affects atomic clocks and precise measurements with atom interferometers. This work was featured recently in Physical Review Focus. More...

Tuesday, Jul 25 2006

The Hot & Cold of Packing

The mechanics of packing grains, such as wheat in a silo or sand in a jar has been an intriguing question to scientists as well as to engineers. Until now it has been assumed that the packing fraction - the fraction of sample volume that is filled by grains rather than empty space - of granular material is mostly determined by the mechanical process the pile experienced such as pouring or tapping. Recently the group of Peter Schiffer found that by simply raising and then lowering the temperature of grains in a container one can controllably change the way grains pack. Schiffer and co-workers conclude that the packing fraction increases when heating of the grains is followed by cooling – known as thermal cycling – and the packing fraction continues to increase with multiple thermal cycles. More...

Saturday, Jul 22 2006

Presidential Early Career Award

Kenneth M. O'Hara has been recognized as one of the most promising young scientists and engineers in the United States by being awarded the Presidential Early Career Award for Scientists and Engineers at the White House. The award is the nation's highest honor for professionals at the outset of their independent research careers. O'Hara is one of 56 researchers to receive the award this year. O'Hara received the award in recognition of his research in the area of ultra-cold atomic gases, which is expected to increase the understanding of many-particle quantum systems and to lead to the development of novel quantum-mechanical devices. He was honored, as well, for his mentoring of graduate and undergraduate students, including those from groups underrepresented in the sciences. As part of his research, O'Hara studies ultra-cold atoms confined in a lattice formed from laser beams. This "optical lattice" mimics the potential that electrons experience when they move around a crystalline lattice in solid-state matter. Atoms in the lattice exhibit many of the same phenomena observed in solid-state electronic devices. "What makes studying these phenomena in an atomic system so exciting is that many experimental parameters are widely adjustable," O'Hara explained. "For example, we can modify the density of the atoms, the geometry of the lattice, the degree of disorder in the lattice and even the interaction strength between the atoms. These modifications allow us to engineer idealized model systems in which to study quantum many-body phenomena such as magnetism, superconductivity and quantum phase transitions." He added, "We also expect to have the ability to engineer systems that have no analog in solid-state physics, which could lead to the discovery of entirely new states of matter and the development of new devices."

Wednesday, Jul 12 2006

Batteson is Student Marshall

Mr. Bruce Batteson, a Physics major with a Math minor, has been selected as the Eberly College of Science Student Marshall for the summer 2006 graduation ceremony to be held on August 12th. This honor, typically given to the ECoS graduating senior with the highest cumulative GPA, means that he'll be representing all of the graduating students in ECoS this summer. Mr. Batteson was able to complete his undergraduate degree in just over three years (including this Summer 2006) which is a remarkable feat! The Physics Department is happy to congratulate him on his achievement and to wish him (and all of our seniors graduating at the Summer 2006 ceremony) the very best with their future careers.

Saturday, Jul 1 2006

Engle wins NSF International Research Fellowship

Jonathan Engle is graduate student in the physics department of Penn State, studying under Professor Abhay Ashtekar. In March, he won an NSF International Research Fellowship to work with Carlo Rovelli's research group at the Centre de Physique Theorique in Marseille, working in fundamental areas of loop quantum gravity. Loop quantum gravity is an approach to formulating a quantum theory of gravity that preserves the primary insight of Einstein that gravity and geometry are aspects of the same physical reality. Of over 200 proposals submitted from all areas of science, Jonathan's placed second. This will be his first postdoctoral appointment, to start in September. When he is not doing physics, Jonathan enjoys basketball, playing the violin, Gregorian chant and reading books on Catholic spirituality.

Saturday, Jul 1 2006

McConville Wins Vanderbilt Prize

William (Bill) McConville, an upcoming senior Physics major, has been named a finalist for the Vanderbilt Prize for Undergraduate Research. The Vanderbilt Prize is an annual award which recognizes original research conducted by undergraduate students in the areas of physics and astronomy. Bill was chosen as a finalist for his contributions to research involving the study of geometrical magnetic frustration within arrays of lithographically fabricted ferromagnetic islands of nanoscale size. Bill was a co-author (along with Profs. Samarth, Schiffer, and Crespi, and several Physics graduate students) on an article describing their research which appeared on the cover of the Jan. 19th issue of Nature. Finalists for the Vanderbilt Prize receive a cash prize, as well as an invitation to attend a banquet held at the University. More information about the award is given at the web site http://vuprize.physics.vanderbilt.edu which will be updated with information about the 2006 award in the future. Bill is a member of the Schreyer Honors College and comes from Glen Mills, PA and has been working in Prof. Schiffer's labs since his first summer.

Wednesday, Jun 21 2006

Services for Karin Oldberg Shaw

Our retired colleague Peter Shaw lost his wife earlier this week. Karin Oldberg Shaw died Monday, June 19th 2006 at Hershey Medical Center. Calling hours, 2-4 and 7-8:30PM, wake service 8:30 -9:00PM, Friday, June 23, 2006 at Good Shepherd Catholic Church, Gray's Woods Boulevard, Patton Township. Funeral, 10:30AM, Saturday June 24th, 2006 at the church with the Rev.Philip Bender officiating. Memorials to Pennsylvania Center Orchestra, 119 S. Fraser Suite D State College, PA 16801; or CentrePeace Capital Campaign, 3013 Benner Pike, Bellefonte, PA 16823.

Friday, Jun 16 2006

Welcome Baby Martell

Emily and Scott Martell announce the birth of their second child, Samuel Fitzpatrick Martell. He is 8 pounds 4 ounces and 22 inches long. Mother and baby are both doing well.

Thursday, Apr 27 2006

Before the Big Bang

Einstein's general relativity predicts that space-time ends at the Big-Bang and physics simply stops. However, general relativity is incomplete because it ignores quantum physics. A recent Physical Review Letter by A. Ashtekar, T. Pawlowski and P. Singh shows that quantum gravity effects change the situation dramatically by making gravity repulsive near the Big Bang. The universe bounces back, producing a large pre-Big-Bang branch. Quantum physics does not stop but remains predictive. Because these authors do not presuppose a continuum space, unlike in other investigations of the Big Bang, calculations continue to be valid even when the fabric of space tears. The pre-Big-Bang branch of the universe is joined to the post-Big-Bang branch unambiguously by a `quantum bridge'. These results are obtained using a standard cosmological model and mathematically rigorous methods of `loop quantum gravity', a leading approach to the problem of unifying general relativity and quantum physics. (Physorg) More... (Image: Cliff Pickover, www.pickover.com)

Friday, Apr 14 2006

Quantum Newton's Cradle

The quantum Newton's cradle is a modern version of the well known lecture demo and desk toy with five steel balls suspended in a line from strings. It starts with an array of thousands of trapped 1D Bose gases, each consisting of about 100 atoms. Each atom is put in a quantum superposition of going to the right and to the left, so that they oscillate pendulum-like in their trap. Experimenters in David Weiss' labs at Penn State have shown that even after each atom bounces off other atoms ten thousand times, they all still oscillate with their original amplitude. The process of thermal equilibration is completely shut off in 1D gases. The quantum Newton's cradle is the first experiment to study a many-body integrable system out of equlibrium. It has potential implications to future designs of atom interferometers and force sensors. By letting some non-integrability creep into the experiment, similar experiments will allow the onset of chaos in many-body systems to be studied in a very well-controlled way.

Thursday, Apr 13 2006

Qihua Xiong wins NanoMaterials Award

Mr. Qihua Xiong, a graduate student in Prof. Peter Eklund's Research Group working in the area of NanoMaterials Physics has received the Graduate Academic Excellence Award for 2006 from the Inter-College Materials Science and Engineering Graduate Program. Highlights of Mr. Xiong's research include: the observation and characterization of Surface Optic phonons in semiconducting nanowires, which he connected to the periodic diameter modulation in his nanowires; the first observation of "automatic" twinning superlattice formation in III-V semiconducting nanowires; the first observation of strongly polarized Raman scattering from GaP nanowires, which is connected to the shape-directed redistribution of electromagnetic fields inside the nanowires; and pioneering development of Force-Deflection Spectroscopy for measuring the mechanical properties of nanowires. This last technique is implemented with an AFM and a simple "nanomechanics" workbench fabricated using photolithographic methods.

Monday, Feb 6 2006

Who Will Make Tomorrow's Discoveries?

Dr. Stephon Alexander is one of the National Geographic Society's Emerging Explorers. He is exploring the secrets of the early universe, at the intersection of fundamental physics and cosmology. More...

Wednesday, Jan 18 2006

Frustration

When a number of interactions compete within a system they can't all prevail, so the resolution of 'frustrated' forces is an important determinant of the overall behaviour of a system. In particular, geometrical frustration among spins in magnetic systems can lead to exotic effects such as 'spin ice', a state where atomic magnetic moments mimic the frustration of hydrogen ion positions in water ice. Wang et al. have created artificial spin ice using lithographically fabricated arrays of nanoscale magnets. Magnetic moments in the lattice follow the two [pointing]-in/ two-out 'ice rule' typical of spin ice. With this model it is possible to study frustration in great detail; this is relevant to magnetic recording, where ferromagnetic elements are being pushed to ever higher densities. On the cover, a magnetic force microscopy representation of the magnetization pattern of artificial spin ice: plateaus and valleys show regions of opposite magnetization. More...

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