January 29
Distinguished University Professor Lecture
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**Canceled due to inclement weather**
Ted Jacobson, University of Maryland
Hawking radiation in a laboratory!?
Einstein's theory of gravity opened Pandora's box of warped spacetime in 1915, and out popped the black hole, confusing and delighting (or maddening) physicists ever since. In the early 1970's it was discovered that black holes have entropy and temperature, and decay by Hawking radiation, like radioactive whirlpools in the spacetime river, raising two persistent puzzles: the black hole information paradox and the transPlanckian problem. To bring some of this down to earth, Unruh in 1980 conceived of a black hole analog, formed by a flowing, quantum fluid, which might one day be studied in a laboratory. That day has now come...probably. In the last few years, Jeff Steinhauer has carried out a number of experiments on Bose-Einstein condensates of rubidium atoms, configured to emulate a black hole, and reported on the observation of thermal phononic Hawking radiation and its quantum entanglement with phonons inside the sonic black hole. In this colloquium I will describe these ideas and experiments, as well as simulations that have been carried out in order to help understand what has so far been observed.
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February 5
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Charlie Tahan, The Laboratory for Physical Sciences
Hosted by Brian Swingle
The Laboratory for Physical Sciences: Past, Present, and Future
For over 60 years the Laboratory for Physical Sciences, in partnership with the University of Maryland, has advanced the physics and engineering behind information science and technology. A unique organization where university, industry, and federal government scientists collaborate on research in advanced communication, sensing, and computer technologies, the LPS currently houses four main divisions: Solid-State and Quantum Physics, Optical and RF Innovations, Microelectronics Integration, and Advanced Computing Systems. In this talk I will review the current interests and possible future directions of LPS while interjecting some of the unique history and impact that the Lab and UMD have shared over the years.
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February 12
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Patricia Falcone, Lawrence Livermore National Laboratory
Hosted by Howard Milchberg
Science and National Security
The quality, scope, and impact of U.S. science and technology is admired the world over. International scientific collaborations highlight key values including evidence, peer review, transparency, teamwork, and dialog. Scientific leadership and technological prowess are also elements of national power and national security for the U.S. and for other nations. Today, roughly half of U.S. government funded research and development is carried out in support of national security missions. Such research is supported to enable the government to make informed assessments, to develop and deploy defensive technology and systems, and to undergird effective offensive systems. A perspective on effective approaches for reaping national security benefits from open science, discovery, applied research, and innovation will be offered with examples from some current dual use domains.
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February 19
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Paul Corkum, National Research Council of Canada & University of Ottawa
Hosted by Howard Milchberg
A Plasma Perspective on Attosecond Science in Solids and in Gases
Ionization turns an atomic or molecular gas into a plasma with initial plasma parameters determined by atomic or molecular ionization physics. This obvious symbiosis encourages us to explore atomic ionization from a plasma perspective. When atoms are irradiated with intense light. That means that one should follow the sub-cycle motion of the newly formed electron (as one might for a plasma electron). The electron oscillates in the intense field, and it can collide with a near-by ion during this motion. In a plasma similar motion leads to inverse Bremsstrahlung, but in an atomic gas, high harmonics and attosecond pulses are produced provided the collision is between the electron and its parent ion. In this re-collision, infrared light is converted into much shorter wavelength light. Thus plasma physics leads us to a new form of extreme nonlinear optics.
I will describe attosecond pulse generation and measurement in solids and gases and why it is important.
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February 26
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Geoff Greene, University of Tennessee & Oak Ridge National Laboratory
Hosted by Carter Hall & Betsy Beise
The Neutron Lifetime “Problem”
Within a nucleus, the neutron may be unconditionally stable. However, when liberated from a nucleus, the neutron is unstable and beta decays with a lifetime of approximately 10 minutes. Since neutron decay is the simplest example of nuclear beta decay, the value of the neutron lifetime is a parameter of considerable importance to a wide variety of physical systems. These range from astrophysics to particle physics to cosmology. Particularly noteworthy is role played by the neutron lifetime in the Big Bang where it sets the time scale for nucleosynthesis and thus determines the cosmic abundance distribution of light elements. Given the interest in the neutron lifetime, it is somewhat distressing to observe that the measurements of the neutron lifetime having the lowest quoted uncertainties are in substantial disagreement with one another. After a brief overview, I will discuss this “neutron lifetime problem,” outline the experimental landscape, and conclude with the prospects for future experiments.
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March 5
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Surjeet Rajendran, University of California, Berkeley
Hosted by Raman Sundrum
Quantum Sensors and Dark Matter Detection
The last two decades have witnessed rapid developments in quantum sensing, enabling precision measurements of time, acceleration and magnetism. These sensors seem well suited to dramatically extend current experimental probes of dark matter. For example, these techniques can search for light dark matter in the mass range 10^(-22) eV - 1 GeV, while also being able to probe certain kinds of ultra-heavy dark matter in the mass range 10^(18) GeV - 10^(33) GeV. This broad search for dark matter, well beyond the well explored WIMP paradigm, is necessary since observational constraints on the mass of dark matter allow it to lie anywhere between 10^(-22) eV - 10^(48) GeV, with a number of theoretically well motivated candidates spanning this vast range. In this talk, I will discuss these experimental methods and highlight recent experimental progress in their implementation. In addition, I will also touch on their potential application to direct laboratory searches of dark energy.
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March 12 (John S. Toll Physics Bldg., Room 1412)
Dedication of Weber Memorial Garden
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Rainer Weiss, Massachusetts Institute of Technology
What Joe Weber Started: Gravitational Wave Astronomy
The talk begins with some history of the new field followed by a brief description of the technology that was required to succeed. A summary of the discoveries and a view to the future will end the talk.
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March 26
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Jeff Bub, University of Maryland
Totally Random: Why Nobody Understands Quantum Mechanics
This is a talk about a graphic novel — a comic — I wrote with my daughter about quantum mechanics, and why someone like Richard Feynman, who won the Nobel prize in 1965 for his contribution to quantum electrodynamics, could say that ‘nobody understands quantum mechanics.’ Totally Random, published last year by Princeton University Press, focuses on entanglement: what it is, why it’s puzzling, and what you can do with it. Schrödinger, who came up with the term, called entanglement 'the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought.' I’ll talk about some of the difficulties writing a science comic, particularly one aimed at explaining entanglement to a general audience, how we deal with entanglement and some foundational questions about quantum mechanics, and how a comic can explain some of the core ideas behind quantum computation and quantum cryptography.
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April 2
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Tom Faulkner, University of Illinois at Urbana-Champaign
Hosted by Brian Swingle
Quantum Information, Causality and Negative Energy
Negative energy density can arise naturally in Quantum Field Theory - the theoretical framework with which we describe fundamental particle physics and the matter which makes up our universe. However too much negative energy density can lead to pathologies when coupling this matter to gravity via Einstein’s equations. In this talk I will discuss conjectured bounds on negative energy density that can rule out such pathologies and sketch very recent general proofs of these bounds. The methods we use combine causality considerations with concepts taken from the study of quantum information. I will discuss how this provides further evidence for deep connections between gravity and quantum information.
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April 9 (John S. Toll Physics Bldg., Room 1412)
Carr Lecture
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Gregory S. Boebinger, U.S. National High Magnetic Field Laboratory and Florida State University and the University of Florida
Exploring the Heart of Quantum Matter with Extreme Magnetic Fields
In Quantum Matter, intrinsic electronic charges and magnetic fields conspire in strange and weird ways to create new materials properties. High magnetic fields are uniquely positioned to probe the mysteries that remain at the heart of Quantum Matter, where Nature creates 1/3 fractional electric charges, “spin liquids” of fixed charges but mobile magnetic fields, and high-temperature superconductivity in which the very existence of electrons as particles becomes suspect.
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April 16 (John S. Toll Physics Bldg., Room 1412)
Irving and Renee Milchberg Lecture
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Susan Eisenhower
Lessons from 1945: Ethics, the War in Europe, and its Enduring Legacy
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April 23
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Vlad Manucharyan, University of Maryland
Physics and Applications of Quantum Superconducting Circuits
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April 30
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Anson Hook, University of Maryland
The search for Axions
The axion is one of the favorite candidates for dark matter as it is a dark matter candidate that simultaneously also explains why the neutron electric dipole moment is small. One of the most interesting thing about axions are the many and varied ways in which it can be searched for. We describe a few of these methods ranging from laboratory based experiments such as cavities and interferometers to astrophysical systems such as white dwarfs and neutron stars.
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May 7
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Santo Fortunato, Indiana University
Hosted by Victor Yakovenko
Science of Science
Science of science is the study of the activity of science makers, via their production, citation, collaboration, funding, and mobility patterns. Here I will present findings on citation dynamics and productivity. The distribution of the number of citations of papers published in the same year and discipline follows a universal curve, if the number of citations is properly rescaled. This allows for unbiased comparisons of the citation-based impact of works in different disciplines. I will introduce key mechanisms behind citation dynamics, like preferential attachment and knowledge obsolescence, and show that scientific reputation can artificially boost the impact of a work. The exponential growth of scientific output has two major consequences (among others): papers are forgotten faster and faster and there is citation inflation, i.e. the value of a citation decreases in time.
Finally I will prove that you will never get the Nobel Prize, sadly.
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