Harvard University Department of Physics

The Morris Loeb Lecture in Physics: Marc Mézard

Colloquium (Apr 28): "The spin glass cornucopia"
Lecture I (Apr 29): "Phase transitions in hard computer science problems"
Lecture II (Apr 30): "Occam’s razor in massive data acquisition: a statistical physics approach"

Reunion and Symposium for Graduate Alumni

On Friday, April 4, 2014, Harvard celebrated the venerable history of one of the country’s great physics programs.

Fall 2013 Certificate of Distinction in Teaching Awards

Graduate students Prahar Mitra, Elliot Schneider, Elizabeth Petrik, Nicholas Schade, Alexandru Lupsasca, Chi-Ming Chang, and Timothy Koby have been awarded the Harvard University Certificate of Distinction in Teaching for the Fall 2013 term by the Derek Bok Center.

First Direct Evidence of Cosmic Inflation

The BICEP2 Collaboration, led by Professor John Kovac, has announced the discovery of first direct evidence of cosmic inflation, the expansion of space first proposed in 1981 by Alan Guth of MIT. Watch the VIDEO.

EPiQS Funding to Boost Quantum Materials Theory Research

Harvard has been chosen one of the six receipients of Gordon and Betty Mooore Foundation's Emergent Phenomena in Quantum Systems (EPiQS) grants...

Dark Matter as a Trigger for Periodic Comet Impacts

Professors Lisa Randall and Matthew Reece suggest that a smooth disc of dark matter passing through the Galaxy approximately every 35 million years might be the underlying cause of the cycles of increased meteorite activity on Earth, such as the one that led to the extinction of the dinosaurs...

SPOTLIGHT ON...

Professor Eric Mazur has published a groundbreaking, modern introductory physics textbook that builds up physics from conservation principles: Principles & Practice of Physics (Pearson, 2014).

"When students focus just on the equations they do not necessarily understand the concepts… What I found out was that, if you focus on solid conceptual understanding, students will not only get a better understanding of physics as a whole and appreciation of physics as a whole, they will actually perform better on traditional textbook problems…"
Watch Prof. Mazur's presentation and learn more about the book on the Publisher's website.

UPCOMING EVENTS

Tomorrow

Physics Colloquium Tea
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"Föppl, Fluctuations, and Feynman: Nonlinear Mechanics with Graphene and Nanotubes", Paul McEuen, Cornell University
- A carbon nanotube or graphene sheet can easily be many millions of times longer in one direction than another. This, combined with their diminutive size, makes them very interesting mechanical objects. Thin 2D structures, first studied in detail by August Föppl over a hundred years ago, are notoriously difficult to understand. The problem gets more interesting with graphene and nanotubes, as they undergo thermal fluctuations in their low energy modes that completely alter their emergent “macro” properties.
  
  In this talk, we will discuss experiments to probe these effects. First, individual nanotubes are picked up and strained with micron-sized tweezers, allowing us to simultaneously study the optical, electronic, and vibrational properties of these molecular rods. Similar tricks are performed with graphene. These experiments allow us to test decades-old predictions of the effects of fluctuations on Föpply structures and also create nanoscale optomechanical systems with record low masses. Finally, we discuss how the Japanese paper art of Kirigami (combined with 2D materials) offers a route to meeting Feynman’s last, as yet unmet, challenge: the construction of nanoscale machines.
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Tuesday, April 22nd

Michael Ramsey-Musolf (UMass-Amherst) "Electroweak baryogenesis: Searching for new scalars and new CPV"
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Wednesday, April 23rd

Special CMP Seminar: Saad Zaheer, University of Pennsylvania
- Title: Three dimensional Dirac semimetals
  
  Abstract: Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments.
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HQOC/ITAMP JQS Seminar - Igor Lesanovsky, University of Nottingham
- Igor Lesanovsky, University of Nottingham
  Talk Title: Out-of-equilibrium dynamics of strongly interacting Rydberg gases in a
  dissipative environment
  
  The most recent generation of cold atom experiments uses
  atoms in Rydberg states to explore many-body phenomena. In this talk I
  will focus on the non-equilibrium dynamics of such systems where
  non-trivial behaviour is generated by the competition between coherent
  laser excitation, dissipation and the strong interaction between Rydberg
  atoms. I will discuss the relaxation of Rydberg lattice gases, showing
  that it is hierarchical and strongly correlated. This establishes a
  connection to kinetically constrained systems that are used in soft
  condensed matter physics as models for the description of glassy phenomena.
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LPPC Seminar: The nuPRISM detector: An experimental solution to the neutrino energy measurement problem - Mike Wilking (TRIUMF)
- The frequency with which a neutrino oscillates is dictated by its energy. Therefore, in order to determine neutrino oscillation parameters, experiments must accurately measure the energy of each neutrino. Unfortunately, neutrino energy is not directly observable, and, instead, experiments can only measure the outgoing charged lepton from a charged current neutrino interaction, and perhaps some constraint on the energy of the final state hadrons. To translate these measurements to neutrino energy, it is necessary to rely on theoretical models of neutrino interactions with atomic nuclei.
  
  In recent years, neutrino interaction models have undergone drastic modifications. Many models now predict that neutrinos interact with correlated sets of nucleons within the nucleus, which causes large biases in reconstructed neutrino energy for 20-30% of interactions at neutrino energies near 1 GeV. These effects were not included in the state of the art neutrino models just 5 years ago. These nucleon correlation effects are difficult to calculate, and large discrepancies exist between currently available models. This results in large systematic uncertainties in neutrino oscillation experiments, the size of which cannot be determined from a comparison data.
  
  The nuPRISM concept places a detector ~1 km from the neutrino production source that spans a range of off-axis angles relative to the neutrino beam direction. As the off-axis angle changes, the beam energy changes, which can provide a direct, data-driven constraint on the relationship between neutrino energy and experimental observables. This technique is currently being pursued as a near detector upgrade for the T2K experiment, but it is generally applicable to all long-baseline neutrino experiments.
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Ken Kamrin; MIT
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Thursday, April 24th

CMP Seminar: Koenraad Schalm, Leiden and Harvard
- Title: Far from equilibrium energy flow in quantum critical systems
  
  Abstract: We investigate far from equilibrium energy transport in strongly coupled quantum critical systems. Combining results from gauge-gravity duality, relativistic hydrodynamics, and quantum field theory, we argue that long-time energy transport after a local thermal quench occurs via a universal steady-state for any spatial dimensionality. This is described by a Lorentz boosted thermal state. We determine the transport properties of this emergent steady state, including the average energy flow and its long-time fluctuations.
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Joint Harvard / MIT Seminar: Hirosi Ooguri (Caltech)
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Saturday, April 26th

Engineering and Physical Biology Annual Symposium
- On Saturday, April 26, the annual Engineering and Physical Biology (EPB) Symposium will be held in Room B103 of the Northwest Building, 52 Oxford St. Speakers from constituent fields -Physics, Engineering, Chemistry and Molecular Biology - will present significant recent findings ranging from the physics of protein conformation to DNA knotting.
  
  As in the past, the EPB Symposium day has been organized to bring together students and faculty from three Harvard areas (MCB, Physics and SEAS) with outstanding visiting scholars. (For a review of last year’s Symposium, see https://www.mcb.harvard.edu/mcb/news/news-detail/3684/symposium-features-physical-biology-research/) EPB is now in its eighth year as a PhD track for students wishing to “probe living systems through the lens of physics and engineering.”
  
  The day will be divided into two parts. The morning (until 12:30 pm) will be a public symposium featuring four visiting faculty. (See poster to your right) The public is welcome to attend, and the talks should be of wide interest to the Harvard science community.
  
  The afternoon will feature graduate student presentations and discussions in a more intimate setting that should promote the cross-fertilization of disciplines that EPB encapsulates. (These sessions will not be open to the general public.)
  
  Work at physics and engineering interface is rapidly becoming an established part of the life sciences. EPB particularly welcomes members of the MCB community to engage with these speakers working on the frontiers of physical biology.
  
  Morning Schedule - Public Event:
  
  9:00 - 9:45:
  Marco Foiani Prof. of Molecular Biology, Dept. of Biosci., University
  of Milan and IFOM-IEO “Mechanosensing at the nuclear envelope: an ATR-mediated
  response to control cell plasticity”
  
  9:45 – 10:30
  Kerry Bloom Dept. of Biology, Univ. of North Carolina, Chapel Hill
  "The landscape of forces in mitosis"
  
  10:30 – 11:00 Coffee Break
  
  11:00 – 11:45
  Jonathon Howard Eugene Higgins Prof. of Molecular Physics & Biochem., Yale University
  and Max Planck Inst., Dresden "Ciliary and flagellar motility: From single molecules to
  collective motion"
  
  11:45 – 12:30
  Olaf Sparre Andersen Prof. of Physiol. & Biophys., Weill Cornell Medical College
  "Interactions of drugs and other amphiphiles with membranes: Implications for membrane
  protein function and drug development"
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