<![CDATA[Condensed Matter Theory Research at UVM]]> http://www.uvm.edu/cmt en-us Tue, 21 May 2013 12:02:54 -0400 <![CDATA[Electronic Conduction at the Edge]]> http://www.uvm.edu/cmt?Page=news&storyID=16014&category=cmt Thu, 02 May 2013 00:00:00 -0400 http://www.uvm.edu/cmt?Page=news&storyID=16014&category=cmt An international team of researchers including Prof. Adrian Del Maestro at the University of Vermont may have uncovered a way to improve the efficiency of proposed future electronics built from the edges of a new class of exotic materials.  In conventional electronic circuitry, electrons move through crystalline wires but their flow is impeded by scattering off defects producing a finite resistance.  Topotronics employ quantum mechanical degrees of freedom which allow for highly conducting dissipation free channels at the surface of materials which would otherwise be insulating in their bulk. In a paper appearing in the journal Physical Review B, Prof. Del Maestro and his collaborators have shown that the spin polarization of electrons at the surface of a topological insulator made from mercury and tellurium makes them susceptible to a different type of scattering due to the magnetic interaction between electrons and the fixed mercury nuclei.  By building topotronics with isotopes that do not contain any nuclear spins, conducting wires could made with vanishingly small electrical resistance leading to applications including better batteries and more efficient computers.

]]> <![CDATA[Dr. Chris Herdman Joins the CMT Group]]> http://www.uvm.edu/cmt?Page=news&storyID=14697&category=cmt Tue, 30 Oct 2012 00:00:00 -0400 http://www.uvm.edu/cmt?Page=news&storyID=14697&category=cmt Dr. Chris Herdman has joined the CMT group as a postdoctoral research associate working with Prof. Adrian Del Maestro.  He received his PhD in physics from the University of California, Berkeley in Birgitta Whaley's group, where his research focused on the intersection of condensed matter physics and quantum computation. His research interests include studying quantum phases of matter with computational methods; and he is especially interested in exotic quantum phases  and their application to quantum computation. 

Before joining the CMT group, he has primarily focused on studying so-called topological phases of matter; such exotic quantum phases of matter have been proposed as the basis of a quantum computer. In particular, he developed and used quantum Monte Carlo methods to study topological phases of quantum dimer models. Additionally, he has worked on developing approaches to robustly generate topological phases in experimental systems, such as neutral atoms trapped in an optical lattice.

]]> <![CDATA[PhD Student Max Graves Selected as Student Poster Competition Finalist]]> http://www.uvm.edu/cmt?Page=news&storyID=14495&category=cmt Fri, 05 Oct 2012 00:00:00 -0400 http://www.uvm.edu/cmt?Page=news&storyID=14495&category=cmt UVM Materials Science PhD student Max Graves was selected as one of five finalists in the physical science, mathematics and engineering category at the President's Student Poster Competition on Wednesday October 3rd.

Max's poster, entitled "Path Integral Monte Carlo Study of Proximity Effects in Confined Helium-4" displays his recent numerical work on how the thermodynamic properties of Helium-4 atoms confined to localized regions of space are affected by coupling to neighboring regions at low temperatures. This study was motivated by recent experiments performed by the Gasparini group at SUNY Buffalo that showed that Helium-4 under these conditions exhibits an enhanced superfluid response as well as an excess specific heat. 

Max and Prof. Del Maestro believe that these strange phenomena are due to the intrinsic indistinguishability of the bosonic Helium-4 atoms, and they plan to test their hypothesis by studying both quantum and classical atoms.  For the classical distinguishable atoms, they conjecture that this exotic behavior should be absent, and that the phenomena is a macroscopic manifestion of quantum mechanics.

]]> <![CDATA[Superreflective Surfaces for Ultracold Matter Waves]]> http://www.uvm.edu/cmt?Page=news&storyID=14371&category=cmt Tue, 18 Sep 2012 00:00:00 -0400 http://www.uvm.edu/cmt?Page=news&storyID=14371&category=cmt Researchers in the Department of Physics at the University of Vermont (UVM) predict that it is now possible to create surfaces that are perfectly reflecting for slow moving atoms and molecules.  

In a paper that has just been published in Physical Review Letters, Prof. Dennis Clougherty and recent Materials Science PhD graduate Yanting Zhang calculate that a quantum phase transition at low temperatures can change a sticky surface to a perfectly reflecting one.  The work has potential applications to the emerging field of atom optics, where ultracold matter waves are controlled and processed in a similar way to light waves in conventional optics.

]]> <![CDATA[A One Dimensional Quantum Liquid of Helium]]> http://www.uvm.edu/cmt?Page=news&storyID=14163&category=cmt Mon, 13 Aug 2012 00:00:00 -0400 http://www.uvm.edu/cmt?Page=news&storyID=14163&category=cmt In the latest issue of International Journal of Modern Physics B, Prof. Adrian Del Maestro has confirmed that when indistinguishable atoms of helium-4 are confined to flow inside cylindrical cavities (pores) with a radius approaching a single nanometer they act very differently than in three spatial dimensions.  Using large scale computer simulations, he has shown that helium atoms at the center of pore simultaneously exhibits the properties of both a liquid and a solid and can collectively support low energy gapless excitations.  

This exotic state of matter is known to theorists as a Luttinger liquid and can be fully understood through the use of quantum hydrodynamics.  Prof. Del Maestro describes how this special liquid behaves when the radius of the pore is altered and hopes that his results will lead to the experimental detection of this exotic state of matter.

]]> <![CDATA[Complex Materials REU Program a Success!]]> http://www.uvm.edu/cmt?Page=news&storyID=14164&category=cmt Mon, 13 Aug 2012 00:00:00 -0400 http://www.uvm.edu/cmt?Page=news&storyID=14164&category=cmt The Summer REU program on Complex Materials supported by the National Science Foundation finishes off with a bang on Friday August 10th with student presentations.

Andrew Geragotelis spoke about his work with Prof. Dennis Cloughery on "Investigating the Sticking of Hydrogen on Graphene" and Andrea Rommal of Muhlenberg College discussed her summer research on "Corrections to Helium-­4 Chemical Potential at the Superfluid Transition" completed under the supervision of Prof. Adrian Del Maestro.

Congratulations to all participants in the REU Complex Materials program, everyone had an stimulating and productive summer.

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