This colloquium aims to explain why classical thermodynamics is insufficient for solids. After a review of classical equilibrium and non-equilibrium thermodynamics, two examples will be considered, grain growth and crystal plasticity, the latter one in more details. The major complication for development of thermodynamic theory for these cases was the lack of understanding of phase flow geometry. Recently, this geometry was described for dynamics of edge dislocations. Based on this finding, thermodynamics of crystal plasticity can be constructed. It includes two new thermodynamic parameters, entropy and temperature of microstructure.They have simple physical meaning: the rate of microstructure entropy coincides with the rate of slip avalanches while microstructure temperature is average energy drop in a slip avalanche. Perhaps, the phase flow geometry and the corresponding thermodynamic are common for many avalanche-type phenomena.
We set out to combine a mechanical system in which classical mechanics breaks down and quantum mechanics must be used with a seemingly unlikely application, measurement of the strength and effects of gravity. Our optomechanical system consists of a silica microsphere levitated in ultra-high vacuum in a magneto-gravitational trap. The microsphere is trapped in a magnetic field gradient created by permanent magnets and ferromagnetic pole pieces using the weak diamagnetism of the particle. With optical position measurements and feedback, the mechanical motion can be cooled by several orders of magnitude, ideally reaching the quantum ground state. The extreme sensitivity of this optomechanical system to external forces makes it a promising approach to a new measurement of the Newtonian gravitational constant. Furthermore, by measuring the decoherence rate of non-classical motional states of the trapped particle, it may be possible to place limits on theories of gravitational decoherence. This material is based upon work supported by the National Science Foundation under Grant No. 1757005
Giannis Mpourmpakis and his students have proposed a bond-centric (BC) model able to capture cohesive energy trends over a range of monometallic and bimetallic nanoparticles and mixing behavior (excess energy) of nanoalloys, in great agreement with DFT calculations. This model utilizes to calculate the energetics of any nanoparticle morphology and chemical composition, thus significantly accelerating nanoalloys design. This work introduces a simple yet very powerful tool for nanoalloy design that can potentially help elucidate the energetics of alloy MNP genomes.
Quantum mechanics is a strange theory, and it has been used to justify all manner of religious claims such as extra-sensory perception. This year we bring together five experts on the physics of quantum mechanics to discuss what we know and what we don’t know. We will work both to make the basic laws of quantum mechanics accessible to the non-expert, while at the same time addressing cutting-edge debates in the philosophy and application of quantum physics.
James R. Martin II, the Bob Benmosche Professor and Chair of the Glenn Department of Civil Engineering at Clemson University, has been named dean of the University of Pittsburgh’s Swanson School of Engineering, Pitt Provost and Senior Vice Chancellor Patricia E. Beeson announced today. He will begin his deanship on August 15.
The nature of dark matter is one of the most important open problems in modern physics. Axions, originally introduced to resolve the strong CP problem in quantum chromodynamics (QCD), and axion-like particles (ALPs) are strongly motivated dark matter candidates. Nuclear spins interacting with axion-like background dark matter experience a torque, oscillating at the axion Compton frequency. The Cosmic Axion Spin Precession Experiments (CASPEr) use precision magnetometry and nuclear magnetic resonance (NMR) techniques to search for the effects of this interaction. CASPEr has the potential to...
Michael Widom and his colleagues showed what happens at the grain boundaries of one particular alloy of the metals nickel and bismuth that makes it brittle in their paper published in Science. Using advanced electron microscopes, Widom’s collaborators at Lehigh University scrutinized these microscopic grain boundaries at an atomic level. In a "very heroic experimental program" they discovered that when grains met, the bismuth and nickel atoms realigned into lattices to form layered superstructures at the grain boundaries. These superstructures had previously been thought to exist only rarely in some alloys. Finding it at many different boundaries led the team to conclude that these superstructures are probably much more common than many people had thought.
The Osher Lifelong Learning Institute (OLLI) at Pitt is seeking course proposals for its Fall 2018 Term. OLLI courses are typically 1x a week for 5 weeks. Each term offers 2 sessions of courses. We seek course proposals in a variety of areas including: literature, history, political science and government, the arts, sciences, languages and more. Most OLLI designed courses are similar to actual college courses (but no tests or grades, abbreviated content, and shortened to run for 5 weeks).
OLLI Instructors are often university professors and instructors, visiting lecturers, Postdoctoral fellows, and others with content and teaching expertise. Instructors in the program are paid. Course proposals for Fall term are due by April 27.
PQI always assists to organize an educational and informative visit in the development of Quantum Science, encouraging the collaborations between various industry and academia.
On March 9th, 2018, four students and one postdoc from University of Pittsburgh were invited to visit Google Quantum-Hardware lab at UC Santa Barbara which was organized by PQI. Eric Ostby and Pedram Roushan, Research Scientists at Google were helped us to arrange this visit.
Google's research team do work hard to build a quantum computer which will be millions of times more powerful than today’s supercomputers. Such visit helps to initiate more academic people to get involved in such projects, playing a hub role for quantum technologies.