News Archive:
- 10/14/22:
Colloquium:
SaulsFest 2022 --
The Left Hand of the Electron, Northwestern University, October 14-15, 2022.
Abstract:
Parity violation by the weak force was demonstrated in an experiment led by Chien-Shiung Wu in 1957 on the asymmetry of electron currents emitted in the beta decay of polarized 60Co. The asymmetry reflected two broken symmetries - mirror refelctions and time-reversal, the latter imposed by an external magnetic field. That same year Bardeen, Cooper and Schrieffer published the celebrated BCS theory of superconductivity, and soon thereafter Anderson and Morel proposed that the ground-state of liquid 3He was likely a BCS condensate of chiral molecular pairs of Helium atoms, exhibiting spontaneously broken mirror reflection and time-reversal symmetries. I discuss the physics behind this phenomenon, its discovery and specifically how broken symmetry and topology of the superfluid vacuum conspire to endow electrons in the chiral vacuum with ``handedness''.
[Slides and Photos]
.
- 10/4/22:
Invited talk: DaleFest2022 --
Phase-sensitive Transport in Josephson Weak Links & Junctions
celebrating Dale Van Harlingen's Career at UIUC,
September 29-October 1, 2022.
Abstract: In recognition of Dale's many accomplishments in the field of superconductivity and quantum device measurements I present some ideas, and yet to-be-tested theoretical predictions for phase-sensitive charge and heat transport in Josephson devices ranging from Sharvin contacts to weak-link channels.
[Slides and Photos]
.
- 9/16/22:
New Appointment:
Wonderful invitation and opportunity from the physics and astronomy faculty, the college of science and office of research at LSU! ... Exciting times for quantum physics at the flagship research university in Louisiana!
[announcement]
.
- 2/21/22:
New Publication:
Theory of Disordered Superconductors with Applications to Nonlinear Current Response,
Prog. Theor. and Expt. Phys. 2022, 3, 033I03 (2022).
I discuss the pair-breaking effect of disorder on the current response, including the nonlinear current response to an electromagnetic field are reported. The nonlinearity is shown to lead to source currents for photon generation and nonlinear Kerr rotation driven by the nonlinear response to excitation of the superconductor by a multi-mode electromagnetic field. The relevance of the nonlinear source currents to superconducting radio-frequency cavities as detectors of axion-like dark matter candidates are discussed.
- 6/15/22:
New Publication:
My retrospective on early extensions of the microscopic theory of superconductivity and superfluidity with complex patterns of symmetry breaking and emergent ground-state topology. The story begins circa 1961, but highlights the watershed paper by Balian and Werthamer on spin-triplet, p-wave superconductivity in 1963. Then I endeavor to explain key aspects of the physics that was discovered experimentally and theoretically over the next 5 decades. Among the early discoveries were those by the Cornell low temperature groups led by David Lee and John Reppy. This article is written in honor of their impact on low temperature physics and superfluidity of the Helium liquids in particular.
[arXiv & JLTP].
[All access link from Springer]
- 2/08/22:
New Publication:
Effects of Incipient Pairing on Non-equilibrium Quasiparticle Transport in Fermi Liquids
Prog. Theor. and Expt. Phys. 2022, 3, 033I02 (2022).
We develop the theory of quasiparticle transport for Fermi liquids in the vicinity of a BCS-type superfluid transition starting from Keldysh's field theory for non-equilibrium, strongly interacting fermions. The leading corrections to Fermi liquid theory for non-equilibrium quasiparticle transport near a Cooper instability arise from the virtual emission and absorption of incipient Cooper pairs. The theory is applicable to quasiparticle transport in superconductors, nuclear matter and the low temperature phases of liquid 3He. As an implementation of the theory we calculate the pairing fluctuation corrections to the attenuation of zero sound in liquid 3He near the superfluid transition and demonstrate quantitative agreement with experimental results.
- 5/8/21:
Joseph William Serene --
Joe passed away on May 1, 2021. His academic career was remarkable in its breadth. He was a brilliant physicist, dedicated teacher, skilled administrator, wonderful father, husband and friend who taught and led by example.
[read more]
.
- 8/26/20:
Northwestern University is key partner with Fermilab in a new national Center for Superconducting Quantum Materials and Systems, with $115 million from the DOE over five years, to build beyond-state-of-the-art quantum computers based on superconducting technologies, and to develop superconducting quantum sensors that could lead to the discovery of the nature of dark matter.
Press Release
.
- 4/21/20:
Physicist Jim Sauls takes a dip into the weird world of quantum liquids and ``quantized vortices.''
His findings could lead to advanced technologies based on superfluids, cold atomic gases, and superconductors.
Press Release
.
- 4/13/20:
CAPST Research:
Wave Ngampruetikorn and James Sauls published new theoretical predictions of a
Zero-Field Thermal Hall Effect as a signature of a
broken P and T ground state in Topological Superconductors.
Phys. Rev. Lett. 124, 157002 (2020)
.
- 3/15/20:
Theory-Experimental Collaboration reports discovery of
Broken time-reversal symmetry in the topological superconductor UPt3,
Nature Physics (2020)
.
- 1/27/20:
PhD Candidate Robert Regan and J. A. Sauls published new theoretical predictions for the equilibrium
and meta-stable vortex phases of rotating superfluid 3He-B,
Physical Review B 101, 024517 (2020)
.
- 12/3/19:
The Osaka University team led by Professor Takeshi Mizushima in collaboration with J. A. Sauls, publish
new theoretical research on a class of Topological superconductors:
Chiral Higgs Mode in Nematic Superconductors in
Physical Review Letters, 123, 237001 (2019)
.
- 11/8/19:
Press Release: ``Dirty'' Superconductors Make Better Particle Accelerators
CAPST researchers Wave Ngampruetikorn and Jim Sauls show how impurities infused into the surface of Niobium can increase the maximum accelerating field of superconducting radio-frequency cavities, a finding with huge potential cost advantages.
].
- 08/29/19:
Wave Ngampruetikorn & J. A. Sauls publish
Effect of inhomogeneous surface disorder on the superheating field of superconducting RF cavities as a Rapid Communication in the inaugural issue of
Physical Review Research 1, 012015 (2019).
- 08/16/19:
Physicists Reveal New Understanding Of Quantum Mechanics In Circuits:
Xinyuan You, Jens Koch & J. A. Sauls (CAPST) publish a major advancement on the quantum theory of electrical circuits in
Physical Review B.
[read more].
- 10/28/19:
A Week of Breaking News in Quantum Computing
was preceded by the Lawrence B. Dumas Domain Dinner on ``Innovating for Second Quantum Revolution''
with a presentations by members of INQUIRE, the
Initiative at Northwestern for Quantum Information Research and Engineering
, including Jim Sauls presenting the status and promise of Quantum Computing
[
Presentation Slides
].
- 08/29/19:
Wave Ngampruetikorn & J. A. Sauls publish
Effect of inhomogeneous surface disorder on the superheating field of superconducting RF cavities as a Rapid Communication in the inaugural issue of
Physical Review Research 1, 012015 (2019).
- 03/09/19: J. A. Sauls was elected Secretary-Treasurer of the [Division of Condensed Matter Physics] (DCMP) of the American Physical Society (APS) [read more].
- 12/15/18:
J. A. Sauls was appointed Specialty Chief Editor for Frontiers in Physics. [read more].
- 12/10/18:
Wei-Ting Lin presented his Prospectus for advancement to candidacy to the PhD.
- 11/01/18:
``Superfluid 3He in Confined Quarters'' published in the November issue of Physics Today (2018), W. P. Halperin, Jeevak Parpia and J. A. Sauls [read more].
- 7/27/18:
``Spontaneous Helical Order of a Chiral p-Wave Superfluid Confined in Nanoscale Channels'' published in Physical Review Letters, 121, 045301 (2018), J.J. Wiman and J.A. Sauls [read more].
- 7/25/18:
Joshua Wiman wins Best Poster Award titled ``Is Superfluid 3He-A the precursor to magnetically ordered solid 3He?'' at the International Symposium on QuantumFluids and Solids, Tokyo, Japan.
- 6/25/18:
Philosophical Transactions of the Royal Society A - Theme Issue ``Andreev Bound States'', published. Introduction: ``Andreev Bound States and Their Signatures'' by J. A. Sauls [read more].
- 12/16/17:
Robert Regan presented his Prospectus for advancement to candidacy to the PhD.
- 9/1/17:
Pallab Goswami of the Joint Quantum Institute at University of Maryland, joins the Faculty of Northwestern University
[read more].
- 8/15/17:
Bill Halperin and James Sauls receive the 2017 Fritz London Memorial Prize in Low
Temperature Physics at the 28th International Conference on Low Temperature
Physics held in Gothenburg, Sweden
[read more].
- 6/21/17:
Northwestern and Fermilab establish the
Center for Applied Physics & Superconducting Technologies
[Press Release].
- 6/16/17:
Hao Wu receives his Ph.D. for the Dissertation:
"Excitations in Topological Superfluids and Superconductors"
[PDF].
- 3/15/17:
CMT presentations at the March APS meeting, New Orleans
[CMT@APS2017]
- 3/2/17:
``On the Nambu Boson-Fermion Mass Relations'' published
[PRB 95, 094515 (2017)]
Last Updated: November 2017
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