Eric Sembrat's Test Bonanza

We are in the era of gravitational-wave and multi-messenger astronomy, kick-started by the Advanced LIGO and Advanced Virgo detectors. The Advanced detectors concluded their third observing run (O3) in March 2020. The latest catalog of compact binary coalescences from LIGO-Virgo-KAGRA contains 90 events with probability of astrophysical origin greater than 0.5. All events are believed to be mergers of neutron stars or / and black holes.

I will describe the analysis framework used to produce these catalogs and provide a summary of the observations and what we have learned from them. I will conclude by discussing improving the observing capabilities in the coming years.

Bio: Surabhi Sachdev is one of the lead analysts looking for gravitational-wave signals in the Advanced LIGO and Virgo data. She is currently a post-doctoral scholar at University of Wisconsin-Milwaukee. She received her PhD. in gravitational-wave Physics from CalTech in 2019, after which she was an Eberly post-doctoral fellow at the Penn State University. Her research interests lie in multi-messenger astrophysics, stellar astrophysics, cosmology, and science with future gravitational-wave detectors, such as LISA and the third generation ground based detectors.

LIGO and Virgo have observed over 80 gravitational-wave sources to date, including mergers between black holes, neutron stars, and mixed neutron star-black holes. The origin of these merging neutron stars and black holes -- the most extreme objects in our Universe -- remains a mystery, with implications for stars, galaxies and cosmology. Fortunately, the gravitational waves from these mergers encode their masses, spins and distances, which in turn encode how, where and when black holes and neutron stars are made. I will review the latest LIGO-Virgo discoveries and introduce how we extract astrophysical lessons from gravitational-wave data. I will then discuss some of the most exciting lessons, including mass gaps, evolution with redshift, and implications for cosmology. While the latest gravitational-wave observations have answered a number of longstanding questions, they have also unlocked new puzzles. I will conclude by discussing what we can expect to learn from future gravitational-wave and multi-messenger data.

Bio: Maya got her Ph.D. in Astronomy & Astrophysics from the University of Chicago in 2020, and is now a NASA Einstein Postdoctoral Fellow at Northwestern University. Her research interests include gravitational waves, compact objects, massive stellar evolution, and astrostatistics. Maya is leading efforts to understand the astrophysical and cosmological implications of black hole and neutron star gravitational-wave sources detected by LIGO and Virgo.

Abstract: In recent years, there have been rapid breakthroughs in quantum technologies that offer opportunities for fundamental physics discoveries and advanced understanding of basic quantum phenomena. In this perspective, first I will describe an application of atomic systems as quantum sensors for precision measurements of fundamental physics: atomic nuclear spin-dependent parity violation (NSD-PV) measurements. NSD-PV effects arise from exchange of the Z0 boson between electrons and the nucleus, and from interaction of electrons with the nuclear anapole moment, a parity-odd magnetic moment. We studied NSD-PV effects using diatomic molecules, where the signal is dramatically amplified by bringing rotational levels of opposite parity close to degeneracy in a strong magnetic field. I will present results that demonstrate sensitivity to NSD-PV surpassing that of any previous atomic PV measurement using the test system 138Ba19F, and discuss prospects of using this technique to measure aspects of the electroweak interaction that are difficult to determine with other methods.

In the second half, I turn to the basic tenet of quantum technologies: quantum measurement and quantum control. Ultracold atoms - our workhorse for quantum simulation, are an ideal platform for understanding the system-reservoir dynamics of many-body systems. Bose-Einstein condensates (BECs) offer multitude of non-destructive imaging methods, which are weak measurement techniques that yield a controlled reservoir and consequently allow time-resolved study of the system evolution paving the way for real-time control of quantum gases. To this end, I will describe our versatile high-resolution ultracold atom microscope: a combined hardware/software system that recovers near-diffraction limited performance and maximizes the information that is read out. Our high-fidelity digital correction technique reduces the contribution of photon shot noise to density-density correlation measurements which would otherwise contaminate the quantum projection noise signal in weak measurements. Finally, I will discuss the experimental characterization of the quantum projection noise from the measurement process.

Bio: Emine Altuntas is a postdoctoral researcher at the National Institute of Standards and Technology Gaithersburg and the Joint Quantum Institute in Dr. Ian Spielman's group. She received her B.A. from Amherst College in physics and political science in 2011. Subsequently she received her Ph.D. in 2017 from Yale University where in Prof. David DeMille's group she studied parity violation effects in diatomic molecules to characterize strong-force induced modifications of electroweak interactions. Her current research focuses on quantum backaction limited measurements in ultracold atoms towards the realization of open quantum systems. Her research interests include precision measurements of violations of discrete spacetime symmetries, and quantum measurement and quantum control with ultracold neutral atoms.

Prof. Martin Mourigal | School of Physics, Georgia Institute of Technology

Abstract: Magnetism is a fascinating phenomenon with roots in the ancient world. Although its precise understanding calls for relativistic quantum mechanics and field theory, it is integral to everyday technologies. In magnetic insulators, electrons are closely bound to a crystal lattice and carry strongly interacting magnetic dipoles; as a result, phases of matter with no classical analogs are possible. Such quantum magnetic phases are of great fundamental interest as a testbed of our understanding of many-particle quantum mechanics. In the first part of this lecture, I will discuss some of the central ideas in quantum magnetism, from the Heisenberg model to the more recent concepts introduced by Kitaev and others. Then, I will explain our research program to search for these simple models in bulk materials and understand their properties using neutron spectroscopy. Finally, I will discuss the challenges of utilizing these quantum magnets in electronic devices and beyond.

Bio: Martin Mourigal is an associate professor in experimental quantum condensed matter in the School of Physics. In addition, he serves as an advisor for the Institute for Materials and leads the Quantum Alliance of the Institute for Electronics and Nanotechnology.

Abstract: The field of Quantum Information is of great excitement in both fundamental physics and industry. One promising platform for quantum computing is gate defined quantum dot in semiconductors. The greatest limiting factor currently is that delicate quantum states can lose their quantum nature due to interactions with their environment. Other open challenges are to coherently control large scale spin qubits and develop methods to entangle quantum bits that are separated by significant distances.

Silicon-based materials are promising due to the long lifetimes of electrons’ quantum states, but also challenging due to the difficulty in fabrication and valley degeneracy. I will report a singlet-triplet qubit with a qubit gate that is assisted by the valley states. This work would potentially relax the design and fabrication requirement for scaling. Moreover, strong coupling between electron spins and photons in hybrid circuit-QED architecture has been achieved in this research field. Quantum optics, long distance quantum entanglement and communication via photons are promised. To address that, I will present my project on indium arsenate (InAs) double quantum dots (DQD) that are embedded in circuit-QED architecture. We demonstrated the direct evidence of photon emission from a DQD in the microwave regime. By achieving stimulated emission from one DQD in these works, we invented a semiconductor single atom maser that can be tuned in situ. I will demonstrate that a semiconductor based quantum dot is a promising platform for quantum information as well as for fundamental physics.

Bio: Yinyu Liu is a postdoctoral fellow at Harvard University and is leading a quantum information project in Professor Amir Yacoby’s group. She obtained her bachelor degree from Tsinghua University and completed her graduate work at Princeton University in the laboratory of Professor Jason Petta. Her PhD project focused on photon emission from semiconductor quantum dots integrated in a superconducting circuit quantum electrodynamics (cQED) architecture. Currently she is working on spin qubits fabricated from SiGe quantum wells, which enable longer lifetimes than other physical systems without sacrificing controllability.

Abstract: The deaths of massive stars seed our universe with black holes and neutron stars - the most exotic objects of the stellar graveyard. The births of these stellar remnants, as well as their mergers when paired in binaries, power explosions that can launch the most relativistic jets we know of in the universe (gamma-ray bursts) and shake the very fabric of space-time via ripples called gravitational waves. GW170817, the merger of two neutron stars witnessed through both its gravitational wave siren and its glow at all wavelengths of light, represents the first multi-messenger detection of one such extreme cosmic collision.

Starting from the example of GW170817, I will discuss how radio light in particular, and gravitational waves, can be used in tandem to unveil the physics of relativistic transients. I will also highlight opportunities and challenges that lie in front of us, as improvements in detectors’ sensitivities will transform a trickle of multi-messenger discoveries into a flood.

Biography: Alessandra Corsi is Associate Professor with a President’s Excellence in Research Professorship in the Department of Physics and Astronomy at Texas Tech University. Her research focuses on multi-messenger time-domain astronomy. She received her Laurea in Physics in 2003 and her Ph.D. in Astronomy in 2007 from the University of Rome Sapienza. She carried out post-doctoral research at various institutions including the California Institute of Technology. She joined Texas Tech as faculty in 2014. In 2015, she received an NSF CAREER award titled “CAREER: Radio and gravitational-wave emission from the largest explosions since the Big Bang”. She is a National (Italy) L’Oreal-Unesco awardee for Women in Science, a Fellow of the Research Corporation for Science Advancement, and a Fellow of the American Physical Society. In 2020 she was awarded the O’Donnell Award in Science of The Academy of Medicine, Engineering and Science of Texas (TAMEST), and was selected as one of “The SN 10: Scientists to Watch” by Science News. She is also one of the recipients of the 2022 New Horizons in Physics Prize “For leadership in laying foundations for electromagnetic observations of sources of gravitational waves, and leadership in extracting rich information from the first observed collision of two neutron stars.”