All Scheduled Events, Physics | AS

December 4, 2023 Monday 12:30 PM +
726 Broadway, 940, CCPP Seminar
Other Center for Cosmology and Particle Physics Events (ccpp)

CCPP Brown Bag
David Hogg
New York University

Nucleosynthesis and mixing in the Milky Way disk

December 4, 2023 Monday 2:00 PM +
726 Broadway, 940, CCPP Seminar
Other Center for Cosmology and Particle Physics Events (ccpp)

Informal Astro Talk
Jonathan Morag
Ben-Gurion University

Analytic Model of Shock Cooling Emission Fitting In Core-collapse SNe

We model shock-cooling emission in the first hours and days of core-collapse supernovae (SNe). A decade of fitting the observed emission to analytic models has shed light on the properties of the progenitor star, but despite its potential, fitting has also led to some inconsistent results, at times in disagreement with other measurement methods. We provide a frequency-dependent analytic formula for the spectral energy distribution (SED), derived from first principles, and carefully calibrated to multigroup numerical simulations with realistic opacity. We choose a simplified system with few free parameters. We span a large parameter space and show insensitivity to deviations from idealized ‘polytropic’ stellar structure. Recently in a systematic analysis of dozens of SNe, our model was used to show that ~70% of type II SNe are well described by simple shock-cooling, with progenitor radii consistent with observed RSG’s in the field. Apart from being a new scientific claim about the state of the progenitors, this result provides confidence in early-time emission fitting and in our method.

December 5, 2023 Tuesday 2:00 PM +
726 Broadway, 940, CCPP Seminar
Astrophysics and Relativity Seminars (astro)

Luca Comisso
Columbia University

From Turbulence to Reconnection to Particle Acceleration: Connecting the Dots

Plasma turbulence, magnetic reconnection, and particle acceleration underpin and drive a multitude of plasma phenomena across a wide spectrum of environments. It comes as no surprise therefore that they constitute three vibrant research areas at the frontier of modern astrophysics. Originally, these three paradigms were treated as distinct plasma processes. However, with the rapid advances in computing, observations and theory, they are converging towards an interconnected and entangled domain. This ongoing progress holds the potential for solving long-standing problems in several areas of plasma astrophysics ranging from the thermal disequilibration of ions and electrons in collisionless accretion flows to the genesis of the most energetic particles in the Universe. In this talk, using a powerful combination of first-principles plasma kinetic simulations and analytical modeling, I will highlight novel insights arising from my research in plasma self-organization regulated by the mutual interplay of turbulence and magnetic reconnection, and the underlying physical principles that link these processes to the acceleration of particles to high energies.

December 5, 2023 Tuesday 2:00 PM +
726 Broadway, 1067, CQP Seminar
Center for Quantum Phenomena Seminars (cqp)

Nathaniel T. Leitao
Harvard University, Department of Physics

Scalable Spin Spiral Squeezing in the Long-Ranged Heisenberg Model

Generating metrologically-useful entanglement is an essential challenge in quantum dynamics and metrology. In this work, we uncover a mechanism to generate scalable spin squeezing utilizing spatially-inhomogeneous spin spiral initial states as a resource. In particular, we show that quenching spin spirals under long-ranged Heisenberg models generates scalable squeezing that is parametrically controlled by the wavelength of the spiral. We elucidate the mechanism generating the squeezing as originating from the enriched non-abelian symmetry of the Heisenberg model and its anomalous transport properties in long-ranged systems. Experimental implementations in both synthetic and natural spin systems are considered. Particularly for three-dimensional dipolar ensembles in solid state, our work provides a realistic path to achieving entanglement-enhanced sensing in ambient conditions due to the robustness of our scheme to both dipolar averaging and positional disorder.

December 6, 2023 Wednesday 2:00 PM +
726 Broadway, 940, CCPP Seminar
High Energy Physics Seminars (hep)

Carlos Wagner
University of Chicago and Argonne National Laboratory

The Muon g-2 puzzle

The muon anomalous magnetic moment, g-2, has been used as a relevant precision measurement, since it is sensitive to the presence of new particles in a wide range of mass scales. The current g-2 measurement at the Fermilab National Laboratory has an unprecedented level of precision, and can be therefore used to probe the SM g-2 prediction. At the level required to probe the theory, however, one needs to calculate the non-perturbative hadronic corrections accurately. Two different non-perturbative approaches have been used to compute these corrections, one based on electron scattering data and dispersion relations and the other based on lattice gauge theory calculations. These computations give results that disagree with each other at a level that prevents the possibility of probing the presence of new physics. In this talk I will expand on this situation and explain what would be the consequences of assuming that each of the hadronic vacuum polarization computations is correct, and I will also analyze a possible way of reconciling these two discrepant computations.

December 7, 2023 Thursday 11:00 AM +
726 Broadway, Room 1067
Center for Quantum Information Physics Seminars (cqip)

Guo-Yi Zhu
Institute for Theoretical Physics, University of Cologne

Nishimori’s cat in a noisy quantum processor

Traditionally, measurements have been synonymous with extracting information from physical systems. Yet in quantum mechanics, measurements exhibit a Janus-faced character allowing them to also actively modify and steer quantum states, which forges a new route to entanglement generation and a pathway to preparing unconventional quantum states. From a conceptual point of view, it has remained an open question whether these measurement-based state preparation protocols can lead to phases of matter which are stable to gate imperfections. In this talk I will focus on a shallow circuit targeting at the “hydrogen atom” of long-range entangled states - the Greenberger-Horne-Zeilinger "cat state". Analytically, we find that its long-range order is stable against certain coherent and incoherent errors, up to a finite threshold. The threshold is governed by Nishimori physics featuring a conspiracy (fueled by Born’s rule) of disorder and effective temperature. Experimentally, I’ll discuss an implementation of this protocol and a realization of the Nishimori transition on one of IBM's 127-qubit quantum processor. If time permits, I'll briefly show a generalization of this physics to non-commuting measurements and the Floquet honeycomb code, where the frustration of measurements leads to highly entangled quantum liquid.

December 7, 2023 Thursday 4:00 PM +
Hybrid: 726 Broadway, 940 and Zoom
Physics Colloquia (colloquia)

William Jacobs
Princeton University

Rational Design of Multicomponent Biomolecular Condensates

Biology provides numerous examples of phase-separated protein and nucleic acid condensates, which establish distinct compartments for spatially organizing biomolecules within living cells. This mechanism of spatial organization relies on the ability of biomolecular systems to produce complex phase diagrams by tuning the interactions among molecules in a multicomponent mixture. To reproduce this behavior in synthetic systems, it is essential that we identify design rules that map the sequences of individual biomolecules to the emergent phase behavior of multicomponent systems. In this talk, I will describe recent theoretical and computational advances towards the goal of designing fully programmable, synthetic multiphase condensates. These results take the form of scaling relations that bound the complexity of phase diagrams that can be achieved in various biomolecular systems, as well as optimization algorithms for designing biomolecular mixtures that can spontaneously assemble into prescribed multiphase condensates. I will also discuss how nucleation pathways for biomolecular condensate assembly can be rationally designed, providing a mechanism for achieving precise spatiotemporal control of multicomponent, multiphase systems. Taken together, these design rules provide a deeper understanding of the limits of phase-separation-mediated spatial organization in biological systems and establish practical strategies for engineering fully programmable multiphase condensates.

December 12, 2023 Tuesday 2:00 PM +
726 Broadway, 1067, CQP Seminar
Center for Quantum Phenomena Seminars (cqp)

Pouyan Ghaemi
CCNY

Quantum Algorithm to Realize and Study Fractional Hall States and Their Dynamics on Near Term Quantum Computers: A Tabletop Experiment on Quantum Gravity

Intermediate-scale quantum technologies provide unprecedented opportunities for scientific discoveries while posing the challenge of identifying important problems that can take advantage of them through algorithmic innovations. Fractional Hall systems which are one class of correlated electron systems with many interesting and puzzling properties. In this talk I present an efficient quantum algorithm to generate an equivalent many-body state to Laughlin's ν=1/3 fractional quantum Hall state on a digitized quantum computer. Our algorithm only uses quantum gates acting on neighboring qubits in a quasi-one-dimensional setting, and its circuit depth is linear in the number of qubits. I then present another quantum algorithm to generate and study out of equilibrium properties of fractional Hall state. Such features reveals novel geometric aspects of fractional Hall states which mimics gravitons.

December 13, 2023 Wednesday 2:00 PM +
726 Broadway, 940, CCPP Seminar
High Energy Physics Seminars (hep)

LianTao Wang
University of Chicago

TBD

December 14, 2023 Thursday 4:00 PM +
Hybrid: 726 Broadway, 940 and Zoom
Physics Colloquia (colloquia)

Jo Dunkley
Princeton University

Looking for Cracks in the Cosmological Model

Recent observations of the cosmic microwave background are allowing us to scrutinize the ‘Lambda - Cold Dark Matter' cosmological model, and to weigh in on possible cracks in this model that may be appearing from different astronomical observations. I will describe recent results from the Atacama Cosmology Telescope, and show how the relic CMB light can be used as a backlight to weigh cosmic structures and to map out the dark matter over half the sky. I will also describe near-term prospects for an improved view of the physics of the early universe from these new data, and longer term prospects from the upcoming Simons Observatory.

December 15, 2023 Friday 2:00 PM +
726 Broadway, 940, CCPP Seminar
Other Center for Cosmology and Particle Physics Events (ccpp)

Informal HEP Talk
Raphael Bousso
UC Berkeley

December 18, 2023 Monday 11:00 AM +
726 Broadway, Room 1067
Center for Quantum Information Physics Seminars (cqip)

Kungang Li
University of Maryland

Energy relaxation time fluctuations in transmon qubits with different superconducting gaps

Superconducting qubits are an ideal platform for quantum computing and the relaxation time T1 has increased in recent years. We have repeatedly measured the behavior of Al/AlOx/Al transmons that have electrodes with different superconducting gaps in a 3-D cavity and observed significant fluctuations. In our devices, base electrode was formed from nominally pure aluminium while the counter electrode was formed from oxygen-doped aluminium. The measurement of T1 varied from 100 to 300 μs under low temperature and the maximum T1 of the transmon observed was 310 μs at 20 mK. A device with a thin doped-Al base electrode and thick pure Al counter electrode showed T1fluctuations of a similar size with maximum T1 values over 200 μs. Measurements of the fluctuations versus temperature reveal that the standard deviation of T1 is proportional to T1. I proposed a mechanism for exploring the T1 fluctuation data and discuss the possible underlying cause of the T1 fluctuations.

January 9, 2024 Tuesday 2:00 PM +
726 Broadway, 1067, CQP Seminar
Center for Quantum Phenomena Seminars (cqp)

Tzu-Chieh Wei
Stony Brook University

TBA

February 8, 2024 Thursday 11:00 AM +
726 Broadway, Room 1067
Center for Quantum Information Physics Seminars (cqip)

Tina Brower-Thomas
Howard University

How an Interest in π-systems Led to a Career in Quantum and Quantum in three Dimensions

Self-assembled conjugated π-systems, such as aromatic thiols, on gold substrates buoyed the field of molecular electronics and offered a unique solution to some of the challenges faced by the semiconductor industry. Another π-system that holds even a greater promise is graphene, a single atom thick layer of carbon atoms. In fact, the impact of the successful exfoliation of graphene from bulk graphite has left an indelible mark on several fields, including condensed matter physics, chemistry, and materials science. Although graphene possesses some promising properties, such as high mobility and high thermal conductivity, graphene’s lack of a bandgap and magnetic properties has impeded its use in a variety of industrial applications, including electronics and spintronics. My group aims to functionalize graphene, improving graphene’s function without fundamentally affecting its desirable properties. Although theoretical reports of graphene’s interaction with transition metal (TM) and alkali ions (AI) show a retention of graphene’s properties upon the adsorption of these atoms, experimental approaches are needed to substantiate these theoretical works. Motivated by a lack of comprehensive experimental work in this field, we have been investigating the interaction of TM and AI with the surface of graphene using chemical and electrochemical reactions. Finally, I am setting up a microwave plasma chemical vapor deposition system that will be coupled to x-ray diffraction at the Brookhaven National Laboratory Synchrotron Source for in-situ x-ray growth studies of diamond growth. In addition to discussing our work in the field, we will also discuss our contributions in quantum education and work force development.

February 13, 2024 Tuesday 2:00 PM +
726 Broadway, 1067, CQP Seminar
Center for Quantum Phenomena Seminars (cqp)

Brandon Grinkemeyer
Harvard University

TBA

February 22, 2024 Thursday 4:00 PM +
Hybrid: 726 Broadway, 940 and Zoom
Physics Colloquia (colloquia)

Brad Marston
Brown University

Waves of Topological Origin in the Fluid Earth System and Beyond

Symmetries and topology are central to our understanding of physical systems. Topology, for instance, explains the precise quantization of the Hall effect and the protection of surface states in topological insulators against scattering from disorder or bumps. However discrete symmetries and topology have not, until recently, contributed much to our understanding of the fluid dynamics of oceans and atmospheres. In this talk I show that, as a consequence of the rotation of the Earth that breaks time reversal symmetry, equatorial Kelvin and Yanai waves emerge as topologically protected edge modes. The non-trivial topology of the bulk Poincaré waves is revealed through their winding number in frequency - wavevector space. Bulk- interface correspondence then guarantees the existence of the two equatorial waves. I discuss our recent direct detection of the winding number in observations of Earth’s stratosphere. Thus the oceans and atmosphere of Earth naturally share basic physics with topological insulators. As equatorially trapped Kelvin waves in the Pacific ocean are an important component of El Niño Southern Oscillation, the largest climate oscillation on time scales of a few years, topology plays a surprising role in Earth’s climate system. We also predict that waves of topological origin will arise in magnetized plasmas. The waves may appear in laboratory plasma experiments, and they may also arise in the solar system and beyond.

March 14, 2024 Thursday 11:00 AM +
726 Broadway, Room 1067
Center for Quantum Information Physics Seminars (cqip)

Mattias Fitzpatrick
Dartmouth College

Quantum Simulation with Superconducting Circuits: Synthetic Quantum Matter to Non-Hermitian Sensing

In recent years, superconducting circuits have garnered much attention due to their use in quantum computers and quantum annealers. However, this technological platform can also be used to study problems in condensed matter and many-body physics where microwave photons are the particles of interest and interactions are engineered using superconducting qubits or other nonlinearities. In this talk, I will describe my work building hyperbolic superconducting circuit lattices and the associated flat bands that arise in their band structure. From here, I will discuss recent work in my new lab at Dartmouth, where we have developed a means of controlling the effective photon hopping in lattices. Using directional amplification and phase shifters, I will show how to create effectively tunable hopping rates in the Hermitian and non-Hermitian domains. Finally, I will discuss nonlinearities in the gain-dominated regime and their implications for self-oscillation sensors.

March 22, 2024 Friday 12:00 PM +
726 Broadway, 940, CCPP Seminar
Other Center for Cosmology and Particle Physics Events (ccpp)

Informal HEP Talk
Chris Hull
Imperial College, London

A covariant action of self-dual p-form gauge fields

April 9, 2024 Tuesday 2:00 PM +
726 Broadway, 940, CCPP Seminar
Astrophysics and Relativity Seminars (astro)

Matthew McQuinn
University of Washington

Solar System-scale Interferometry on Fast Radio Bursts

April 9, 2024 Tuesday 2:00 PM +
726 Broadway, 1067, Special CQP Seminar
Center for Quantum Phenomena Seminars (cqp)

Yuichi Saito
Lancaster University

TBA

April 16, 2024 Tuesday 2:00 PM +
726 Broadway, 1067, CQP Seminar
Center for Quantum Phenomena Seminars (cqp)

Jiadong Zang
University of New Hampshire

TBA