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Events During the Week of February 5th through February 12th, 2023

Monday, February 6th, 2023

Atomic Physics Seminar
Beyond quantum circuits with trapped-ion qubits
Time: 11:00 am
Place: 5310 Chamberlin Hall
Speaker: Or Katz, Duke University
Abstract: Trapped ions are a leading quantum technology for quantum computation and simulation, with the capability to solve computationally hard problems and deepen our understanding of complex quantum systems. The quantum circuit model is the central paradigm for quantum computation, enabling the realization of various quantum algorithms by application of multiple one- and two-qubit entangling operations. However, the typical number of entangling operations required by this model increases exponentially with the number of qubits, making it difficult to apply to many problems.
In my presentation, I will discuss new methods for realizing quantum gates and simulations that go beyond the quantum circuit model. I will first describe a single-step protocol for generating native, N-body interactions between trapped-ion spins, using spin-dependent squeezing. Next, I will present a preparation of novel phases of matter using simultaneous and reconfigurable spin-spin interactions. Lastly, I will explore new avenues to harness the long-lived phonon modes in trapped-ion crystals for simulating complex bosonic and spin-boson models that are difficult to solve using classical methods. The presented techniques could push the performance of trapped-ion systems to solve problems that are currently beyond their reach.
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Tuesday, February 7th, 2023

R. G. Herb Condensed Matter Seminar
TBD
Time: 10:10 am
Place: 5310 Chamberlin
Speaker: Daniel Parker , Harvard
Host: Victor Brar
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Wednesday, February 8th, 2023

Preliminary Exam
Searches for transient astrophysical neutrino sources with IceCube
Time: 10:00 am
Place: 4274 Chamberlin
Speaker: Jessie Thwaites, Physics Graduate Student
Abstract: Multi-messenger astrophysics is a powerful tool for understanding the most energetic sources in the universe. Although IceCube has discovered a flux of extragalactic neutrinos, the sources of the vast majority of those neutrinos remain a mystery. We describe searches for neutrino emission from transient astrophysical source classes, both in archival searches and real-time analyses. In archival data, we use IceCube-DeepCore to search for GeV neutrinos from novae, and set the first upper limits on neutrinos from novae. We describe a planned search for neutrinos from fast radio bursts (FRBs) using the first catalog published by the CHIME/FRB Collaboration, which provides more than an order of magnitude more sources than previous IceCube FRB searches. We also describe real-time follow-up searches for neutrinos from astrophysical transients, including for the brightest gamma-ray burst ever recorded, GRB 221009A, for which we report a non-detection and set strong constraints on neutrino emission. We also describe planned follow-ups of gravitational wave events during LIGO-Virgo-KAGRA operating run 4, which is anticipated to start providing alerts as early as mid-February 2023.
Host: Justin Vandenbroucke
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Physics ∩ ML Seminar
Bayesian Updating and dynamical flows
Time: 11:00 am
Place: Online Seminar: Please sign up for our mailing list at www.physicsmeetsml.org for zoom link
Speaker: David Berman, Queen Mary University
Abstract: Statistical Inference is the process of determining a probability distribution over the space of parameters of a model given a data set. As more data becomes available this probability distribution becomes updated via the application of Bayes’ theorem. We present a treatment of this Bayesian updating process as a continuous dynamical system. Statistical inference is then governed by a first order differential equation describing a trajectory or flow in the information geometry determined by a parametric family of models. We solve this equation for some simple models and show that when the Cram´er-Rao bound is saturated the learning rate is governed by a simple 1/T power-law, with T a time-like variable denoting the quantity of data. We illustrate this with both analytic and numerical examples based on Gaussians and the inference of the coupling constant in the Ising model. Finally we compare the qualitative behaviour exhibited by Bayesian flows to the training of various neural networks on benchmarked data sets such as MNIST and CIFAR10 and show how that for networks exhibiting small final losses the simple power-law is also satisfied.
Host: Gary Shiu
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Atomic Physics Seminar
Quantum many-body physics with ultracold molecules
Time: 11:00 am
Place: 5310 Chamberlin Hall
Speaker: Zoe Yan , Princeton University
Abstract: A central challenge of modern physics is understanding the behavior of strongly correlated matter. Current knowledge of such systems is limited on multiple fronts: experimentally, these materials are often difficult to fabricate in laboratory settings, and numerical simulations become intractable as the number of particles approaches meaningful values. In the spirit of Feynman, physicists can model diverse phenomena, from high-temperature superconductivity to quantum spin liquids, using analog quantum simulation. My research explores emergent quantum phenomena in pristine systems made of atoms, molecules, and electromagnetic fields. In particular, ultracold molecules are a promising platform due to their tunable long-range interactions and large set of internal states. However, this nascent platform requires new experimental techniques to create, control, and probe molecular systems.
I will report on efforts to create ultracold polar molecules, coherently manipulate their internal levels, and demonstrate second-scale coherence times in a molecular ensemble. To leverage the long-range, anisotropic dipolar interactions, we engineer dipolar collisions in a bulk ensemble using the technique of microwave dressing. Upon loading polar molecules into a 2D optical lattice, we study dynamics and thermalization in a variety of spin models relevant to quantum magnetism. Toward that end, we develop a novel readout modality – quantum gas microscopy – to perform site-resolved fluorescence imaging, enabling the measurement of quantum correlations and entanglement. The techniques presented here establish ultracold molecules as a compelling platform for quantum science and technology.
Host: Thad Walker
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Theory Seminar (High Energy/Cosmology)
Title to be announced
Time: 1:00 pm
Place: Chamberlin 5280
Host: George Wojcik
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Thursday, February 9th, 2023

R. G. Herb Condensed Matter Seminar
TBD
Time: 10:00 am
Place: 5310 Chamberlin
Speaker: Zhu-Xi Luo, Harvard
Host: Victor Brar
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Condensed Matter Theory Group Seminar
Constructive approaches to frustrated magnetism: Moiré and Measurements
Time: 10:00 am
Place: 5310 Chamberlin Hall
Speaker: Zhu-xi Lou , Harvard University
Abstract: Frustrated magnetism arises when spins interact through competing exchange interactions which cannot be simultaneously satisfied. When the frustrations are strong enough, exotic states can emerge such as long-range entangled spin liquids. Unfortunately, solid state materials are complicated and frustrations are hard to control: To this date, quantum spin liquids are still challenging to be realized in experiments. Naturally, researchers seek more manageable experimental systems, in the hope of engineering frustrated magnetism constructively. I will discuss my recent works in two types of such manageable systems: moire heterostructures in van der Waals materials where many tuning knobs are available; and monitored quantum circuits where designer gates and measurements are exploited as new sources of frustrations.
Host: Victor Barr
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NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Hunting EeV Neutrinos with RNO-G and PUEO
Time: 2:30 pm
Place: Chamberlin 4274
Speaker: Cosmin Deaconu, University of Chicago
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Friday, February 10th, 2023

Physics Department Colloquium
TBD
Time: 3:30 pm
Place: Chamberlin 2241
Speaker: Micheline Soley , UW Madison - Department of Chemisty
Host: Baha Balantekin, Bob Joynt
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Saturday, February 11th, 2023

Wonders of Physics
The Wonders of Physics 40th annual show
Time: 1:00 pm
Place: 2103 Chamberlin
Abstract: The Wonders of Physics annual show is a fast-paced, engaging, and educational physics program, filled with demonstrations that help people better understand the physics in the world around them, while having fun at the same time.
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Wonders of Physics
The Wonders of Physics 40th annual show
Time: 4:00 pm
Place: 2103 Chamberlin
Abstract: The Wonders of Physics annual show is a fast-paced, engaging, and educational physics program, filled with demonstrations that help people better understand the physics in the world around them, while having fun at the same time.
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Sunday, February 12th, 2023

Wonders of Physics
The Wonders of Physics 40th annual show
Time: 1:00 pm
Place: 2103 Chamberlin
Abstract: The Wonders of Physics annual show is a fast-paced, engaging, and educational physics program, filled with demonstrations that help people better understand the physics in the world around them, while having fun at the same time.
Add this event to your calendar
Wonders of Physics
The Wonders of Physics 40th annual show
Time: 4:00 pm
Place: 2103 Chamberlin
Abstract: The Wonders of Physics annual show is a fast-paced, engaging, and educational physics program, filled with demonstrations that help people better understand the physics in the world around them, while having fun at the same time.
Add this event to your calendar