Seminars

Title: Constant-Time Quantum Search with a Many-Body Quantum System

Thomas Wong, Creighton University

Tuesday, August 26, 2025

2:00-3:00pm,  105 Lin Hall

Abstract: The optimal runtime of a quantum computer searching a database is typically cited as the square root of the number of items in the database, which is famously achieved by Grover's algorithm. With parallel oracles, however, it is possible to search faster than this. We consider a many-body quantum system that naturally effects parallel queries, and we show that its parameters can be tuned to search a database in constant time, assuming a sufficient number of interacting particles. In particular, we consider Bose-Einstein condensates with pairwise and three-body interactions in the mean-field limit, which effectively evolve by a nonlinear Schrödinger equation with cubic and quintic nonlinearities. We solve the unstructured search problem formulated as a continuous-time quantum walk searching the complete graph in constant time. Depending on the number of marked vertices, however, the success probability can peak sharply, necessitating high precision time measurement to observe the system at this peak. Overcoming this, we prove that the relative coefficients of the cubic and quintic terms can be tuned to eliminate the need for high time-measurement precision by widening the peak in success probability or having it plateau. Finally, we derive a lower bound on the number of atoms needed for the many-body system to evolve by the effective nonlinearity.

Title: Quantum Radar with Undetected Photons

Diego Dalvit, Los Alamos National Lab

Friday, September 12th, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Quantum sensing promises to revolutionize sensing applications by employing quantum states of light or matter as sensing probes. Photons are the clear choice as quantum probes for remote sensing because they can travel to and interact with a distant target. Existing schemes are mainly based on the quantum illumination framework, which requires a quantum memory to store a single photon of an initially entangled pair until its twin reflects off a target and returns for final correlation measurements. Existing demonstrations are limited to tabletop experiments, and expanding the sensing range faces various roadblocks, including long-time quantum storage and photon loss and noise when transmitting quantum signals over long distances. We propose a novel quantum sensing framework that addresses these challenges using quantum frequency combs with path identity for remote sensing of signatures (``qCOMBPASS"). The combination of one key quantum phenomenon and two quantum resources, namely quantum induced coherence by path identity, quantum frequency combs, and two-mode squeezed light, allows for quantum remote sensing without requiring a quantum memory. The proposed scheme is akin to a quantum radar based on entangled frequency comb pairs that uses path identity to detect/range/sense a remote target of interest by measuring pulses of one comb in the pair that never flew to target, but that contains target information ``teleported" by quantum-induced coherence from the other comb in the pair that did fly to target but is not detected. This work was recently published in

D.A.R. Dalvit et.al., Quantum Frequency Combs with Path Identity for Quantum Remote Sensing, PRX 14, 041058 (2024).

Title: Atomic Layer Etch for Better Quantum Devices

 Russel Renzas, University of Nevada, Reno 

Tuesday, September 16th,  2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Performance of quantum devices such as superconducting qubits, single photon emitters, and quantum sensors is limited in part by losses at surfaces and interfaces. Conventional fabrication using dry etch processes disorders and contaminates surfaces and sidewalls, increasing device loss. We are developing novel atomic layer etch (ALE) processes with reduced interfacial damage. In this talk, we will describe how quantum devices are made, evidence of interfacial loss, the mechanisms and chemistry of ALE, and how ALE is already being used to improve quantum device performance. 

Title: Searching for Counterexamples to the Goldbach Conjecture Using Cold Atoms

 Maxim Olshanyi, University of Massachusetts 

Tuesday, September 23rd,  2025

2:00-3:00pm,  105 Lin Hall

Abstract:  

In this presentation, we propose three atomic techniques to investigate  the validity of the Goldbach Conjecture, which states that every even integer greater than 2 can be expressed as the sum of two prime numbers. The empirical feasibility of all three approaches is supported by recent experimental progress in creating cold-atomic potentials with a tailored quantum spectrum, achieved in the laboratory of Donatella Cassettari (University of St. Andrews).

First Proposal: We test the contiguity of the set of even numbers generated by all possible sums of two primes, as posited by the Goldbach Conjecture. This set is represented using two atoms in a prime-number potential. If a counterexample to the conjecture exists, a resonant drive will transfer the atomic population from the ground state to a "Goldbach-violation gap" and halt there.

Second Proposal: We construct an analog Grover’s algorithm using two-level atoms in two distinct potentials: one with an even-number spectrum and another with a prime-number spectrum. The drive corresponds to another prime number. This approach yields a quantum advantage, reducing the computational complexity by approximately the square root of the number of even integers tested simultaneously.

Third Proposal: We develop a set of atomtronic band-stop filters using the potentials from the second proposal. These filters remove the population from even-spectrum levels unless no matching prime pair exists. Although this technique involves open quantum systems and lacks quantum coherence, it enables atoms to function as a parallel set of small classical systems.

Title: Correlated Nanoelectronics and Programmable Quantum Matter: Platforms for the Second Quantum Revolution

Jeremy Levy, University of Pittsburgh

Tuesday, October 7th,  2025

2:00-3:00pm,  105 Lin Hall

Abstract:  The second quantum revolution—our growing ability to manipulate quantum states for computation, simulation, and sensing—demands novel approaches to control quantum matter at nanoscale dimensions. In this talk, I will explore how our research at the intersection of correlated nanoelectronics, nanophotonics, and programmable quantum materials forms a unified approach to quantum technologies. Beginning with LaAlO3/SrTiO3 interfaces, I'll demonstrate how nanoscale reconfigurability enables the discovery of exotic quantum phases, including electron pairing outside the superconducting state and degenerate quantum liquids formed from bound states of multiple electrons. This reconfigurability extends to our emerging work with superconducting KTaO3, where we've recently demonstrated nanoscale SQUIDs with remarkable kinetic inductance and gate-tunable properties, and to silicon-based reprogrammable nanoelectronic devices. I'll then discuss how we've expanded this paradigm to van der Waals materials using ultra-low-voltage electron beam lithography to create arbitrary electrostatic patterns unbound by crystal symmetries, establishing a powerful analog quantum simulation platform akin to the quantum gas microscope for cold atoms. Throughout these material systems, we leverage nanophotonic capabilities, including rewritable photodetectors and selective difference frequency generation with over 100 THz bandwidth at nanojunctions, offering unprecedented spatial resolution for THz spectroscopy and optoelectronic functionality. These complementary approaches—spanning complex oxides, silicon, and van der Waals materials—share a common vision: creating quantum systems where electronic, magnetic, and optical properties can be programmed with nanoscale precision, enabling both fundamental insights into quantum matter and practical pathways toward quantum information technologies.

Title: Locating the Dark Exciton in Asymmetrically Strained CdSe/Cd_xZn_1–xSe Quantum Dots and Synthesis of Short-Wave Infrared QD Emitters

 Igor Fedin, University of Alabama

Tuesday, October 14th, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Colloidal CdSe quantum dots (QDs) designed with a high degree of asymmetric internal strain have recently been shown to possess a number of desirable optical properties including sub-thermal room-temperature line widths, suppressed spectral diffusion, and high photoluminescence (PL) quantum yields. It remains an open question whether they are well-suited for applications requiring emission of identical single photons. We find that, in comparison to conventional colloidal CdSe/ZnS core/shell QDs, in asymmetrically strained CdSe QDs, over six times more light is emitted directly by the bright exciton.¹ We attribute this improvement to the two-fold acceleration of the radiative recombination rate and four-fold suppression of the bright-dark relaxation rate in these strained QDs. We locate the emission from the dark exciton in fluorescence line narrowing (FLN) spectra and identify two independent control knobs of bright-dark splitting and acoustic phonon spectra. These results are encouraging for the prospects of chemically synthesized colloidal QDs as emitters of single indistinguishable photons. Armed with this knowledge, we are developing near-IR QDs emitting in the third telecom window (1460 – 1675 nm). By monitoring and manipulating the nucleation and growth rates, we push the emission wavelength to 1.5 μm. We demonstrate acceleration of near-IR emission through efficient surface passivation in colloidal Cd₃P₂ QDs.²

Title: Spatio-temporally Designed Long-Range Quantum Spin Systems

Thomas Bilitewski, Oklahoma State University

Tuesday, October 21st, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Recent years have seen significant improvements in our capability to engineer, control and probe quantum many-body systems at the single particle level and with spatial and temporal resolution. 

These synergistic capabilities define a new frontier for quantum non-equilibrium dynamics with a larger goal of understanding and designing quantum systems and entanglement dynamics for quantum simulation and metrology.

I will talk about recent works in this direction in the context of long-range interacting spin systems, realisable in a range of experimental platforms, from Rydberg arrays over polar or magnetic atoms, NV centers or trapped ions.  Specifically, I'll discuss in detail (i) our latest work connecting the generation of metrologically useful entanglement in the form of spin squeezing to non-equilibrium universality, (ii) how this is enabled by spatio-temporal Floquet control of the interactions in the system ,and time permitting (iii) how it enables the quantum simulation of more exotic phenomena like non-hermitian physics and curved-space times.

References: 

Phys. Rev. Lett. 135, 150401 (2025)

Phys. Rev. A 109, L061304 (2024)

Phys. Rev. Lett. 131, 053001 (2023)

arXiv:2508.17084

Title: Atomic Force Microscopy for Defect Characterization and Strain Control of Two-Dimensional Materials

Matthew Rosenberger, Notre Dame University

Tuesday, October 28th, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  2D materials are exciting materials for future technologies, both in traditional electronics and quantum applications. The properties of 2D materials depend strongly on defects and strain, which presents both a challenge and an opportunity. The challenge is that unwanted defects or random strain variations can degrade material performance. The opportunity is that controlled defects and strain can enable improved performance and new functionalities. In this talk, I will present atomic force microscopy (AFM)-based methods for atomic defect characterization and nanoscale strain control that enable investigations of defect-property and strain-property relationships. In the first part, I will describe our work on developing generalizable approaches for locating, quantifying, and differentiating defects in 2D materials with AFM. In particular, I will show that conductive AFM locates the same defects in transition metal dichalcogenides as scanning tunneling microscopy, providing an efficient method for accurate defect characterization. I will also demonstrate that lateral force microscopy (LFM), a purely mechanical technique, can locate certain types of defects in insulating materials, such as hexagonal boron nitride, and also in semiconducting materials on insulating substrates which is important for growth characterization. In the second part of this talk, I will discuss our work on manipulating the strain distribution within 2D materials. Our approach is to use AFM to indent 2D materials which are placed on top of polymer films. We previously showed that this technique can introduce single photon emitters in monolayer WSe₂. The focus in this talk will be on understanding the limits of nanoindentation for introducing strain. Our work demonstrates a general technique for modifying the strain state of 2D materials in a controllable way, which may allow access to new quantum phenomena in 2D materials.

Title: Scaling optimization with hybrid quantum-classical algorithms

Ilya Safro, University of Delaware

Friday, November 7th, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:   Emerging quantum processors offer new opportunities to explore innovative approaches for solving optimization and machine learning problems in the post-Moore’s law era. However, even with the optimistic expectations regarding building nearly fault-tolerant quantum processors, the limited number of qubits will still make it infeasible to directly tackle massive real-world problems in the near future which reminds the early days of scientific computing and high-performance computing architectures. This presents significant challenges in leveraging these quantum processors for practical applications. Hybrid quantum-classical algorithms, which combine the strengths of both quantum and classical devices, are considered one of the most promising strategies for applying quantum computing to optimization and machine learning problems. In this talk, we will discuss several approaches for designing such algorithms, with a particular focus on multigrid-inspired frameworks for large-scale combinatorial optimization as a flexible paradigm for hybrid quantum-classical algorithms. We will discuss the integration of these frameworks with the Quantum Approximate Optimization Algorithm (QAOA), enhanced with techniques such as graph representation learning, variational parameter transferability, and generative AI, highlighting their potential to improve scalability and quality of quantum approaches.

Relevant papers:

Hayato Ushijima-Mwesigwa, Ruslan Shaydulin, Susan Mniszewski, Christian Negre, Yuri Alexeev, Ilya Safro “Multilevel Combinatorial Optimization Across Quantum Architectures”, ACM Transactions on Quantum Computing, Vol. 2(1), pp. 1-29, 2021, preprint at https://arxiv.org/abs/1910.09985

Ilya Tyagin, Marwa Farag, Kyle Sherbert, Karunya Shirali, Yuri Alexeev, Ilya Safro "QAOA-GPT: Efficient Generation of Adaptive and Regular Quantum Approximate Optimization Algorithm Circuits", IEEE Quantum Computing and Engineering (QCE), preprint at https://arxiv.org/abs/2504.16350, 2025

Jose Falla, Quinn Langfitt, Yuri Alexeev, Ilya Safro “Graph Representation Learning for Parameter Transferability in Quantum Approximate Optimization Algorithm”, Quantum Machine Intelligence, vol. 6, num. 46, preprint at https://arxiv.org/abs/2401.06655, https://doi.org/10.1007/s42484-024-00178-9, 2024

Bao Bach, Jose Falla, Ilya Safro “MLQAOA: Graph Learning Accelerated Hybrid Quantum-Classical Multilevel QAOA”, IEEE Quantum Computing and Engineering, preprint at https://arxiv.org/pdf/2404.14399, 2024

Alexey Galda, Eesh Gupta, Jose Falla, Xiaoyuan Liu, Danylo Lykov, Yuri Alexeev, Ilya Safro “Similarity-Based Parameter Transferability in the Quantum Approximate Optimization Algorithm”, Frontiers in Quantum Science and Technology (section Quantum Information Theory), DOI: 10.3389/frqst.2023.1200975, 2023

Original QAOA paper: Farhi, Edward, Jeffrey Goldstone, and Sam Gutmann. “A quantum approximate optimization algorithm.” arXiv preprint arXiv:1411.4028 (2014).

Classical computing background: Dorit Ron, Ilya Safro, Achi Brandt “Relaxation-based coarsening and multiscale graph organization”, SIAM Multiscale Modeling and Simulations, Vol. 9, No. 1, pp. 407-423, 2011, https://www.eecis.udel.edu/~isafro/papers/relax-coarsening-graphs.pdf

Title: Photonic Integrated Circuits on Thin-Film Lithium Niobate for Electro-optics, Nonlinear and Quantum Optics Applications   

Sasan Fathpour, University of Central Florida

Friday, November 14th, 2025

2:00-3:00pm,  105 Lin Hall

Abstract: Lithium niobate has long been a leading photonic material for optical modulators and wavelength converters, thanks to its strong electro-optic (EO) and nonlinear optical properties. Conventional optical waveguides in bulk lithium niobate, however, suffer from low index contrast, resulting in large device footprints and high-power requirements for efficient EO and nonlinear operation. The development of thin-film lithium niobate (TFLN) wafers with high-contrast, submicron cross-section waveguides has enabled a leap forward in compact photonic circuit design. These device s— such as waveguides, microring resonators, modulators, grating couplers, wavelength converters — achieve performance far superior to traditional bulk lithium niobate counterparts. Among these, key advances include modulators with subterahertz modulation bandwidths, while maintaining low loss, and low-harmonic generation (third, fourth) into visible/UV with high efficiency. With ongoing improvements in efficiency, bandwidth, reliability, and scalability, TFLN is increasingly seen as a frontrunner for integrated quantum photonics. Specifically, generation of high-brightness and spectrally pure quantum-correlated and entangled photons through spontaneous parametric down-conversion, as well as demonstrations of squeezed-light sources, are discussed.  

Title: Reimagining two-channel Kondo physics: fermions to bosons and back in a consistent way   

 Nayana Shah, Washington University, St. Louis

Tuesday, November 25th,  2025:

2:00-3:00pm,  105 Lin Hall

Abstract: The two-channel Kondo model has been a theoretical and experimental playground to understand and probe intermediate coupling fixed points with non-Fermi liquid behavior. We revisit the compactification procedure of the (multi) two-channel Kondo model that rewrites it more “compactly” using the single-channel version of the model by exploiting spin-charge separation. We show that bosonization-debosonization (BdB) can be used as a systematic method for that purpose but only if we use a consistent BdB framework [1,2,3]. In doing so, we also advance the consistent framework [4,5] and further establish why it is so essential to be cognizant of the pitfalls of the conventional BdB framework. Extensive comparisons are carried out in exact limits [1] as well as by using poor man's scaling [2] and field-theoretic renormalization group methods [3]; on the way furthering the latter as well. 

[1] A. Ljepoja, C.J. Bolech, Nayana Shah, Phys. Rev. B 110, 045108 (2024)[2] A. Ljepoja, N. Shah, C.J. Bolech, Phys. Rev. B 110, 045109 (2024)

[3] A. Ljepoja, C.J. Bolech, N. Shah, Phys. Rev. B 110, 045110 (2024)

[4] N. Shah and C.J. Bolech, Phys. Rev. B 93, 085440 (2016)

[5] C.J. Bolech and N. Shah, Phys. Rev. B 93, 085441 (2016)

Title:  90 days in the life of Cloud Quantum Computing

Gino Serpa, Applied Research Laboratory for Intelligence and Security

Friday, December 5th,  2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Quantum Computing (QC) has evolved from a few custom quantum computers, which were only accessible to their creators, to an array of commercial quantum computers that can be accessed on the cloud by anyone. Accessing these cloud quantum computers requires a complex chain of tools that facilitate connecting, programming, simulating algorithms, estimating resources, submitting quantum computing jobs, retrieving results, and more. Some steps in the chain are hardware dependent and subject to change as both hardware and software tools, such as available gate sets and optimizing compilers, evolve.

Understanding the trade-offs inherent in this process is essential for evaluating the power and utility of quantum computers. ARLIS has been systematically investigating these environments to understand these complexities. The work presented here is a detailed summary of three months of using such quantum programming environments. We show metadata obtained from these environments, including the connection metrics to the different services, the execution of algorithms, the testing of the effects of varying the number of qubits, comparisons to simulations, execution times, and cost. Our objective is to provide concrete data and insights for those who are exploring the potential of  quantum computing. It is not our objective to present any new algorithms or optimize performance on  any particular machine or cloud platform; rather, this work is focused on  providing a consistent view of a single algorithm executed using out-of-the-box settings and tools across machines, cloud platforms, and time. We present insights only available from these carefully curated data.

Title: Molecular Neuromorphic Building Blocks for Artificial Intelligence   

Sreetosh Goswami, Indian institute of Science 

Tuesday, December 9th,  2025:

2:00-3:00pm,  105 Lin Hall

Abstract: Artificial Intelligence (AI) has long been a subject of fascination, oscillating between grand promises and inevitable disillusionment. While remarkable milestones, like AI outperforming human champions in complex games, suggest we are entering a new era of computing, a deeper look reveals that these breakthroughs come at a steep cost — demanding vast amounts of energy and intensive, expensive training process. In areas like cognition, decision-making, and intelligence, even our most advanced computing machines fall far short of the brain’s unparalleled efficiency and compact design. The core of this challenge lies in the limitations of conventional circuit elements and computing architectures, which struggle to replicate the brain’s complex, nonlinear dynamics operating at the edge of chaos. In this seminar, I will introduce a new class of molecular circuit elements designed to capture the intricate, reconfigurable logic that mimics brain-like behaviour at the nanoscale. These devices can be operated as analog or digital elements, or could be poised on the verge of instability, offering a unique potential to emulate neural functions in ways that traditional computing hardware cannot. Our journey explores these molecular systems from their foundational physics and chemistry, all the way to integrated circuit design and on-chip applications [1-8] with the aim of laying the groundwork for AI and machine learning platforms that can transcend the limitations of Moore's Law and lead to a new era of energy-efficient computing.

References:

[1] S, H., Bhat, N. & Goswami, S. Neuromorphic pathways for transforming AI hardware. Nat Electron 8, 752–756 (2025). https://doi.org/10.1038/s41928-025-01432-z

[2] Sharma, D., Rath, S.P., Kundu, B., Korkmaz, A., Thompson, D., Bhat, N., Goswami, S., Williams, R.S. and Goswami, S. Linear symmetric self-selecting 14-bit kinetic molecular memristors. Nature 633, 560–566 (2024). 

[3] Sreebrata Goswami, Williams, R. Stanley, and Sreetosh Goswami. "Potential and challenges of computing with molecular materials." Nature Materials (2024): 1-11.

[4] Rath, S. P., Deepak, Goswami, S., Williams, R. S., & Goswami, S. Energy and Space Efficient Parallel Adder Using Molecular Memristors. Advanced Materials (2023), 2206128.

[5] Rath, Santi Prasad, Thompson, Damien, Goswami, Sreebrata, & Goswami, Sreetosh. "Many‐body molecular interactions in a memristor." Advanced Materials (2023): 2204551.

[6] Goswami, Sreetosh, et al. "Decision trees within a molecular memristor." Nature 597.7874 (2021): 51-56.

[7] Goswami, Sreetosh, et al. "Robust resistive memory devices using solution-processable metal-coordinated azo aromatics." Nature Materials 16.12 (2017): 1216-1224.

[8] Goswami, Sreetosh, et al. "Charge disproportionate molecular redox for discrete memristive and memcapacitive switching." Nature Nanotechnology 15.5 (2020): 380-389.

Title: Nano-optics at the extreme

Artur Davoyan, University of California, Los Angeles

Friday, February 21, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Nanoscale structures offer an unprecedented potential f or shaping optical fields at the fraction of a wavelength and for enhancing light-materials interaction. As light gets confined to nanometer dimensions strong enhancement of optical fields allows accessing novel regimes of light-matter interaction. In this talk I will present two manifestations of nanostructure-mediated light-materials interaction. First, I will show that layered van der Waals materials exhibiting strong material resonances allow for extreme confinement of light at the nanoscale, enabling ultra-small-footprint photonic structures and boosting second order nonlinear light generation. Second, I will show that nanostructures provide allow new ways of controlling lasers of extreme intensity. I will demonstrate that plasmonic nanostructures are ideally suited for creating structured solid-density plasmas to tame ultra-high intensity femtosecond beams. For high energy nanosecond pulses light-materials interaction is even more complex and involves materials heating and phase transitions. In particular, I will show that resonant nanostructures allow controlling time-resolved dynamics of photo-thermal interaction, as well as controlling phase transitions.
 

Title: Taming quantum chaos with measurements and feedback

Thomas Iadecola, Iowa State University

Friday, February 28, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Generic isolated quantum systems rapidly lose memory of their initial conditions as they evolve in time. It is a problem of both fundamental and practical interest to devise mechanisms to avert this quantum chaos. Taking inspiration from quantum error correction, we ask whether chaos can be suppressed by an external observer capable of measuring the quantum system and performing feedback operations conditioned on the measurement outcomes. Fortuitously, a classical version of this problem was solved three decades ago with an approach dubbed "probabilistic control of chaos." Probabilistic control randomly intervenes in the chaotic dynamics and attempts to steer the system onto a desired dynamical trajectory with measurement and feedback. As a function of how often the control is applied, a transition occurs between a chaotic phase and a controlled phase where the target trajectory is a global attractor. We generalize this approach to the quantum many-body setting and find that, in addition to the control transition that appears classically, a new entanglement phase transition appears. We discuss the interplay of the two transitions and comment on the possible implications for near-term quantum computers.
 

Title: Quantum Melting of Spin 'Solids' in Two Dimensions

Andriy Nevidomskyy, Rice University  

Tuesday March 4, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  For several decades, the attention of both theoretical and experimental physicists has focused on finding examples of quantum spin liquids — exotic phases of matter characterized by the spin fractionalization, whereby the energy and momentum are carried not by spin waves, but by emergent elementary excitations. By contrast, defining a quantum spin ‘solid’ as a state that spontaneously breaks the lattice translation symmetry, I shall pose the following question — how do quantum solids ‘melt’ and how does entanglement establish itself in a quantum spin liquids ? To answer this question, I shall present our recent work on several 2D systems, from the familiar spin-1/2 on frustrated lattices, to the perhaps less familiar models of spin-1 and SU(3) objects. We study these models using the density matrix renormalization group (DMRG) and infinite projected entangled-pair states (iPEPS) techniques, supplemented by the analytical mean-field and linear flavor wave theory calculations. I shall also discuss another mechanism of quantum ‘melting’, induced by a strong magnetic field — the conventional picture is that this process can be understood as a Bose-Einstein condensation of the auxiliary bosons. Here we show that a more exotic, non-BEC transition occurs when magnetic frustration drives the system across the Lifshitz point, and we find an exotic bosonic liquid that avoids the BEC altogether — so-called Bose metal with algebraic correlations.
 

Title: Transport in Kicked Quantum Matter

Subhadeep Gupta, University of Washington  

Friday, March  14, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Understanding the interplay of interactions and disorder in quantum transport poses long-standing fundamental challenges for both theory and experiment. We have utilized a synthetic momentum lattice platform using ultracold quantum gases kicked by pulsed optical lattices, to investigate this problem. Using periodic as well as quasi-periodic kick protocols, we have experimentally simulated the Anderson transport model in 1D and 3D and observed the interaction-driven emergence of dynamical delocalization, many-body quantum chaos, and shift of the metal-insulator transition [1, 2]. The observed dynamics feature sub-diffusive energy growth and sheds light on the evolution of dynamically localized states in the presence of many-body interactions, which has long remained an open question. The kicking protocol can also open new opportunities for investigating pairing in strongly interacting fermionic systems. Our results shed light on interaction-driven transport phenomena in quantum many-body systems, in a regime where theoretical approaches are extremely challenging.

[1] J. See Toh et al., Nature Physics 18, 1297 (2022).

[2] J. See Toh et al., Phys. Rev. Lett. 133, 076301 (2024).

Title: "Epsilon near zero materials - so what?"

Nathaniel Kinsey, Virginia Commonwealth University  

Friday, April 11, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  The epsilon-near-zero regime has received attention in the last decade for enabling unique optical phenomena and enhancing interactions. Among them, the ability to improve nonlinear optical interactions has been one of the most praised features. In this talk i will summarize the work of my team to measure, model and analyze nonlinear interactions in the epsilon-near-zero regime, focusing primarily on permittivity modulation. We will critically examine what features ENZ actually provides to improve nonlinear interactions and why, as well as explore avenues to push its strengths. Finally, we will conclude with some examples where my team has explored potential use cases for nonlinear refraction in ENZ such as frequency control and ultrafast pulse measurement.
 

Title: Quantum Abacus: Anyons in One Dimension

Nathan Harshman, American University  

Friday, April 11, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Recent experimental advances with ultracold atoms in one-dimensional optical traps allows exploration of non-standard particle statistics. In this talk, I use the possibility of a quantum abacus to explain and explore the ideas of topological quantum computing with anyons in one dimension. Most proposals for topological quantum computers rely on the properties of braiding anyons in two dimensions. But is it possible to make a topological quantum computer in one dimension? Are anyons even possible in one dimension? The answer, recently confirmed by experiments, is yes: topological exchange statistics are possible in one dimension.
 

Title: Developing two-dimensional materials for quantum technologies

Nicholas Borys, Montana State University 

Friday, April 25, 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  ability to engineer materials at the levels of single atomic layers. Material systems based on 2D materials have been exploited to realize new states of matter, and many are appealing for applications, spanning from modern electronics to the development of new quantum technologies. At the atomic level, the unifying characteristic of these materials is their layered structure that enables individual sheets of atoms to be mechanically peeled – or exfoliated – from a bulk crystal and isolated in a true 2D form. Depending on the material, the resulting atomic sheets can be metals, semiconductors, ferromagnets, superconductors, etc. These layers can be further picked up and transferred onto one another, providing seemingly endless opportunities for layer-by-layer assembly of sophisticated 2D heterostructures with distinct physical properties. 

A major challenge to capitalizing on the unprecedented versatility of 2D materials is that assembling such 2D heterostructures is typically performed manually, making the process painstakingly tedious and plagued with low yields. I will overview our efforts within the MonArk NSF Quantum Foundry to develop robotic instrumentation to overcome these challenges and demonstrate how automation advancements from the semiconductor industry along with artificial intelligence can expedite 2D quantum materials research. In addition, I will highlight our work to develop on-demand single-photon light sources based on 2D semiconductors for quantum photonic technologies. These studies include the exploration of new architectures and the use of nano-optical techniques to unravel the interplay between strain, electronic structure, and excited state dynamics in the quantum light emission processes. The research efforts here contribute to the development of 2D semiconductors for integrated quantum photonics and illustrate how the right fabrication and characterization tools can accelerate the pace of exploration of the technological and scientific opportunities presented by 2D materials.

Title: Diamond: The most versatile ultra wide bandgap quantum material for many applications

MS Ramachandra Rao,  Indian Institute of Technology (IIT) Madras, Chennai

Friday, June 13th , 2025

2:00-3:00pm,  105 Lin Hall

Abstract:  Our group focusses on the physics, doping and electronic correlations, defect-engineering and applications of thin films and nano-structures of TMOs and diamond. During the past two decades, we have been focusing on utilizing diamond, the most versatile ultra-wide bandgap material for many technological applications. Diamond is a fascinating allotrope of carbon that offers half a dozen different applications and its lattice is amenable to doping. Diamond, despite being one of the most resistive materials, is driven to a semiconducting to superconducting state by boron doping and boron doped diamond (BDD) is considered as the most useful next generation granular superconductor useful for quantum-interface devices requiring high kinetic inductance. We have also demonstrated the use of boron doped diamond electrodes in the waste-water treatment. We are focusing on the quantum applications of diamond using nitrogen and other dopants. I will give a summary of our research and development journey of diamond.