Events

Developments in device-independent cryptography

Device-independent cryptography connects the foundational topic of Bell inequalities to the operational task of achieving secure cryptography. With significant progress being made in Bell test experiments, various avenues for further developing device-independent cryptography have been opened. I will give an overview of some background and recent developments in the field, as well as some research questions that should be of interest going forward.

Generation and detection of spin-orbit coupled neutron beams

Structured waves and spin-orbit coupled beams have become an indispensable probe in both light and matter-wave optics [1-2], for neutron specifically, showing distinct scattering dynamics for some samples [3-4]. We present a method of generating neutron orbital angular momentum (OAM) states utilizing 3He neutron spin filters along with four specifically oriented triangular coils and magnetic field shielding. These states are verified via their spin-dependent intensity profiles [5]. The period and OAM number of these spin-orbit states can be altered dynamically via the magnetic field strength within the coils and the total number of coils to tailor the neutron beam towards a particular application or specific material [6].

The Office of Research at the University of Waterloo will be hosting a webinar to provide practical information and answer questions related to the new NSERC Alliance funding options that support Canada’s National Quantum Strategy.

Dissipative landau Zener transition in the weak and strong coupling limits

Landau Zener (LZ) transition is a paradigm to describe a wide range of physical phenomenon. Dissipation is inevitable in realistic devices and can affect the LZ transition probabilities. I will describe how we can model the effect of the environment depending on whether it is weakly or strongly coupled to the system. I will also present our experimental results where we found evidence of crossover from weak to strong coupling limit.

Noncommuting charges: Bridging theory to experiment

Noncommuting conserved quantities have recently launched a subfield of quantum thermodynamics. In conventional thermodynamics, a system of interest and an environment exchange quantities—energy, particles, electric charge, etc.—that are globally conserved and are represented by Hermitian operators. These operators were implicitly assumed to commute with each other, until a few years ago. Freeing the operators to fail to commute has enabled many theoretical discoveries—about reference frames, entropy production, resource-theory models, etc. Little work has bridged these results from abstract theory to experimental reality. This work provides a methodology for building this bridge systematically: we present a prescription for constructing Hamiltonians that conserve noncommuting quantities globally while transporting the quantities locally. The Hamiltonians can couple arbitrarily many subsystems together and can be integrable or nonintegrable. Our Hamiltonians may be realized physically with superconducting qudits, with ultracold atoms, and with trapped ions.

On behalf of the IQC-GSA, we invite you to the IQC RAC BBQ. We hope to see everyone on Friday, September 16^th. Please bring your friends, advisors, group members, and batchmates! We are especially happy to welcome new members of IQC and we hope everyone will take this opportunity to interact with other IQC members and visit RAC.

TQT’s Quantum For Health (Q4Health), is open to all at the University of Waterloo, seeking opportunities where quantum can advance health.

On September 19, TQT will host a Q4Health Launch Event in the Mike and Ophelia Lazaridis Quantum-Nano Centre Rm 0101. This event will include descriptions of quantum for health case studies. Following the talks, there will be a meet and greet to assist in team building. Attendees will receive information updates and an opportunity to register and learn more about upcoming Lunch and Learn sessions.

Register by September 16 (for refreshment planning purposes). There will be limited onsite registration at the event.

There's growing awareness of the lack of diversity in science and the presence of barriers to inclusion. What factors lead to disparities in representation? Why should we be motivated to effect change? What can we do to change things? Will our actions really make a difference? 

This presentation will focus on ideas to challenge the status quo – actions to advance equity, diversity, and inclusion (EDI). We will discuss recent research to illustrate and raise awareness of the many EDI challenges in science, then explore various practical ways to take action to advance EDI. These practical actions stem from our recently released "Science is For Everyone" Teaching toolkit, which provides an abundance of ideas to diversify science education and further support recruitment, retention, and advancement of all students. We will touch on the importance of diversifying content and talk about how Indigenous content is being brought into post-secondary science courses. Finally, we will give an overview of other exciting science EDI initiatives across research and academic life.

Young-June Kim: Alpha-RuCl3: a progress report

Abstract: A bond-dependent anisotropic magnetic interaction called the Kitaev interaction can be found in honeycomb lattice materials with strong spin-orbit coupling, which has made a profound impact on quantum magnetism research. In particular, alpha-RuCl3 has been heralded as a realization of the Kitaev quantum spin liquid state, an elusive new state of matter that harbours Majorana fermions. In this talk, I will give a brief overview of the current status of research on alpha-RuCl3 and discuss recent experimental developments and a few surprising findings using ultra-high-quality samples grown in our laboratory. Our samples have minimal stacking faults even at low temperatures, allowing us to determine the low-temperature crystal structure unambiguously. We also found that the magnetic properties are surprisingly sensitive to the inter-layer configuration, giving rise to various magnetic transition temperatures. We also compare low-energy spin-orbit excitations in various Kitaev materials using resonant inelastic x-ray scattering (RIXS). We found that non-local physics is important for describing the spin-orbit excitations in these materials, in contrast to the conventional belief that local Jeff=1/2 physics is sufficient in these compounds.

Yong-Baek Kim: Quantum Spin Liquids and Criticality in Multipolar Materials

Abstract: Multipolar quantum materials possess local moments carrying higher-rank quadrupolar or octupolar moments. These higher-rank multipolar moments arise due to strong spin-orbit coupling and local symmetry of the crystal-electric-field environment. In magnetic insulators, the interaction between multipolar local moments on frustrated lattices may promote novel quantum spin liquids. In heavy fermion systems, the interaction between multipolar local moments and conduction electrons may lead to unusual non-Fermi liquids and quantum criticality. In this talk, we first discuss a novel quantum spin ice state, a three-dimensional quantum spin liquid with emergent gauge field, that may have been realized in Ce₂Zr₂O₇ and Ce₂Sn₂O₇, where Ce³⁺ ions carry dipolar-octupolar moments. We present a theoretical analysis of possible quantum spin ice states in this system and compare the theoretical results of dynamical spin structure factors with recent neutron scattering experiments. Next, we present a theoretical model to describe the unusual Kondo effect and quantum criticality in Ce₃Pd₂₀Si₆, where Ce³⁺ moments carry a plethora of dipolar, quadrupolar, and octupolar moments. We show that two consecutive Kondo-destruction-type phase transitions can occur with the corresponding Fermi surface reconstructions. We compare these results with existing experiments and suggest future ultrasound experiments for the detection of emergent quantum critical behaviors.