On Wednesday, May 18, 2022 the Institute for Quantum Computing will host the Toronto Ultracold Atom Network (TUCAN).
The one-day meeting aims to both share knowledge and strengthen ties between local ultracold atom groups. The day will consist of talks and posters on topics including trapped ions, optical lattices, Bose-Einstein condensates and optical techniques for atomic state manipulation.
Organizers: Ali Binai-Motlagh and Rajibul Islam from the Institute for Quantum Computing (IQC).
TUCAN will be hosted in the Mike & Ophelia Lazaridis Quantum-Nano Centre (QNC) Room 0101
Schedule and abstracts
Mike & Ophelia Lazaridis Quantum-Nano Centre (QNC) Room 0101
| Time | Event | Title | Speaker | Group |
|---|---|---|---|---|
| 9:30 am | Coffee and refreshments | |||
| 10:00 am | Talk 1 |
How much time does a photon spend as an atomic excitation before being transmitted? |
Kyle Thompson | Aephraim Steinberg |
| 10:20 am | Talk 2 | A waveguide-based Individual addressing system for optical addressing of Barium ions | Ali Binai-Motlagh |
Kazi Rajibul Islam |
| 10:40 am | Talk 3 |
Macroscopic quantum self-trapping and catastrophes in a rotating Bose-Einstein condensate |
Denise Kamp |
Duncan O. Dell |
| 11:00 am | Break/Discussion | |||
| 11:20 am | Talk 4 | Unitary fermionic p-wave interactions in an optical lattice | Vijin Venu | Joseph Thywisse |
| 12:00 pm | Talk 5 | Molecules trapped in neon ice | Samuel Li |
Amar Vutha |
| 12:20 pm | Talk 6 |
Trapped Ion Qudit Quantum Computing: Functionalities with Barium’s Metastable D-5/2 States |
Pei Jiang Low | Crystal Senko |
| 12:40 pm | Lunch/Discussion | |||
| 1:40 pm | Talk 7 | Reversible tuning of nanowire quantum dot to atomic transition | Rubayet Al Maruf | Michal Bajcsy |
| 2:00 pm | Talk 8 | Zack Hinkle |
Alan Jamison |
|
| 2:20 pm | Talk 9 | Luca Dellantonio | Christine Muschik | |
| 2:40 pm | Break/Lab Tours | |||
| 4:00 pm | Closing remarks |
Abstracts
How much time does a photon spend as an atomic excitation before being transmitted?
Kyle Thompson
When a resonant photon traverses a cloud of 2-level atoms, how much time does it spend as an atomic excitation? Does the answer depend on whether the photon is ultimately absorbed or transmitted? In particular, if it is not absorbed, does it cause atoms to spend any time in the excited state at all? Our recent experiment using single-photon-level optical nonlinearities [PRX Quantum 3, 010314] suggests that it does. In this talk, I will describe a recently-developed theoretical approach to this problem using the weak-value formalism, and the counter-intuitive predictions it makes for the time that transmitted photons spend as atomic excitations. The corresponding time for scattered photons will also be discussed. This work provides insight into the complex histories of photons travelling through absorptive media.
A waveguide-based Individual addressing system for optical addressing of Barium ions.
Ali Binai-Motlagh
With their long coherence times and high-fidelity gates, trapped atomic ions are one of the leading platforms for realizing quantum information processing in the NISQ era and beyond. For universal quantum computation, control over the state of individual and pairs of qubits is necessary. Current systems for individual ion addressing either have poor crosstalk properties, lack parallel addressability, or lack the ability to independently control the frequency and phase of each channel. This talk will present the unique individual addressing system being developed for our Barium ion trap computer that addresses these challenges. The system consists of a laser-written waveguide chip that splits light into multiple channels, one for each ion in the trap, and couples that light to an array of single mode fibers. Fiber based acousto-optic modulators then provide control over the frequency and amplitude of each beam which is necessary for the implementation of entangling gates. Finally, an imaging system consisting of an array of micro-lenses maps the light from each fiber channel to an ion in the trap with minimal crosstalk. The use of such waveguiding technology is enabled by the desirable energy level structure of the Barium ion where most transition lie in the visible range of the spectrum.
Macroscopic quantum self-trapping and catastrophes in a rotating Bose-Einstein condensate
Denise Kamp
We consider a dilute gas of bosons in a slowly rotating toroidal trap, focusing on the two-mode regime consisting of a stationary mode and a rotating mode corresponding to a single vortex. This system undergoes a symmetry breaking transition as the ratio of interactions to `disorder potential’ is varied and chooses one of the two modes spontaneously, an example of macroscopic quantum self-trapping. A sudden quench in the system can be treated within the truncated Wigner approximation and displays cusp-shaped structures in the number and phase distributions that correspond to quantum versions of elementary catastrophes.
Unitary fermionic p-wave interactions in an optical lattice
Vijin Venu
Resonantly enhanced and controllable p-wave interactions in ultracold atomic systems are a promising test bed for realizing unconventional superconductors and superfluids with non-trivial transport properties. However, p-wave and other antisymmetric interactions are weak in naturally occurring systems, and their enhancement via Feshbach resonances in ultracold systems has been limited by three-body loss. We report on spectroscopic measurements of Feshbach-enhanced p-wave interactions of 40K, where three-body loss is suppressed by loading spin polarized atoms in a multi-band 3D optical lattice. Our measurements show excellent agreement to an exact solution for two harmonically confined atoms interacting via a p-wave pseudopotential, and to numerical solutions using an ab-initio interaction potential. We also demonstrate the coherence of the conversion process between non-interacting and strongly interacting atomic pairs by measuring Rabi oscillations between them with a frequency consistent with theory. Finally, we demonstrate that losses in p-wave interacting pairs are limited by the intrinsic lifetime of the free-space molecular dimer, and we observe lifetimes that are fifty times larger than previous measurements in 40K. These pioneering experiments test theoretical predictions of two-body p-wave interactions and open doors towards realizing novel many-body states with them.
Molecules trapped in neon ice
Samuel Li
Searches for electric dipole moments (EDMs) of fundamental particles offer a way to probe ultra-high-energy physics using lab-scale precision measurements. The search for the electron EDM requires large numbers of polar molecules whose spin precession can be measured for an extended duration. To circumvent the challenges and limitations of
current approaches that use laser-cooled molecules, we are developing an approach that instead uses polar molecules trapped in ice films. We will present our progress and discuss the path ahead.
Trapped Ion Qudit Quantum Computing: Functionalities with Barium’s Metastable D-5/2 States
Pei Jiang Low
The metastable D-5/2 states of barium ions present several functionalities that are useful for qudit quantum computing. Using the S-1/2 to D-5/2 quadrupole transition of a barium ion, the metastable D-5/2 states can be utilized as shelved states, for cooling the ions or as computational states. We present our recent progress with experimental manipulation of these states. They include spectroscopy of the D-5/2 states, cooling performance achieved in our lab and state preparation and measurement (SPAM) of a multi-level qudit system.
Reversible tuning of nanowire quantum dot to atomic transition
Rubayet Al Maruf
We describe a new method for reversible and bi-directional in-situ precision tuning of the wavelength of single photons emitted by a nanowire quantum dot, using the deposition of inert gas. This method, which can be reversed by increasing the temperature or using focused laser to evaporate the deposited gas, has allowed us to match the D1 transition (∼895 nm) of cesium atom. We report the emitted photon characteristics including second-order correlation function g(2)(τ) and linewidth, as well as the lifetime of the quantum dot before and after the wavelength tuning. We also discuss our initial experiments studying interactions between the single photons and atomic ensembles.
A novel ultra-high vacuum atomic beam oven design
Zack Hinkle
Traditional alkali atomic beam ovens in ultra-high vacuum (UHV) typically entail heating the chamber exterior to 100s of degrees Celsius. This is undesirable, because such high temperatures will produce air currents, negatively affecting optics near the chamber. In this talk a new oven design is discussed that allows interior temperatures of 500°C to be achieved while the exterior remains below 50°C with relatively low power requirements (below 100W). Preliminary results on using CsCl + Ca to produce a Cs beam will also be shown.
The measurement based variational eigensolver
Luca Dellantonio
Variational quantum eigensolvers (VQEs) combine classical optimization with efficient cost function evaluations on quantum computers. We propose a new approach to VQEs using the principles of measurement-based quantum computation. This strategy uses entangled resource states and local measurements. We present two measurement-based VQE schemes. The first introduces a new approach for constructing variational families. The second provides a translation of circuit- based to measurement-based schemes. Both schemes offer problem specific advantages in terms of the required resources and coherence times.
Code of conduct
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