CQT Anniversary
CQT's Anniversary Events

Join us for a symposium commemorating twelve years of CQT

12th Annual Symposium of the Centre for Quantum Technologies (CQT), Singapore

On the occasion of CQT's 12th anniversary, we invite you to join us for a symposium on quantum technologies with strong international and local speakers. We welcome all interested researchers and industry colleagues to the event on 16 January 2020. Registration is free.

CQT was established in December 2007 as a national Research Centre of Excellence. It brings together physicists, computer scientists and engineers to do basic research on quantum physics and to build devices based on quantum phenomena.

CQT's annual symposia provide an opportunity to discuss hot topics aligned with the Centre's research. These research directions span atomic, molecular and optical physics, quantum information, quantum foundations and computer science.

SFAH Auditorium, Level 2, Shaw Foundation Alumni House
11 Kent Ridge Drive, Singapore 119244
SFAH on Google map

16 Jan 2020 Program
1:30pm Registration
1:55pm Opening and Welcome Remarks
2:00pm Marianna Safronova, University of Delaware
Atomic Clocks for Fundamental Physics - Time for Discovery
Arrow Abstract

The extraordinary advances in quantum control of matter and light have been transformative for precision measurements enabling probes of the most basic laws of Nature to gain a fundamental understanding of the physical Universe. Exceptional versatility, inventiveness, and rapid development of precision experiments supported by continuous technological advances and improved theory give a very high chance for paradigm-shifting discovery. The development of atomic clocks with systematic uncertainties in the 10-18 range enables searches for the variation of fundamental constants, dark matter, and violations of Lorentz invariance. I will give an overview of such clock applications including prospects for significantly improved sensitivity with highly charged ions and a nuclear clock.

3:00pm Piet Schmidt, Physikalisch-Technische Bundesanstalt
Quantum Logic Spectroscopy of Highly Charged Ions
Arrow Abstract

Highly charged ions (HCI) have many favourable properties for tests of fundamental physics and as potential next-generation optical atomic frequency standards [1]. For example, narrow optical fine-structure transitions have smaller polarizabilities and electric quadrupole moments, but much stronger relativistic, QED and nuclear size contributions to their binding energy compared to their (near)neutral counterparts. Therefore, HCI have been found to be among the most sensitive atomic species to probe for a possible variation of the fine-structure constant or dark matter coupling.

HCI can readily be produced and stored in an electron beam ion trap (EBIT). There, the most accurate laser spectroscopy on any HCI was performed on the 17 Hz wide fine-structure transition in Ar13+ with 400 MHz resolution, lagging almost twelve orders of magnitude behind state-of-the-art optical clocks. This was primarily limited by Doppler broadening of the megakelvin hot ion plasma in the EBIT [2]. The lack of a suitable optical transition for laser cooling and detection can be overcome through sympathetic cooling with a co-trapped Be+ ion [3]. Techniques developed for quantum information processing with trapped ions can be used to perform quantum logic spectroscopy [3]: A series of laser pulses transfers the internal state information of the Ar13+ ion after spectroscopy onto the Be+ ion for efficient readout.

We present the first coherent laser spectroscopy results of an HCI. Ar13+ are extracted from a compact EBIT [5], charge-to-mass selected and injected into a cryogenic Paul trap containing a crystal of laser-cooled Be+ ions [6]. By removing excess Be+ ions, a crystal composed of a Be+/Ar13+ ion pair can be obtained. First results on sympathetic ground state cooling and quantum logic spectroscopy of the Ar13+ P1/2-P3/2 fine-structure transition at 441 nm will be presented, improving the observed linewidth by more than eight orders of magnitude. Furthermore, excited state lifetimes and the first high-accuracy measurement of excited state g-factors demonstrate the versatility of the technique to access all relevant atomic parameters [7].

[1] M. G. Kozlov et al., Rev. Mod. Phys. 90, 045005 (2018).
[2] I. Draganić et al., Phys. Rev. Lett. 91, (2003).
[3] L. Schmöger et al., Science 347, 1233–1236 (2015).
[4] P. O. Schmidt et al., Science 309, 749–752 (2005).
[5] P. Micke et al., Rev. Sci. Instrum. 89, 063109 (2018).
[6] T. Leopold et al., Rev. Sci. Instrum. 90, 073201 (2019).
[7] P. Micke et al., Nature, in print.

Piet's Diagram

4:00pm Coffee/Tea Break
4:30pm Murray Barrett, Centre for Quantum Technologies, NUS
The CQT Lutetium Clock Project
Arrow Abstract

Singly ionized lutetium (176Lu+) is a relatively new clock candidate that was pioneered at CQT. The candidate has a number of attractive features for clock applications. It provides three independent clock transitions allowing consistency checks on error budgets through frequency comparisons within the one system. Two of the transitions allow long interrogation times relevant to current state-of-the-art lasers, and both have atomic properties that compare favourably to other leading clock candidates. In addition, we have recently begun working with multiple ions with a proof-of-concept demonstration that high accuracy multi-ion clock operation is feasible.

In this talk we will give an overview of the lutetium clock project highlighting key developments over the last five years, where we intend to go next, and how that may fit in to the technological landscape in Singapore.

5:30pm Marco Tomamichel, University of Technology Sydney
Using a Quantum Advantage to Show Quantum Computational Supremacy
Arrow Abstract

As larger and larger prototypes of quantum computers are being developed, one of the most exciting challenges in the theory of quantum computing is to find computational problems that can be solved by an intermediate-scale noisy quantum computer, but are beyond the capabilities of existing classical computers. In the first part of the talk I will introduce the basic concepts and review progress on this question, including the recent breakthrough by the Google team. In the second part of the talk, we construct a class of problems that show a quantum advantage: they can be solved by noisy quantum computers of constant circuit depth but require at least logarithmic depth classical circuits. The construction uses ideas from both nonlocal games and quantum communication.

6:30pm Networking Reception
8:00pm End of Symposium

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