Advancing the frontiers of quantum science and engineering

Abstract: In my undergraduate FYP, I focused on working towards the potential for implementation of atomic frequency combs as a reliable and efficient quantum memory scheme. Rare-earth ion doped crystals are the medium of choice as they have been proven to excel in areas of storage time, efficiency, bandwidth, memory wavelength compatibility, and multimodal capacity. Specifically, I used an Erbium ion doped Calcium Tungstate (CaWO4) crystal. CaWO4 has not been researched much yet, albeit its known potential as a suitable candidate for quantum memory. Hence, I hope to be able to bring new findings to the table. In my presentation, I will focus on the motivations behind my FYP, simulations of two level atomic ensemble two pulse photon echo and AFC, and lastly experimental attempts and investigations on the spectral tailoring method called spectral hole burning on the Er3+:CaWO4 crystal.

ACTI will bring together the growing community of ion-trappers from Asia and across the globe. As an inaugural conference, this year will highlight various scientific fields covered by trapped ion research within Asia and facilitate meaningful exchange between junior and senior members of the different groups.

Abstract: Nonlocality is one of the key features of quantum physics, whichis revealed through the violation of a Bell inequality. In large multipartitesystems, however, characterizing nonlocality quickly becomes challenging.In this talk, I present scalable tools to study and certify Bellnonlocality in this setting. For one-dimensional infinite translationallyinvariant systems with finite-range correlators, we show how to constructtensor representations of Bell inequalities and optimize them usingtensor-network contractions in tropical algebra. For quantum devicecertification, we introduce energy as a witness of many-body Bell correlationsand as a tool for certifying Bell-correlation depth. With an appropriateHamiltonian acting as a Bell-correlation witness, variationally lowering thesystem’s energy across specific thresholds certifies increasingBell-correlation depth directly from experimental data.

Abstract: Optical systems enable the generation of ultra-large-scale entangled states with compact, constant-size hardware via time-domain multiplexing. Based on one of these states, we have built an analog optical quantum processor that executes universal Gaussian operations. Moreover, we introduce a software layer designed for flexible programming of this processor. In this talk, we will present the principle of the analog optical quantum computer and details of our current architecture.

Abstract: We aim to realize an ultrafast optical quantum computer in the future. In this talk, I will introduce the latest technologies for that, such as ultrafast homodyne detection, all-optical feedforward, CW-Pulse architecture.

The goal of this workshop is to bring the active research community together to discuss the progress, challenges and new possible directions for quantum repeaters and networks. We invite researchers working on key enabling technologies and system integration, protocols for connecting repeaters across network links with high fidelity, architectures for large-scale networks, and applications of distributed quantum entanglement. The WQRN has been and continues to be a limited-attendance, few-day workshop, in which participants are given the opportunity to share ideas, directions, and concerns to advance the state of the field. Talks are by invitation only and catered to broadly cover the applications, theory, components, and worldwide directions in quantum repeaters and networks. These talks frame group discussion sessions for which all participants are welcome to contribute; participants are also welcome to contribute to a poster session.

Abstract: A many-body system, whether in contact with a large environment or evolving under complex dynamics, can typically be modeled as occupying the thermal state singled out by Jaynes' maximum entropy principle. Here, we find analogous fundamental principles identifying a noisy quantum channel T to model the system's dynamics, going beyond the study of its final equilibrium state. Our maximum channel entropy principle states that T should maximize the channel's entropy, suitably defined, subject to any available macroscopic constraints. These may correlate input and outputs, and may lead to restricted or partial thermalizing dynamics including thermalization with average energy conservation. This principle is reinforced by an independent extension of the microcanonical derivation of the thermal state to channels, which leads to the same T. Our technical contributions include a derivation of the general mathematical structure of T, a custom postselection theorem relating an arbitrary permutation-invariant channel to nearby i.i.d. channels, as well as novel typicality results for quantum channels for noncommuting constraints and arbitrary input states. We propose a learning algorithm for quantum channels based on the maximum channel entropy principle, demonstrating the broader relevance of T beyond thermodynamics and complex many-body systems. (Based on the works [arXiv:2508.03993] and [arXiv:2508.03994].)

Abstract: Organised by Singapore’s Centre for Quantum Technologies (CQT), the hackamonth is an innovative approach to hackathons: a month-long, collaborative experience where participants work on quantum computing for meaningful problems. Typical hackathons are short and competitive, ending with prizes. With our hackamonth, we want to have real scientific impact.

Abstract: QCamp is a one-week summer school for curious and inquisitive minds who wish to explore and understand the physical laws that govern the world’s smallest scales: quantum physics. The scope of QCamp is to provide vivid demonstrations of these laws, offer career advice, as well as to help students build a technical foundation for independent exploration of this world. QCamp is organised by the Centre for Quantum Technologies (CQT) at the National University of Singapore.

The one-day Flash QCamp for curious and inquisitive minds to get a taster in quantum technologies.