Events

Abstract: This introductory talk visits the ultraviolet catastrophe, atomic bombs, atomic clocks, transistors, superconductivity, quantum entanglement and more. Find out how quantum physics has given us modern technologies and what future applications of quantum technologies could look like. There will be time left at the end of the talk for a Q&A session. Come with your burning questions! https://www.nlb.gov.sg/main/whats-on/event-detail?event-id=176102726630

Abstract: Progress toward a three qubit trapped ion quantum computer is reported. Independent control and readout of three 171Yb+ ions are achieved using a multi channel acousto optical modulator together with a multi channel photomultiplier tube. Intensity crosstalk errors are characterized, and compensation pulses are introduced to reduce these errors. The Mølmer–Sørensen two qubit gate is demonstrated across all three ion pairs. Single qubit gate performance is assessed via standard randomised benchmarking. Leading sources of gate infidelities are identified and mitigation strategies described. To end, the set-up is instead used as a quantum sensor, demonstrating that a single trapped ion is sensitive to mechanical vibrations of the vacuum chamber.

Abstract: Recent progress has brought physical error rates close to the threshold required for Quantum Error Correction (QEC). Yet, achieving reliable, high-fidelity operation at scale remains an open challenge. As systems grow, accurately characterizing noise becomes increasingly difficult: scaling up introduces intricate interactions among qubits, where crosstalk, non-Markovian dynamics, and parameter drift create emergent behavior that escapes traditional noise models. The resulting cascade of context-dependent effects exposes the limits of current abstractions and calls for a rethinking of the quantum computing stack and the gate model itself. In this talk, I will introduce a framework that aims to address this issue by extending the traditional gate model of quantum computing. Leveraging state-of-the-art control systems such as NVIDIA’s DGX Quantum, this architecture enables the fine-tuning of the pulse-level description of elementary circuit building blocks based on their particular location within a wider quantum circuit context, without any memory or execution overhead. I will also present a novel and efficient reinforcement learning framework that provides a fast, model-free way to infer and compensate for complex correlated errors, showing how AI-driven calibration can be embedded within the control system to achieve and maintain stability in minutes rather than the hours required by traditional closed-loop approaches. The presentation will conclude with an outlook on architectures enabling concurrent real-time decoding and adaptive in situ calibration during QEC operations. This approach illustrates how the relationship between physical and logical error rates must evolve dynamically to account for drift and circuit dependence, underscoring the importance of hybrid classical–quantum integration in the pursuit of practical fault tolerance.

Abstract: This talk will address the long-standing open problem of finding matching upper and lower bounds for quantum oblivious transfer and its application.   For the upper bound, optimal quantum oblivious transfer to date requires multiple calls to quantum weak coin flipping, whose composability is unknown. We prove that, despite failing in the abstract cryptography framework, quantum weak coin flipping is secure under sequential composition. This sequential composability can be leveraged to derive quantum oblivious transfer upper bounds. For the lower bound, we propose tight and robust consecutive measurement theorems that relate the information gained from two consecutive measurements to that gained from the first one alone. We derive a lower bound for quantum oblivious transfer from consecutive measurements and another one from pretty-good measurements, each outperforming the other in a different parameter regime. Finally, the no-go theorem for quantum oblivious transfer extends to other primitives, notably quantum homomorphic encryption. By constructing quantum oblivious transfer from quantum homomorphic encryption, we derive a no-go theorem for the latter.

Abstract: Superradiance stands as a hallmark phenomenon in collective quantum optics. Iwill show the unraveling of superradiant dynamics into individual quantumtrajectories via homodyne detection. Remarkably, despite the presence ofentanglement, these trajectories can be effectively treated as product statesfor describing local observables. This findings drastically simplies thecomplexity of superradiant phenomona and can lead to fully classcial and exactdescription in some scenerios, offering both analytical treatment and intuitiveunderstanding. Furthermore, I will show that our approach extends to regimesdominated by subradiant decay. Finally, I will present a novel emergentcollective behavior in waveguide QED uncovered by this trajectory-basedperspective, which renders superradiance robust to strongdisorders.   Ref: Xin H. H. Zhang, Daniel Malz, Peter Rabl, Phys. Rev. Lett. 135, 033602(2025); Xin H. H. Zhang, Daniel Malz, Peter Rabl, arXiv: 2510.13671.

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.