Advancing the frontiers of quantum science and engineering

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: Density Functional Theory (DFT) is a widely used framework for electronic structure calculations. In this talk, I will present recent progress in the development of Density Potential Functional Theory (DPFT), a formulation of DFT that offers favourable scaling compared to conventional approaches such as Kohn–Sham DFT. I will show how DPFT can be used to approximate the electron density in position space and present results for a simple model system consisting of two electrons confined in a Hooke atom. I will then introduce momentum-DPFT, which allows the electron density to be approximated directly in momentum space, and revisit the Hooke atom to present the corresponding momentum densities. Beyond the theoretical framework, I will also discuss numerical aspects of DPFT, highlighting how various approximations and computational techniques are allowing us to simulate densities on increasingly large lattices and in higher dimensions.

Venue: CQT Level 3 Seminar Room, S15-03-15

Abstract: Fault-tolerant logical entangling gates are essential for scalable quantum computing, but are limited by the error rates and overheads of physical two-qubit gates and measurements. To address this limitation, we introduce phantom codes—quantum error-correcting codes that realize entangling gates between all logical qubits in a code block purely through relabelling of physical qubits during compilation, yielding perfect fidelity with no spatial or temporal overhead. We present a systematic study of such codes. First, we identify phantom codes using complementary numerical and analytical approaches. We exhaustively enumerate all 27 billion inequivalent CSS codes up to n = 14 and identify additional instances up to n = 21 via SAT-based methods. We then construct higher-distance phantom-code families using quantum Reed-Muller codes and the binarization of qudit codes. Across all identified codes, we characterize other supported fault-tolerant logical Clifford and non-Clifford operations. Second, through end-to-end noisy simulations with state preparation, full QEC cycles, and realistic physical error rates, we demonstrate scalable advantages of phantom codes over the surface code across multiple tasks. We observe a one-to-two order-of-magnitude reduction in logical infidelity at comparable qubit overhead for GHZ-state preparation and Trotterized many-body simulation tasks, given a modest preselection acceptance rate. Our work establishes phantom codes as a viable architectural route to fault-tolerant quantum computation with scalable benefits for workloads with dense local entangling structure, and introduces general tools for systematically exploring the broader landscape of quantum error-correcting codes. https://arxiv.org/abs/2601.20927

The Quantum Information Processing Conference (QIP) is the largest quantum information processing technology conference, which annually gathers the world’s brightest researchers and industry leaders for a week long program to present and discuss the latest achievements in quantum computing, cryptography, information theory, mathematics and physics. Recent editions have drawn nearly 1000 participants. In 2027, CQT will host the 30th edition of this conference in Singapore. QIP2027 will take place 20-26 February 2027.

The International Conference on Women in Physics (ICWIP) of the International Union of Pure and Applied Physics (IUPAP) will take place in the National University Singapore (NUS) during 7-11 June 2027, hosted by the Physics Department, NUS and the Centre for Quantum Technologies, Singapore. The ICWIP2027 is the 9th in a series of triennial conferences by IUPAP since 2002 that brings together practitioners from all over the world in order to deliberate on both topics in physics and processes within physics practice, with the goal of transforming physics into a welcoming inclusive enterprise for everyone. The conference will feature inspiring keynote talks by eminent women scholars, sessions where participants can present their own research in physics and on equity and inclusion in physics, interactive workshops to engage with the barriers to equity and inclusion in physics, call-to-action sessions on recommendations for the profession and more...