10 citations · 29 across the 28 of their papers we have counts for
30 papers · 1 filter
Kramers' Theorem Leaves a Topological Footprint in Classical Records
Chon-Fai Kam, Kai-Wen Wong
Time reversal squares to on a half-integer spin, so every state is orthogonal to its time reverse. This sign has been read only from quantum objects. The equilibrium state…
Forbidden Subspaces in Quantum State Smoothing
Chon-Fai Kam, Kai-Wen Wong
A system between a preparation and a post-selection has had no agreed state since 1964. With positivity as the criterion, a post-selection admits an interval of orderings around th…
Stellar rank under the contraction of SU(1,1) to the Heisenberg-Weyl group
Chon-Fai Kam
Under the contraction of to the Heisenberg-Weyl group, the zeros of the Husimi function of a state redistribute according to a single scale, and we determine which of the…
Hudson's theorem fails for the SU(1,1) discrete series
Chon-Fai Kam
Hudson's theorem states that a pure state of a bosonic mode has a non-negative Wigner function if and only if it is Gaussian. It underwrites the reading of Wigner negativity as a f…
Restricting the effects hides a nonphysical symmetry from every causal structure
Chon-Fai Kam
Real-amplitude quantum theory is the subtheory of quantum theory invariant under complex conjugation, and experiments in networks of independent sources have measured correlations…
Nodal obstruction to conditioned-diffusion representations of the weak momentum
Chon-Fai Kam, Kai-Wen Wong
Quantum Schrödinger bridge constructions establish the existence of a conditioned process under a positivity hypothesis on the endpoint data, and three independent ones adopt it. W…
Numerical Evaluation of ZX Calculus Optimization for Solovay Kitaev Quantum Circuit Synthesis
Dulari De Silva, Anuradha Mahasinghe, Chon-Fai Kam +3
Fault-tolerant architectures implement non-Clifford T gates through magic-state distillation, so the T-count of a synthesized circuit dominates its physical cost. The Solovay-Kitae…
An Exactness Barrier for ZX-Calculus Optimization of Synthesized Clifford+T Circuits
Chon-Fai Kam, Anuradha Mahasinghe, Kaushika De Silva +2
Gate synthesis and circuit optimization are usually studied separately, and evidence on their interaction is contradictory: ZX-calculus rewriting removes a stable fraction of Solov…
Near-Optimal Mode Scaling for Finite-Dimensional Boson Sampling via Lie-Algebraic Leakage Bounds
Chon-Fai Kam, En-Jui Kuo
Boson sampling demonstrates quantum advantage through the interference of indistinguishable particles, with output probabilities governed by matrix permanents. Realizing it on dete…
Wavelet Variance Equipartition as a Threshold for World-Model Quality and Quantum Kernel TN-Simulability
Chon-Fai Kam, Xavier Cadet, Miloud Bessafi +1
While world models learn compact representations of complex environments, they lack a physics-grounded metric to assess the structural fidelity of their latent spaces. We identify…
Majorana Constellations: A Geometric Lens on Multipartite Entanglement and Geometric Phases
Chon-Fai Kam
The Majorana stellar representation maps a pure spin- state to points on a sphere. This review develops it with entanglement as the organising principle, and two objects re…
Non-variational supervised quantum kernel methods: a review
John Tanner, Chon-Fai Kam, Jingbo Wang
Quantum kernel methods (QKMs) have emerged as a prominent framework for supervised quantum machine learning. Unlike variational quantum algorithms, which rely on gradient-based opt…
Three-Axis Spin Squeezed States Associated with Excited-State Quantum Phase Transitions
Chon-Fai Kam
Spin squeezing in collective atomic ensembles enables quantum-enhanced metrology by reducing noise below the standard quantum limit through nonlinear interactions. Extending the on…
Quantum Supremacy through Fock State boson Sampling with Transmon Qubits
Chon-Fai Kam, En-Jui Kuo
Transmon qubits have traditionally been regarded as limited to random circuit sampling, incapable of performing Fock state boson sampling, a problem known to be classically intract…
Nonlinear optical analogues of quantum phase transitions in a squeezing-enhanced LMG model
Chon-Fai Kam
We investigate nonlinear optical analogues of quantum phase transitions within a squeezing-enhanced generalized Lipkin-Meshkov-Glick (LMG) model, focusing on excited-state quantum…
Beyond Boson Sampling: Higher Spin Sampling as a Practical Path to Quantum Supremacy
Chon-Fai Kam, En-Jui Kuo
Since the dawn of quantum computation science, a range of quantum algorithms have been proposed, yet few have experimentally demonstrated a definitive quantum advantage. Shor's alg…
Nonlinear optical realization of non-integrable phases accompanying quantum phase transitions
Chon-Fai Kam
In this work, we propose an experimentally feasible nonlinear optical realization of a type of non-integrable phase found in interacting quantum systems at quantum phase transition…
Quantum-Secured Device-Independent Global Positioning System
Chon-Fai Kam, En-Jui Kuo
This paper introduces a novel device-independent quantum self-testing protocol designed specifically for multipartite quantum communication. By exploiting the quantum rigidity in B…
Super-Poissonian Squeezed Light in the Deep Strong Regime of the Quantum Rabi Model
Chon-Fai Kam, Xuedong Hu
By analytically solving the quantum Rabi model, we investigate the photonic properties of its ground eigenstate. In particular, we find that in the deep strong coupling regime, whe…
What is Entanglement?
Chon-Fai Kam, Zhong-Tang Wu
Entanglement, a puzzle since Einstein's time, has become increasingly crucial with the rise of quantum computation. But what exactly is it? Historically , entanglement can be preci…
Analytical approximations for generalized quantum Rabi models
Chon-Fai Kam, Yang Chen
The quantum Rabi model is essential for understanding interacting quantum systems. It serves as the simplest non-integrable yet solvable model describing the interaction between a…
Sub-microsecond high-fidelity dispersive readout of a spin qubit with squeezed photons
Chon-Fai Kam, Xuedong Hu
Fast and high-fidelity qubit measurement is essential for realizing quantum error correction, which is in turn a key ingredient to universal quantum computing. For electron spin qu…
Analytical Approximations for Generalized Landau-Zener Transitions in Multi-level Non-Hermitian Systems
Chon-Fai Kam, Yang Chen
We study the dynamics of non-adiabatic transitions in non-Hermitian multi-level parabolic models where the separations of the diabatic energies are quadratic function of time. The…
Genuine tripartite entanglement as a probe of quantum phase transitions in a spin-1 Heisenberg chain with single-ion anisotropy
Chon-Fai Kam, Yang Chen
We study the quantum phase transitions of spin-1 Heisenberg chains with an easy-axis anisotropy and a uniaxial single-ion anisotropy using a multipartite entanglement appro…