arXiv subjects

Haifei Wang

Publications and source records attributed to Haifei Wang.

4 recordsLinked to original sources

arXiv2026

Experimental High-Dimensional Quantum Overlapping Tomography

Large-scale quantum systems have advanced rapidly via the exploration of more particles and higher dimensions, offering great potential for developing quantum technologies. However, their characterization becomes prohibitive with increasing local dimensionality and particle number. Here we propose high-dimensional quantum overlapping tomography based on a graph-theoretic formulation, which allows one to efficiently reconstruct few-body marginals of multipartite high-dimensional quantum systems. We experimentally realize it on a photonic four-party entangled state in a $4 \times 4 \times 2 \times 2$ system. Using measurements in mutually unbiased bases, we reconstruct all six two-body marginals with only 25 projective measurement settings, compared with 94 and 225 settings for independent tomography of all two-body reduced states and full state tomography, respectively. The reconstructed marginals reveal a layered entanglement structure vital for high-dimensional quantum networks. We further show that these marginals enable more noise-resilient certification of multipartite high-dimensional entanglement than the fidelity-based criterion. Our work thus offers a scalable route for learning multidimensional quantum systems.

quant-ph↗

arXiv2025

Optimal Overlapping Tomography

Characterising large-scale quantum systems is central to fundamental physics and essential for applications of quantum technologies. While a full characterisation requires exponentially increasing resources, focusing on application-relevant information can often lead to significantly simplified analysis. Overlapping tomography is such a scheme, allowing one to obtain all the information contained in specific subsystems of multiparticle quantum systems in an efficient manner, but the ultimate limits of this approach remain elusive. We present protocols for overlapping tomography that are optimal with respect to the number of measurement settings. First, by providing algorithmic approaches based on graph theory we find the minimal number of Pauli settings, relating overlapping tomography to the problem of covering arrays in combinatorics. This significantly reduces the number of measurement settings, showing for instance that two-body overlapping tomography of nearest neighbours in qubit systems with planar topologies can always be performed with nine Pauli settings. Second, we prove that using general projective measurements, all $k$-body marginals can be reconstructed with only $3^k$ settings, independently of the system size. Finally, we demonstrate the practical applicability of our methods in a six-photon experiment. Our results will find applications in learning noise and interaction patterns in quantum computers as well as characterising fermionic systems in quantum chemistry.

quant-ph↗

arXiv2017

Infrared properties of micromachined vanadium oxide thin films

This paper discusses questions of synthesizing and pressing vanadium oxides to create film-forming materials that can be used in producing optical coatings. Based on the film-forming materials thus created, technological processes have been developed for fabricating coatings from vanadium dioxide by two methods of producing thin films: vacuum evaporation and magnetron sputtering. Questions of using films made from vanadium oxide in optical instrumentation are considered.

cond-mat.mtrl-sci↗

arXiv2016

Nanoscale force sensor and actuator with carbon-nanotube network

Actuators at the nanoscale are assuming great important in todays shrinking electronics industry where a system-on-chip approach is used to integrate multi-functional systems and devices. Integration of sensors, actuators, information processing, and storage have become extremely important, more so at the sub-micrometer scale. Here we utilized vertically aligned carbon nanotube forests bonded onto a piezoelectric substrate to provide sensing of nanoscale forces and actuation on the same platform. This is a demonstration of integration of two important functions using the functionality of nanomaterials. This has immediate utility in many areas including outer space exploration, portable consumer electronics, embedded systems, etc.

cond-mat.mes-hall↗