Lab

We demonstrate experimentally a protocol for superresolution quantum sensing that resolves two incoherent signals with sub-kHz frequency separation using a solid-state spin sensor. By utilizing the naturally occurring signal noise, we identify optimal interrogation times to make the estimation uncertainty remains finite even when the signal frequencies approach each other.

We propose a novel magnetic imaging protocol that achieves angstrom-scale resolution by combining spin defects in van der Waals materials and terahertz (THz) scattering scanning near-field optical microscopy.

Entanglement critically underpins the cutting-edge quantum technologies as well as a plethora of quantum foundational problems. Identifying universal principles for efficient scalable entanglement production, particularly in an exponentially fast, remains an important challenge. Now, by unveiling a link to the operator delocalizing dynamics on a meticulously crafted correlation landscape, a comprehensive understanding for the physical mechanism driving rapid entanglement production is established, which could help pinpoint explicit interacting many-body systems to realize the ambitious goal of exponentially fast generation of many-particle entangled states.

This work bridges topology and quantum metrology, demonstrating how topological characteristics within band structures, namely Berry curvature and Chern number, set fundamental limits on metrological properties, with experimental validation in an emulated Chern insulator.

Entanglement is NOT free! A strong precision limit of quantum metrology accounting for the preparation complexity of many-particle entangled states is established, revealing a fundamental constraint for reaching the elusive Heisenberg limit and identifying the essential features of many-body systems for achieving the quantum advantage.

Quantum sensing exploits fascinating features of quantum phenomena. A framework utilizing critical quantum dynamics to enhance the sensing performance is developed, providing an experimentally feasible pathway towards the implementation of criticality-enhanced quantum sensing.

Efforts are put into extending quantum enhanced sensing into the non-Hermitian regime of quantum world! A pseudo-Hermitian single-qubit sensor without involving the exceptional point is designed, demonstrating potential advantages to overcome noises that cannot be averaged out by repetitive measurements

Geometry and topology of quantum states, characterized by the quantum geometric tensor (QGT), are fundamental concepts in quantum mechanics. A first experimental measurement of the complete QGT by parametric modulations of the quantum system is demonstrated, establishing coherent dynamical responses as a versatile probe for quantum geometry and topology.

A hybrid quantum thermometer composed of bulk diamond with ensemble NV centers and gadolinium magnetic flux concentrators, achieves a submicrokelvin resolution. Near the critical point, the spin resonance to temperature is about 774 times enhanced compared with that of bare NV centers.

By engineering electric potential of a trapped electron system, the motional states of the trapped electron can obtain giant electric dipole moments, exceeding those attainable with Rydberg atoms. This artificial electric dipole may provide a potential platform for quantum technologies such as ultrahigh-sensitivity electric-field sensing.