Agnostic Phase Estimation.

The goal of quantum metrology is to improve measurements' sensitivities by harnessing quantum resources. Metrologists often aim to maximize the quantum Fisher information, which bounds the measurement setup's sensitivity. In studies of fundamental limits on metrology, a paradigmatic setup features a qubit (spin-half system) subject to an unknown rotation.

Entanglement Assisted Probe of the Non-Markovian to Markovian Transition in Open Quantum System Dynamics.

We utilize a superconducting qubit processor to experimentally probe non-Markovian dynamics of an entangled qubit pair. We prepare an entangled state between two qubits and monitor the evolution of entanglement over time as one of the qubits interacts with a small quantum environment consisting of an auxiliary transmon qubit coupled to its readout cavity. We observe the collapse and revival of the entanglement as a signature of quantum memory effects in the environment.

Parity-Time Symmetric Holographic Principle.

Originating from the Hamiltonian of a single qubit system, the phenomenon of the avoided level crossing is ubiquitous in multiple branches of physics, including the Landau-Zener transition in atomic, molecular, and optical physics, the band structure of condensed matter physics and the dispersion relation of relativistic quantum physics. We revisit this fundamental phenomenon in the simple example of a spinless relativistic quantum particle traveling in (1+1)-dimensional space-time and establish its relation to a spin-1/2 system evolving under a PT-symmetric Hamiltonian. This relation allows us to simulate 1-dimensional eigenvalue problems with a single qubit.

Context-dependent regulation of Notch signaling in glial development and tumorigenesis.

In the mammalian brain, Notch signaling maintains the cortical stem cell pool and regulates the glial cell fate choice and differentiation. However, the function of Notch in regulating glial development and its involvement in tumorigenesis have not been well understood. Here, we show that Notch inactivation by genetic deletion of in stem cells decreases astrocytes but increases oligodendrocytes with altered internal states.

Hyperactive DNA Cutting for Unbiased UHPLC-MS/MS Quantification of Epigenetic DNA Marks by Engineering DNase I Mutants.

Epigenetic DNA modifications, such as 5-methylcytosine, 5-hydroxymethylcytosine, and 5-formylcytosine, are associated with a variety of diseases and potential biomarkers for cancer diagnosis and therapy. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays are considered to be the gold standard for qualitative and quantitative detection of DNA modifications. DNA digestion for converting long DNA polymer into 2'-deoxynucleosides is an important preprocessing step to achieve sensitive and accurate LC-MS/MS quantification.

Zero-Interfacing μHPLC to ICPMS.

The chromatography-mass spectrometry hyphenated technique is the most widely adopted tool for quantifying trace analytes in a complex biosample. One issue we frequently encountered, however, is that the separated analyte-containing chromatographic peaks broaden and even remix prior to mass spectrometric quantification due to the inevitable molecular diffusion within the dead-volume introduced by hyphenation. We developed a zero-interfacing approach for coupling microbore (μ) HPLC with inductively coupled plasma mass spectrometry (ICPMS).

Observation of parity-time symmetry breaking in a single-spin system.

Steering the evolution of single spin systems is crucial for quantum computing and quantum sensing. The dynamics of quantum systems has been theoretically investigated with parity-time-symmetric Hamiltonians exhibiting exotic properties. Although parity-time symmetry has been explored in classical systems, its observation in a single quantum system remains elusive.