Inferring Physical Properties of Symmetric States from the Fewest Copies.

Learning physical properties of high-dimensional states is crucial for developing quantum technologies but usually consumes an exceedingly large number of samples which are difficult to afford in practice. In this Letter, we use the methodology of quantum metrology to tackle this difficulty, proposing a strategy built upon entangled measurements for dramatically reducing sample complexity. The strategy, whose characteristic feature is symmetrization of observables, is powered by the exploration of symmetric structures of states which are ubiquitous in physics. It is provably optimal under some natural assumption, efficiently implementable in a variety of contexts, and capable of being incorporated into existing methods as a basic building block. We apply the strategy to different scenarios motivated by experiments, demonstrating exponential reductions in sample complexity.

Non-Hermitian Floquet Topological Matter-A Review.

The past few years have witnessed a surge of interest in non-Hermitian Floquet topological matter due to its exotic properties resulting from the interplay between driving fields and non-Hermiticity. The present review sums up our studies on non-Hermitian Floquet topological matter in one and two spatial dimensions. We first give a bird's-eye view of the literature for clarifying the physical significance of non-Hermitian Floquet systems. We then introduce, in a pedagogical manner, a number of useful tools tailored for the study of non-Hermitian Floquet systems and their topological properties. With the aid of these tools, we present typical examples of non-Hermitian Floquet topological insulators, superconductors, and quasicrystals, with a focus on their topological invariants, bulk-edge correspondences, non-Hermitian skin effects, dynamical properties, and localization transitions. We conclude this review by summarizing our main findings and presenting our vision of future directions.

Estimating Coherence Measures from Limited Experimental Data Available.

Quantifying coherence has received increasing attention, and considerable work has been directed towards finding coherence measures. While various coherence measures have been proposed in theory, an important issue following is how to estimate these coherence measures in experiments. This is a challenging task, since the state of a system is often unknown in practical applications and the accessible measurements in a real experiment are typically limited. In this Letter, we put forward an approach to estimate coherence measures of an unknown state from any limited experimental data available. Our approach is not only applicable to coherence measures but can be extended to other resource measures.

Primary granulomatous hypophysitis: a case report and literature review.

Primary granulomatous hypophysitis (PGH) is a rarely occurred inflammatory disease of unknown etiology. We retrospective review a case of PGH treated by microsurgical transsphenoidal approach and review the appropriately documented cases of PGH collected from the literatures. The patient was a 56-year-old female who presented with 4 months history of headache and 2 months history of polyuria and polydipsia. Clinic examination did not find remarkable neurological signs, except endocrinological abnormalities of secondary hypothyroidism and hypocorticalism. MRI revealed a symmetric sellar mass, which was isointensity as gray matter on T1-weighted and T2-weighted images with heterogeneous enhancement. The mass was partially resected via transsphenoidal approach. Histological assessment revealed a non-necrotizing granulomatous lesion with chronic inflammation. Although the resection was limited, repeatedly MRI scanning in 3 months following surgery revealed almost normal pituitary soft tissue without evidence of the lesion. Searching in PubMed, we found 21 papers published from 1985 to 2009 and 37 patients with PGH were reported. In order to identify the clinical and radiological presentation, treatment strategy, and prognosis of PGH, we analyzed these 38 cases together. The results indicate that the clinical presentations and radiological signs are helpful for the diagnosis of PGH. The outcome of surgery for PGH is favorable for immediate mass reduction and histological diagnosis, but hormone replacement is required in most cases and long-term follow up is very important.