A von-Neumann-like photonic processor and its application in studying quantum signature of chaos.

Photonic quantum computation plays an important role and offers unique advantages. Two decades after the milestone work of Knill-Laflamme-Milburn, various architectures of photonic processors have been proposed, and quantum advantage over classical computers has also been demonstrated. It is now the opportune time to apply this technology to real-world applications. However, at current technology level, this aim is restricted by either programmability in bulk optics or loss in integrated optics for the existing architectures of processors, for which the resource cost is also a problem. Here we present a von-Neumann-like architecture based on temporal-mode encoding and looped structure on table, which is capable of multimode-universal programmability, resource-efficiency, phase-stability and software-scalability. In order to illustrate these merits, we execute two different programs with varying resource requirements on the same processor, to investigate quantum signature of chaos from two aspects: the signature behaviors exhibited in phase space (13 modes), and the Fermi golden rule which has not been experimentally studied in quantitative way before (26 modes). The maximal program contains an optical interferometer network with 1694 freely-adjustable phases. Considering current state-of-the-art, our architecture stands as the most promising candidate for real-world applications.

Reflective dielectric cavity enhanced emission from hexagonal boron nitride spin defect arrays.

Among the various kinds of spin defects in hexagonal boron nitride (hBN), the negatively charged boron vacancy (VB-) spin defect that can be site-specifically generated is undoubtedly a potential candidate for quantum sensing, but its low quantum efficiency restricts its practical applications. Here, we demonstrate a robust enhancement structure called reflective dielectric cavity (RDC) with advantages including easy on-chip integration, convenient processing, low cost and suitable broad-spectrum enhancement for VB- defects. In the experiment, we used a metal reflective layer under the hBN flakes, filled with a transition dielectric layer in the middle, and adjusted the thickness of the dielectric layer to achieve the best coupling between RDC and spin defects in hBN. A remarkable 11-fold enhancement in the fluorescence intensity of VB- spin defects in hBN flakes can be achieved. By designing the metal layer into a waveguide structure, high-contrast optically detected magnetic resonance (ODMR) signal (∼21%) can be obtained. The oxide layer of the RDC can be used as the integrated material to implement secondary processing of micro-nano photonic devices, which means that it can be combined with other enhancement structures to achieve stronger enhancement. This work has guiding significance for realizing the on-chip integration of spin defects in two-dimensional materials.

Coherent control of an ultrabright single spin in hexagonal boron nitride at room temperature.

Hexagonal boron nitride (hBN) is a remarkable two-dimensional (2D) material that hosts solid-state spins and has great potential to be used in quantum information applications, including quantum networks. However, in this application, both the optical and spin properties are crucial for single spins but have not yet been discovered simultaneously for hBN spins. Here, we realize an efficient method for arraying and isolating the single defects of hBN and use this method to discover a new spin defect with a high probability of 85%. This single defect exhibits outstanding optical properties and an optically controllable spin, as indicated by the observed significant Rabi oscillation and Hahn echo experiments at room temperature. First principles calculations indicate that complexes of carbon and oxygen dopants may be the origin of the single spin defects. This provides a possibility for further addressing spins that can be optically controlled.

Increases prognostic value of clinical-pathological nomogram in patients with esophageal squamous cell carcinoma.

Background: This study was intended to construct a brand new prognostic nomogram after combine clinical and pathological characteristics to increases prognostic value in patients with esophageal squamous cell carcinoma. Methods: A total of 1,634 patients were included. Subsequently, the tumor tissues of all patients were prepared into tissue microarrays. AIPATHWELL software was employed to explore tissue microarrays and calculate the tumor-stroma ratio. X-tile was adopted to find the optimal cut-off value. Univariate and multivariate Cox analyses were used to screen out remarkable characteristics for constructing the nomogram in the total populations. A novel prognostic nomogram with clinical and pathological characteristics was constructed on the basis of the training cohort (n=1,144). What's more performance was validated in the validation cohort (n=490). Clinical-pathological nomogram were assessed by concordance index, time-dependent receiver operating characteristic, calibration curve and decision curve analysis. Results: The patients can divide into two groups with cut-off value of 69.78 for the tumor-stroma ratio. It is noteworthy that the survival difference was noticeable (P<0.001). A clinical-pathological nomogram was constructed by combining clinical and pathological characteristics to predict the overall survival. In comparison with TNM stage, the concordance index and time-dependent receiver operating characteristic of the clinical-pathological nomogram showed better predictive value (P<0.001). High quality of calibration plots in overall survival was noticed. As demonstrated by the decision curve analysis, the nomogram has better value than the TNM stage. Conclusions: As evidently revealed by the research findings, tumor-stroma ratio is an independent prognostic factor in patients with esophageal squamous cell carcinoma. The clinical-pathological nomogram has an incremental value compared TNM stage in predicting overall survival.

Survival influence of gender on 42,345 patients with gastric cardia adenocarcinoma.

PURPOSE: Some studies indicated that gender is associated with prognostic of cancer, However, currently the prognostic value of gender for gastric cardia adenocarcinoma (GCA) survival is unclear. The aim of our study is to reveal the influence of gender on the prognosis of patients with GCA. PATIENTS AND METHODS: A total of 42,345 cases Chinese GCA patients were enrolled from our previously established GCA and esophageal cancer databases. The clinicopathological characteristics were retrieved from medical records in hospital. The follow-up was performed through letter, telephone or home interview. Among GCA patients, there were 32,544 (76.9%) male patients with the median age 62 years (range 17-97) and 9,801 (23.1%) female patients with the median age 61 years (range 17-95 years). The Chi-square test and Kaplan-Meier method were used to compare the continuous variables and survival. Cox proportional hazards model was used for competing risk analyses, hazard ratios (HRs) and 95% confidence intervals (CIs) were evaluated. RESULTS: Men had shorter GCA-specific survival than women by multivariate analysis (HR 1.114; 95% CI 1.061 to 1.169; P < 0.001). Whether premenopausal, perimenopausal or postmenopausal, the survival of women was better than that of men (premenopausal vs. male, P < 0.001; perimenopausal vs. male, P < 0.001; postmenopausal vs. male, P = 0.035). It was worth noting that in patients with stages I, II, III, and IV, female patients survive longer than male patients (P = 0.049; P = 0.011; P < 0.001; P = 0.044, respectively). CONCLUSION: Gender is an independent prognostic factor for patients with GCA. In comparison with men, women have a significantly better outcome. Smoking and drinking may be protective factors for male GCA patients.

A universal programmable Gaussian boson sampler for drug discovery.

Gaussian boson sampling (GBS) has the potential to solve complex graph problems, such as clique finding, which is relevant to drug discovery tasks. However, realizing the full benefits of quantum enhancements requires large-scale quantum hardware with universal programmability. Here we have developed a time-bin-encoded GBS photonic quantum processor that is universal, programmable and software-scalable. Our processor features freely adjustable squeezing parameters and can implement arbitrary unitary operations with a programmable interferometer. Leveraging our processor, we successfully executed clique finding on a 32-node graph, achieving approximately twice the success probability compared to classical sampling. As proof of concept, we implemented a versatile quantum drug discovery platform using this GBS processor, enabling molecular docking and RNA-folding prediction tasks. Our work achieves GBS circuitry with its universal and programmable architecture, advancing GBS toward use in real-world applications.

Coherent dynamics of multi-spin V[Formula: see text] center in hexagonal boron nitride.

Hexagonal boron nitride (hBN) has recently been demonstrated to contain optically polarized and detected electron spins that can be utilized for implementing qubits and quantum sensors in nanolayered-devices. Understanding the coherent dynamics of microwave driven spins in hBN is of crucial importance for advancing these emerging new technologies. Here, we demonstrate and study the Rabi oscillation and related phenomena of a negatively charged boron vacancy (V[Formula: see text]) spin ensemble in hBN. We report on different dynamics of the V[Formula: see text] spins at weak and strong magnetic fields. In the former case the defect behaves like a single electron spin system, while in the latter case it behaves like a multi-spin system exhibiting multiple-frequency dynamical oscillation as beat in the Ramsey fringes. We also carry out theoretical simulations for the spin dynamics of V[Formula: see text] and reveal that the nuclear spins can be driven via the strong electron nuclear coupling existing in V[Formula: see text] center, which can be modulated by the magnetic field and microwave field.

Serum Metabolomic Profiling Reveals Biomarkers for Early Detection and Prognosis of Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is one of the most common aggressive malignancies worldwide, particularly in northern China. The absence of specific early symptoms and biomarkers leads to late-stage diagnosis, while early diagnosis and risk stratification are crucial for improving overall prognosis. We performed UPLC-MS/MS on 450 ESCC patients and 588 controls consisting of a discovery group and two validation groups to identify biomarkers for early detection and prognosis. Bioinformatics and clinical statistical methods were used for profiling metabolites and evaluating potential biomarkers. A total of 105 differential metabolites were identified as reliable biomarker candidates for ESCC with the same tendency in three cohorts, mainly including amino acids and fatty acyls. A predictive model of 15 metabolites [all-trans-13,14-dihydroretinol, (±)-myristylcarnitine, (2S,3S)-3-methylphenylalanine, 3-(pyrazol-1-yl)-L-alanine, carnitine C10:1, carnitine C10:1 isomer1, carnitine C14-OH, carnitine C16:2-OH, carnitine C9:1, formononetin, hyodeoxycholic acid, indole-3-carboxylic acid, PysoPE 20:3, PysoPE 20:3(2n isomer1), and resolvin E1] was developed by logistic regression after LASSO and random forest analysis. This model held high predictive accuracies on distinguishing ESCC from controls in the discovery and validation groups (accuracies > 89%). In addition, the levels of four downregulated metabolites [hyodeoxycholic acid, (2S,3S)-3-methylphenylalanine, carnitine C9:1, and indole-3-carboxylic acid] were significantly higher in early cancer than advanced cancer. Furthermore, three independent prognostic markers were identified by multivariate Cox regression analyses with and without clinical indicators: a high level of MG(20:4)isomer and low levels of 9,12-octadecadienoic acid and L-isoleucine correlated with an unfavorable prognosis; the risk score based on these three metabolites was able to stratify patients into low or high risk. Moreover, pathway analysis indicated that retinol metabolism and linoleic acid metabolism were prominent perturbed pathways in ESCC. In conclusion, metabolic profiling revealed that perturbed amino acids and lipid metabolism were crucial metabolic signatures of ESCC. Both panels of diagnostic and prognostic markers showed excellent predictive performances. Targeting retinol and linoleic acid metabolism pathways may be new promising mechanism-based therapeutic approaches. Thus, this study would provide novel insights for the early detection and risk stratification for the clinical management of ESCC and potentially improve the outcomes of ESCC.

Generation of Spin Defects by Ion Implantation in Hexagonal Boron Nitride.

Optically addressable spin defects in wide-band-gap semiconductors as promising systems for quantum information and sensing applications have recently attracted increased attention. Spin defects in two-dimensional materials are expected to show superiority in quantum sensing due to their atomic thickness. Here, we demonstrate that an ensemble of negatively charged boron vacancies (VB -) with good spin properties in hexagonal boron nitride (hBN) can be generated by ion implantation. We carry out optically detected magnetic resonance measurements at room temperature to characterize the spin properties of ensembles of VB - defects, showing a zero-field splitting frequency of ∼3.47 GHz. We compare the photoluminescence intensity and spin properties of VB - defects generated using different implantation parameters, such as fluence, energy, and ion species. With the use of the proper parameters, we can successfully create VB - defects with a high probability. Our results provide a simple and practicable method to create spin defects in hBN, which is of great significance for realizing integrated hBN-based devices.

The prognostic value of keratin pearls in patients with esophageal squamous cell carcinoma.

Keratin pearls (KP) is an important indicator of the degree of tumor cell differentiation of esophageal squamous cell carcinomas (ESCC). However, the independent prognostic value of KP in ESCC patients remains unclear. The hematoxylin-eosin (H&E) stained tissue microarrays (TMAs) or whole slides of the patients were prepared to identify the existence of KP. Kaplan-Meier (KM) survival analysis as well as univariate and multivariate Cox regression analyses were used to evaluate the prognostic value of KP. A nomogram based on KP and other clinicopathologic characteristics was constructed. The C-index, calibration curve, Receiver Operating Characteristic (ROC) curve, and Decision Curve Analysis (DCA) were used to evaluate the nomogram. The results indicated KP is a protective factor against lymph node metastasis and is closely associated with the differentiation degree in ESCC patients. KM survival analysis showed that the overall survival (OS) of patients with KP was significantly better than for patients without KP. In addition, multivariate Cox regression analysis revealed that KP was an independent predictor of OS. Furthermore, ROC curve demonstrated that KP combined with differentiation degree could more accurately predict the 5-year survival rate than differentiation degree alone. Importantly, the nomogram showed good discrimination and calibration abilities in both training and validation groups, which could more accurately predict the 3-, 5-, and 10-year survival rates of ESCC patients and adds to the predictive value of TNM stage alone. In conclusion, KP is an independent predictor of prognosis in patients with ESCC and provides incremental prognostic value to degree of differentiation.

Experimental Observation of Coherent-Information Superadditivity in a Dephrasure Channel.

We present an experimental approach to construct a dephrasure channel that contains both dephasing and erasure noises and can be used as an efficient tool to study the superadditivity of coherent information. Using a three-fold dephrasure channel, the superadditivity of coherent information is observed, and a substantial gap is found between the zero single-letter coherent information and zero quantum capacity. Particularly, we find that, when the coherent information of n channel uses is zero, with a larger number of channel uses the quantum capacity becomes positive. These phenomena exhibit a more obvious superadditivity of coherent information than previous works and demonstrate a higher threshold for nonzero quantum capacity. Such novel channels built in our experiment also can provide a useful platform to study the nonadditive properties of coherent information and quantum channel capacity.

Experimental Investigation of State Distinguishability in Parity-Time Symmetric Quantum Dynamics.

Comprehensive study on parity-time (PT) symmetric systems demonstrates the novel properties and innovative application of non-Hermitian physics in recent years. In the quantum regime, PT symmetric physics exhibits unique quantum dynamical behaviors such as spontaneous state-distinguishability oscillation. However, the construction and control of a PT symmetric quantum system are still challenging, that and restrict the experimental investigation of PT symmetric quantum nature and application. In this Letter, we propose and construct a recycling-structure PT symmetric quantum simulator for the first time, which can effectively simulate the discrete-time dynamical process of a PT symmetric quantum system in both unbroken and broken phases, to be different from our previous work [J.-S. Tang, et al., Nat. Photonics 10, 642 (2016)]. We investigate the dynamical features of quantum state distinguishability based on the PT symmetric simulator. Our results demonstrate the novel PT symmetric quantum dynamics characterized by the periodical oscillation of state distinguishability in the unbroken phase, and the monotonic decay of that in the broken phase. This work also provides a practical experimental platform for the future intensive study of PT symmetric quantum dynamics.

Experimental Investigation of Quantum PT-Enhanced Sensor.

PT-symmetric theory is developed to extend quantum mechanics to a complex region, but it wins its great success first in classical systems, for example, optical waveguides and electric circuits, etc., because there are so many counterintuitive phenomena and striking applications, including unidirectional light transport, PT-enhanced sensors (one kind of exceptional-point-based sensor), and wireless power transfer. However, these phenomena and applications are mostly based on the ability to approach a PT-symmetric broken region, which makes it difficult to transfer them to the quantum regime, since the broken quantum PT-symmetric system has not been constructed effectively, until recently several methods have been raised. Here, we construct a quantum PT-symmetric system assisted by weak measurement, which can effectively transit from the unbroken region to the broken region. The full energy spectrum including the real and imaginary parts is directly measured using weak values. Furthermore, based on the ability of approaching a broken region, we for the first time translate the previously mentioned PT-enhanced sensor into the quantum version, and investigate its various features that are associated to the optimal conditions for sensitivity enhancement. In this experiment, we obtain an enhancement of 8.856 times over the conventional Hermitian sensor. Moreover, by separately detecting the real and imaginary parts of energy splitting, we can derive the additional information of the direction of perturbations. Our work paves the way of leading classical interesting PT phenomena and applications to their quantum counterparts. More generally, since the PT system is a subset of non-Hermitian systems, our work will be also helpful in the studies of general exception point in the quantum regime.