In the asymptotic theory of quantum hypothesis testing, the minimal error probability of the first kind jumps sharply from zero to one when the error exponent of the second kind passes by the point ...of the relative entropy of the two states in an increasing way. This is well known as the direct part and strong converse of quantum Stein's lemma. Here we look into the behavior of this sudden change and have make it clear how the error of first kind grows smoothly according to a lower order of the error exponent of the second kind, and hence we obtain the second-order asymptotics for quantum hypothesis testing. This actually implies quantum Stein's lemma as a special case. Meanwhile, our analysis also yields tight bounds for the case of finite sample size. These results have potential applications in quantum information theory. Our method is elementary, based on basic linear algebra and probability theory. It deals with the achievability part and the optimality part in a unified fashion.
We consider the problem of testing multiple quantum hypotheses $\left\{ {\rho _1^{ \otimes n},...,\rho _r^{ \otimes n}} \right\}$, where an arbitrary prior distribution is given and each of the r ...hypotheses is n copies of a quantum state. It is known that the minimal average error probability Pe decays exponentially to zero, that is, Pe = exp{–ξn + 0(n)}. However, this error exponent ξ is generally unknown, except for the case that r = 2. In this paper, we solve the long-standing open problem of identifying the above error exponent, by proving Nussbaum and Szkola's conjecture that ξ = mini≠j C(ρi, ρj). The right-hand side of this equality is called the multiple quantum Chernoff distance, and $C\left( {{\rho _i},{\rho _j}} \right): = \max {}_{0 \leqslant s \leqslant 1}\left\{ { - \log Tr\rho _i^s\rho _j^{1 - s}} \right\}$ has been previously identified as the optimal error exponent for testing two hypotheses, $\rho _i^{ \otimes n}$ versus $\rho _j^{ \otimes n}$. The main ingredient of our proof is a new upper bound for the average error probability, for testing an ensemble of finite-dimensional, but otherwise general, quantum states. This upper bound, up to a states-dependent factor, matches the multiple-state generalization of Nussbaum and Szkola's lower bound. Specialized to the case r = 2, we give an alternative proof to the achievability of the binary-hypothesis Chernoff distance, which was originally proved by Audenaert et al.
A plug-and-play surface plasmon resonance (SPR) dual-parameter optical fiber biosensor is reported, in which Au film was firstly coated on the fiber surface for exciting SPR and the end half of the ...Au film was modified with Au nanoparticles to generate double SPR resonance valleys. For simultaneous detecting of glucose and cholesterol concentrations, modified P-mercaptophenylboronic acid (PMBA) and β-cyclodextrin (β-CD) were subsequently coated on the surface of sensor probe. Due to the cis-diol structure of glucose, it can interact with PMBA, leading to a red shift of one SPR resonant valley, whose maximum wavelength shift is 11.228 nm in the range of 0–1.7 mM glucose concentration. On the same time, the cholesterol molecules can realize the host-guest combination with β-CD, leading to a red shift of another SPR resonant valley, and the maximum wavelength shift is 18.893 nm in the cholesterol concentration range of 0–300 nM. The detection limits of the sensor to glucose and cholesterol are 0.00078 mM and 0.012 nM, respectively. The enhances the practical value of the dual-parameter sensor. Both theory and experiment results verify the feasibility of the “plug-and-play” sensor to measure the dual biomass of glucose and cholesterol with ultra-low detection limit and good selectivity. The proposed method provides a huge research value for the optical fiber sensor in multi-parameter measurement.
•A highly-sensitive and reflective optical fiber SPR biosensor was proposed for dual-parameter measurement.•Glucose and cholesterol concentrations could be simultaneously measured by one sensor.•Au nanoparticles were coated on the sensor to adjust the resonant wavelength and enhance the sensor sensitivity.•The cross-sensitivity between glucose and cholesterol could be neglected by selecting PMBA and β-CD as sensitive materials.•The sensor has an ultra-low detection limit and excellent selectivity for detecting low concentrations of glucose and cholesterol.
Urbanization and industrialization have significant impacts on energy consumption and CO2 emissions, but their relationship varies at different stages of economic development. Taking cognizance of ...heterogeneity and the “ratchet effect,” this paper adopts the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework as a starting point and re-estimates the relationship using different panel date models. The main results are obtained by dynamic panel threshold regression models, which divide a balanced panel dataset of 73 countries over the period of 1971–2010 into four groups according to their annual income levels. The key results are: (1) in the low-income group, urbanization decreases energy consumption but increases CO2 emissions; (2) in the middle-/low-income and high-income groups, industrialization decreases energy consumption but increases CO2 emissions, while urbanization significantly increases both energy consumption and CO2 emissions; (3) for the middle-/high-income group, urbanization does not significantly affect energy consumption, but does hinder the growth of emissions; while industrialization was found to have an insignificant impact on energy consumption and CO2 emissions; (4) from the population perspective, it produces positive effects on energy consumption, and also increases emissions except for the high-income group. These novel methodology and findings reveal that different development strategies of urbanization and industrialization should be pursued depending on the levels of income in a bid to conserve energy and reduce emissions.
We report a 2-family cluster of persons infected with severe acute respiratory syndrome coronavirus 2 in the city of Zhoushan, Zhejiang Province, China, during January 2020. The infections resulted ...from contact with an infected but potentially presymptomatic traveler from the city of Wuhan in Hubei Province.
Low earth orbit (LEO) satellite communications are expected to be incorporated in future wireless networks, in particular 5G and beyond networks, to provide global wireless access with enhanced data ...rates. Massive multiple-input multiple-output (MIMO) techniques, though widely used in terrestrial communication systems, have not been applied to LEO satellite communication systems. In this paper, we propose a massive MIMO transmission scheme with full frequency reuse (FFR) for LEO satellite communication systems and exploit statistical channel state information (sCSI) to address the difficulty of obtaining instantaneous CSI (iCSI) at the transmitter. We first establish the massive MIMO channel model for LEO satellite communications and simplify the transmission designs via performing Doppler and delay compensations at user terminals (UTs). Then, we develop the low-complexity sCSI based downlink (DL) precoder and uplink (UL) receiver in closed-form, aiming to maximize the average signal-to-leakage-plus-noise ratio (ASLNR) and the average signal-to-interference-plus-noise ratio (ASINR), respectively. It is shown that the DL ASLNRs and UL ASINRs of all UTs reach their upper bounds under some channel condition. Motivated by this, we propose a space angle based user grouping (SAUG) algorithm to schedule the served UTs into different groups, where each group of UTs use the same time and frequency resource. The proposed algorithm is asymptotically optimal in the sense that the lower and upper bounds of the achievable rate coincide when the number of satellite antennas or UT groups is sufficiently large. Numerical results demonstrate that the proposed massive MIMO transmission scheme with FFR significantly enhances the data rate of LEO satellite communication systems. Notably, the proposed sCSI based precoder and receiver achieve the similar performance with the iCSI based ones that are often infeasible in practice.
Massive multiple-input multiple-output (M-MIMO) technology is considered to be a key enabling technology for future wireless communication systems. One of the challenges in effectively implementing ...an advanced precoding scheme to a large-scale array antenna is how to reduce the mutual coupling among antenna elements. In this paper, a new concept that is called array-antenna decoupling surface (ADS) for reducing the mutual coupling between antenna elements in a large-scale array antenna is proposed for the first time. An ADS is a thin surface that is composed of a plurality of electrical small metal patches and is placed in front of the array antenna. The partially diffracted waves from the ADS can be controlled to cancel the unwanted coupled waves. Two practical design examples are given to illustrate the design process and considerations, and to demonstrate the usefulness of ADS for the applications of phased array antennas and M-MIMO systems when commonly used precoding schemes are applied. The attractive features of ADS include its applicability to a large-scale array antenna; suitability for a wide range of antenna forms; wide decoupling bandwidth; and simplicity in implementation.
This paper presents a novel technique for decoupling of two closely spaced dual-band antennas using T-stub circuits. A decoupling circuit consists of three T-stub elements, each of which provides the ...required phases and impedances in dual frequency bands independently. A set of general design formulas is derived for determining the electric parameters of required T-stubs. To validate the new decoupling technique, a pair of dual-band inverted-F antennas working in the 2.45- and 5.8-GHz bands and another pair of dual-band monopole antennas working in the 2.4- and 5.2-GHz bands with and without the decoupling circuit are designed, prototyped, and measured. The measured S-parameters correlate with the theoretical designed data very well. With the decoupling circuit, significant improvement in antenna efficiency and data throughput demonstrates that the technique is useful for wireless terminals, where dual-band multiple-input and multiple-output antennas are used.
Proteolysis-targeting chimeras (PROTACs) are heterobifunctional molecules consisting of one ligand that binds to a protein of interest (POI) and another that can recruit an E3 ubiquitin ligase. The ...chemically-induced proximity between the POI and E3 ligase results in ubiquitination and subsequent degradation of the POI by the ubiquitin-proteasome system (UPS). The event-driven mechanism of action (MOA) of PROTACs offers several advantages compared to traditional occupancy-driven small molecule inhibitors, such as a catalytic nature, reduced dosing and dosing frequency, a more potent and longer-lasting effect, an added layer of selectivity to reduce potential toxicity, efficacy in the face of drug-resistance mechanisms, targeting nonenzymatic functions, and expanded target space. Here, we highlight important milestones and briefly discuss lessons learned about targeted protein degradation (TPD) in recent years and conjecture on the efforts still needed to expand the toolbox for PROTAC discovery to ultimately provide promising therapeutics.
This review highlights important milestones in the evolution of PROTACs, briefly discusses recent lessons about targeted protein degradation, and conjectures on the efforts still needed to expand the toolbox for PROTAC discovery.
•Two total factor productivities of China are estimated by super-DEA models.•Investment-driven growth model produces the negative effect on green productivity.•Various structural transformation have ...different impacts on green productivity.
This study investigates the impacts of investment-driven economic growth model, as well as rationalization and upgrading of the industrial structure on green productivity in 30 Chinese provinces over the period 1997–2010. Two total factor productivities (TFP), namely energy adjusted TFP and energy and carbon dioxide emissions adjusted TFP (denoted as TFEE and TFCE respectively), are estimated using super-efficiency DEA models, and used as indices to reflect green productivity performance in China. The main results of the empirical study are as follow: (1) China’s economic growth model does not improve both TFEE and TFCE; (2) the flow of laborers from the primary, secondary, and tertiary industries helps to improve TFEE and TFCE, while capital transformation does not produce the same effect; (3) the structural changes in the manufacturing industry produce negative and positive effects on TFEE and TFCE respectively.
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