Search

Preparing the ground state of a given Hamiltonian and estimating its ground energy are important but computationally hard tasks. However, given some additional information, these problems can be solved efficiently on a quantum computer. We assume that an initial state with non-trivial overlap with the ground state can be efficiently prepared, and the spectral gap between the ground energy and the first excited energy is bounded from below. With these assumptions we design an algorithm that prepares the ground state when an upper bound of the ground energy is known, whose runtime has a logarithmic dependence on the inverse error. When such an upper bound is not known, we propose a hybrid quantum-classical algorithm to estimate the ground energy, where the dependence of the number of queries to the initial state on the desired precision is exponentially improved compared to the current state-of-the-art algorithm proposed in [Ge et al. 2019]. These two algorithms can then be combined to prepare a ground state without knowing an upper bound of the ground energy. We also prove that our algorithms reach the complexity lower bounds by applying it to the unstructured search problem and the quantum approximate counting problem.

We present a quantum eigenstate filtering algorithm based on quantum signal processing (QSP) and minimax polynomials. The algorithm allows us to efficiently prepare a target eigenstate of a given Hamiltonian, if we have access to an initial state with non-trivial overlap with the target eigenstate and have a reasonable lower bound for the spectral gap. We apply this algorithm to the quantum linear system problem (QLSP), and present two algorithms based on quantum adiabatic computing (AQC) and quantum Zeno effect respectively. Both algorithms prepare the final solution as a pure state, and achieves the near optimal Oe(dκlog(1/∊)) query complexity for a d-sparse matrix, where κ is the condition number, and ∊ is the desired precision. Neither algorithm uses phase estimation or amplitude amplification.

Density matrix embedding theory (DMET) is a quantum embedding theory for strongly correlated systems. From a computational perspective, one bottleneck in DMET is the optimization of the correlation potential to achieve self-consistency, especially for heterogeneous systems of large size. We propose a new method, called projected DMET (p-DMET), which achieves self-consistency without needing to optimize the correlation potential. We demonstrate the performance of p-DMET on the two-dimensional Hubbard model.

Since the outbreak of the coronavirus pandemic, socio-economic inequalities have become exacerbated and COVID-19 related hate crimes have increased. This paper explores how citizenship education might be reimagined in response to this context, with the vision of rebuilding a more equitable and compassionate society. By using a collective autobiographical writing approach, this study documented six different autobiographical reflexivities of citizenship education scholars who were from different parts of the world: China, South Korea, the Philippines, the United States, Nepal and the United Kingdom. It also observed the way the pandemic played out in the location where they were situated during the research as well as how it played out in their countries of origin, and further, how it affected the civic development in each context. The scholars' range of autobiographical expressions resulted in insights for developing a type of citizenship education, namely, education for active and compassionate citizenship.

We present surprising observations by the NASA Van Allen Probes spacecraft of whistler waves with substantial electric field power at harmonics of the whistler wave fundamental frequency. The wave power at harmonics is due to a nonlinearly steepened whistler electrostatic field that becomes possible in the two-temperature electron plasma due to the whistler wave coupling to the electron-acoustic mode. The simulation and analytical estimates show that the steepening takes a few tens of milliseconds. The hydrodynamic energy cascade to higher frequencies facilitates efficient energy transfer from cyclotron resonant electrons, driving the whistler waves, to lower energy electrons.

A new genus and species of an amphicyonid from the Bose Basin of Guangxi, south China, is short-jawed with relatively bunodont cheek teeth that are characterized by reduction in cusp number. This taxon is the oldest record of an amphicyonid from south Asia and possibly for all of Asia. Despite its antiquity, it is derived in the development of brachygnathy and differs from other early amphicyonids that have shortened faces. Evidently brachygnathy was established in this species without loss of p1-2 or m2-3, which became single-rooted from a primitive double-rooted condition.

OBJECTIVE: This study aimed to investigate the therapeutic effects and underlying mechanisms of Sankudiwan (SKDW) on myocardial ischemia-reperfusion injury (MIRI) in a rat model. MATERIALS AND METHODS: Rats were subjected to MIRI and treated with varying doses of SKDW. The myocardial infarct size, cardiac function, histological changes, apoptosis, and inflammation were assessed using TTC staining, echocardiography, Hematoxylin and Eosin (HE) staining, TUNEL staining, and ELISA assays. We further explored SKDW's influence on cardiomyocyte mitochondria and inflammatory factor expression. Moreover, oxidative stress-related parameters and differentially expressed genes were analyzed using bioinformatics approaches. RESULTS: SKDW significantly reduced myocardial infarct size and improved cardiac function, demonstrating a dose-dependent therapeutic potential. It ameliorated myocardial tissue damage at the histological level, inhibited cardiomyocyte apoptosis, and mitigated inflammatory response. SKDW also enhanced mitochondrial energy metabolism and suppressed the levels of oxidative stress markers. Bioinformatics analysis identified key differentially expressed genes (DEGs), including cbln1, Tgm1, Trh, and Ccl27, possibly mediating the therapeutic effects of SKDW. CONCLUSIONS: SKDW exerts its therapeutic effects on MIRI through the modulation of several genes and pathways related to inflammation, apoptosis, mitochondrial function, and oxidative stress. Our findings provide a scientific basis for the clinical application of SKDW in the treatment of MIRI. [ABSTRACT FROM AUTHOR]