Higher Rank Wilson Loops in N = 2* Super-Yang-Mills Theory

The N=2* Super-Yang-Mills theory (SYM*) undergoes an infinite sequence of large-N quantum phase transitions. We compute expectation values of Wilson loops in k-symmetric and antisymmetric representations of the SU(N) gauge group in this theory and show that the same phenomenon that causes the phase transitions at finite coupling leads to a non-analytic dependence of Wilson loops on k/N when the coupling is strictly infinite, thus making the higher-representation Wilson loops ideal holographic probes of the non-trivial phase structure of SYM*.Comment: 33 pages, 6 figures. v2: a new reference adde

Influence of Publication Capacity on Journal Impact Factor for International Open Access Journals from China: Insights from Microeconomic Analysis

The evolving landscape of open access (OA) journal publishing holds significant importance for policymakers and stakeholders who seek to make informed decisions and develop strategies that foster sustainable growth and advancements in open access initiatives within China. This study addressed the shortcomings of the current journal evaluation system and recognized the necessity of researching the elasticity of annual publication capacity (PUB) in relation to the Journal Impact Factor (JIF). By constructing an economic model of elasticity, a comparative analysis of the characteristics and dynamics of international OA journals from China and overseas was conducted. The analysis categorized OA journals based on their respective elasticity values and provided specific recommendations tailored to each category. These recommendations offer valuable insights into the development and growth potential of both OA journals from China and overseas. Moreover, the findings underscore the importance of strategic decision-making to strike a balance between quantity and quality in OA journal management. By comprehending the dynamic nature of elasticity, China can enhance its OA journal landscape, effectively meet the academic demand from domestic researchers, minimize the outflow of OA publications to overseas markets, and fortify its position within the global scholarly community

ALD PROCESSES AND APPLICATIONS TO NANOSTRUCTURED ELECTROCHEMICAL ENERGY STORAGE DEVECES

Next generation Li-ion batteries (LIB) are expected to display high power densities (i.e. high rate performance, or fast energy storage) while maintaining high energy densities and stable cycling performance. The key to fast energy storage is the efficient management of electron conduction, Li diffusion, and Li-ion migration in the electrode systems, which requires tailored material and structural engineering in nanometer scale. Atomic layer deposition (ALD) is a unique technique for nanostructure fabrications due to its precise thickness control, unprecedented conformality, and wide variety of available materials. This research aims at using ALD to fabricate materials, electrodes, and devices for fast electrochemical energy storage. First, we performed a detailed study of ALD V2O5 as a high capacity cathode material, using vanadium tri-isopropoxide (VTOP) precursor with both O3 and H2O as oxidant. The new O3-based process produces polycrystalline films with generally higher storage capacity than the amorphous films resulting from the traditional H2O-based process. We identified the crucial tradeoff between higher gravimetric capacity with thinner films and higher material mass with thicker films. For the thickness regime 10-120 nm, we chose areal energy and power density as a useful metric for this tradeoff and found that it is optimized at 60 nm for the O3-VTOP ALD V2O5 films. In order to increase material loading on fixed footprint area, we explored various 3-dimentional (3D) substrates. In the first example, we used multiwall carbon nanotube (MWCNT) sponge as scaffold and current collector. The core/shell MWCNT/V2O5 sponge delivers a stable high areal capacity of 816 μAh/cm2 for 2 Li/V2O5 voltage range (4.0-2.1 V) at 1C rate (nC means charge/discharge in 1/n hour), 450 times that of a planar V2O5 thin film cathode. Due to low density of MWCNT and thin V2O5 layer, the sponge cathode also delivers high gravimetric power density in device level that shows 5X higher power density than commercial LIBs. In the other example, Li-storage paper cathodes, functionalized of conductivity from CNT and Li-storage capability from V2O5¬, presented remarkably high rate performance due to the hierarchical porosity in paper for Li+ migration. The specific capacity of V2O5 is as high as 410 mAh/g at 1C rate, and retained 116 mAh/g at high rate of 100C. We found V2O5 capacities decreased by about 30% at high rates of 5C-100C after blocking the mesopores in cellulose fiber, which serves to be the first confirmative evidence of the critical role of mesoporosity in paper fibers for high-rate electrochemical devices. Finally, we made high density well-aligned nanoporous electrodes (2 billion/cm2) using anodic alumina template (AAO). ALD materials were deposited into the nanopores sequentially - Ru or TiN for current collection, and V2O5 for Li-storage. Ru metal by ALD shows high conductivity and conformality, and serves best as the current collector for V2O5. The capacity of V2O5 reaches about 88% of its theoretic value at high rate of 50C. Such electrodes can be cycled for 1000 times with 78% capacity retention

N=2* Super-Yang-Mills Theory at Strong Coupling

The planar N=2* Super-Yang-Mills (SYM) theory is solved at large 't Hooft coupling using localization on S(4). The solution permits detailed investigation of the resonance phenomena responsible for quantum phase transitions in infinite volume, and leads to quantitative predictions for the semiclassical string dual of the N=2* theory.Comment: 34 pages, 9 figures; v2: the name of one author change

Notes on a non-thermal fluctuation-dissipation relation in quantum Brownian motion

We review how unitarity and stationarity in the Schwinger-Keldysh formalism naturally lead to a (quantum) generalized fluctuation-dissipation relation (gFDR) that works beyond thermal equilibrium. Non-Gaussian loop corrections are also presented. Additionally, we illustrate the application of this gFDR in various scenarios related to quantum Brownian motion and the generalized Langevin equation.Comment: 24 pages, 9 figure