1,720,987 research outputs found
Universe as Klein-Gordon Eigenstates
Full text linkWe formulate Friedmann\u27s equations as second-order linear differential equations. This is done using techniques related to the Schwarzian derivative that selects the -times , where is the scale factor. In particular, it turns out that Friedmann\u27s equations are equivalent to the eigenvalue problems which is suggestive of a measurement problem. are space-independent Klein-Gordon operators, depending only on energy density and pressure, and related to the Klein-Gordon Hamilton-Jacobi equations. The \u27s are also independent of the spatial curvature, labeled by , and absorbed in The above pair of equations is the unique possible linear form of Friedmann\u27s equations unless , in which case there are infinitely many pairs of linear equations. Such a uniqueness just selects the conformal time among the \u27s, which is the key to absorb the curvature term. An immediate consequence of the linear form is that it reveals a new symmetry of Friedmann\u27s equations in flat space.10 pages. Typos correcte
NONPERTURBATIVE RENORMALIZATION GROUP EQUATION AND BETA FUNCTION IN N=2 SUSY YANG-MILLS
No full textWe obtain the exact beta function for N = 2 supersymmetric SU Yang-Mills theory and prove the nonperturbative renormalization group equation ∂ΛF = ∂Λ0F×exp[-2τ0τdxβ-1]
Quantum mechanics from general relativity and the quantum Friedmann equation
Full text linkWe demonstrate that the recently introduced linear equation, reformulating the first Friedmann equation, is the first-order WKB expansion of a quantum cosmological equation. This result shows a deeper underlying connection between General Relativity and Quantum Mechanics, pointing towards a unified framework. Solutions of this equation are built in terms of a scale factor encapsulating quantum effects on a free-falling particle. The quantum scale factor reshapes cosmic dynamics, resolving singularities at its vanishing points in several cases of interest. As an explicit example, we consider the radiation-dominated era and show that the quantum equation is dual to the one in Seiberg–Witten formulation, recently applied to black holes, and incorporates resurgence phenomena and complex metrics, as developed by Kontsevich, Segal, and Witten. This links to the invariance of time parametrization under Γ(2) transformations of the dual wave function
NONPERTURBATIVE RELATIONS IN N=2 SUSY YANG-MILLS AND WDVV EQUATION
No full textWe find the nonperturbative relation between , the prepotential F and in N = 2 supersymmetric Yang-Mills theory (SYM) with gauge group SU(3). Nonlinear differential equations for F including the Witten-Dijkgraaf-Verlinde-Verlinde equation are obtained, indicating that N = 2 SYM theories are essentially topological field theories which should be seen as the low-energy limit of some topological string theory. Furthermore, we construct relevant modular invariant quantities, derive canonical relations between the periods, and find the β function in terms of the moduli. In doing this we discuss the uniformization problem for the quantum moduli space
LA VELOCIMETRIA DOPPLER IN RAPPORTO AL CONTROLLO METABOLICO MATERNO IN GRAVIDANZE COMPLICATE DA DIABETE
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
SOLVING N=2 SYM BY REFLECTION SYMMETRY OF QUANTUM VACUA
No full textThe recently rigorously proved nonperturbative relation u=πi(F-a∂aF/2), underlying N=2 supersymmetry Yang-Mills theory with the gauge group SU(2), implies both the reflection symmetries u(τ) ̄=u(-τ ̄) and u(τ+1)=-u(τ) which hold exactly. The relation also implies that τ is the inverse of the uniformizing coordinate u of the moduli space of quantum vacua MSU(2), that is, τ:MSU(2)-->H, where H is the upper half plane. In this context, the above quantum symmetries are the key points to determine MSU(2). It turns out that the functions a(u) and aD(u), which we derive from first principles, actually coincide with the solution proposed by Seiberg and Witten. We also consider some relevant generalizations
NONPERTURBATIVE 2-D GRAVITY, PUNCTURED SPHERES AND THETA VACUA IN STRING THEORIES
No full textWe consider a model of 2D gravity with the coefficient of the Euler characteristic having an imaginary part π/2. This is equivalent to introduce a Θ-vacuum structure in the genus expansion whose effect is to convert the expansion into a series of alternating signs, presumably Borel summable. We show that the specific heat of the model has a physical behaviour. It can be represented nonperturbatively as a series in terms of integrals over moduli spaces of punctured spheres and the sum of the series can be rewritten as a unique integral over a suitable moduli spaces of punctured spheres and the an explicit realization à la Friedan-Shenker of 2D quantum gravity. We conjecture that the expansion in terms of punctures and the genus expansion can be derived using the Duistermaat-Heckman theorem. We briefly analyze expansions in terms of punctured spheres also for multicritical models
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