The spin-statistics connection is derived in a simple manner under the postulates that (1) the state vectors are only superposed with the plus sign, and (2) not only a common spin quantization axis but a complete quantization frame has to be specified. This means that the orientation of the spin states in the plane normal to the quantization axis has to be specified. Before the state vectors ca...

The spin-statistics connection is derived in a simple manner under the postulates that (1) the state vectors are only superposed with the plus sign, and (2) not only a common spin quantization axis but a complete quantization frame has to be specified. This means that the orientation of the spin states in the plane normal to the quantization axis has to be specified. Before the state vectors ca...

It is well-known that each nonnegative integral flow of a directed graph can be decomposed into a sum of nonnegative graph circuit flows, which cannot be further decomposed into nonnegative integral sub-flows. This is equivalent to saying that indecomposable flows of graphs are those graph circuit flows. Turning from graphs to signed graphs, the indecomposable flows are much richer than that of...

We investigate the positivity of the Euclidean path integral measure for low-energy modes in dense fermionic matter. We show that the sign problem usually associated with fermions is absent if one considers only low-energy degrees of freedom. We describe a method for simulating dense QCD on the lattice and give a proof using rigorous inequalities that the color-flavor locked (CFL) phase is the ...

Recently, cluster methods have been used to solve a variety of sign problems including those that arise in the presence of fermions. In all cases an analytic partial re-summation over a class of configurations in the path integral was necessary. Here the new ideas are illustrated using the example of QCD at a finite density of static quarks. In this limit the sign problem simplifies since the f...

The usual path integral formulation for scalar particles at finite density involves a sign problem, making numerical simulation impractical. We present alternative methods free of this difficulty. We apply these approaches to |φ | 4 theory in 2 + 1 dimensions, presenting preliminary numerical results for physical quantities in the vicinity of the phase transition in the T − µ plane.

Abstract. We study classes of nth order boundary value problems consisting of an equation having a sign-changing nonlinearity f(t, x) together with several different sets of nonhomogeneous multi-point boundary conditions. Criteria are established for the existence of nontrivial solutions, positive solutions, and negative solutions of the problems under consideration. Conditions are determined b...

We study the utility of a complex Langevin ~CL! equation as an alternative for the Monte Carlo ~MC! procedure in the evaluation of expectation values occurring in fermionic many-body problems. We find that a CL approach is natural in cases where nonpositive definite probability measures occur, and remains accurate even when the corresponding MC calculation develops a severe ‘‘sign problem.’’ Wh...

The vital signs are an integral part of clinical methods. In diabetes, determination of plasma glucose can be taken as the fifth vital sign. The sixth vital sign is well being, which can easily be measured by two item questionnaires designed to assess distress, depression and coping skills. This sign is essential for the screening and follow up of persons living with diabetes, as it provides an...