Some Aspects of Many-Body Problem

Many–Body Aspects of Approach to Equilibrium

In 1956 Mark Kac [5] invented a microscopic, linear model, from which the nonlinear Boltzmann equation describing the evolution of the velocity distribution for a system of colliding particles could be rigorously derived. Consider N particles in one dimension that interact through random collisions. We consider the spatially homogeneous case only, i.e., the case where the particles are uniforml...

Convexity and the quantum many-body problem

We recall some properties of convex functions and, in particular, of the sum of the largest eigenvalues of a Hermitian matrix. From these properties a new estimate of an arbitrary eigenvalue of a sum of Hermitian matrices is derived, which in turn is used to compute an approximate associated spectral projector. These estimates are applied for the first time to explain generic spectral features ...

Some Aspects of the Problem of Fatigue

Ludwig Aschoff pointed out in his lectures on pathology that it is impossible to distinguish histologically between infections and regenerative and reparative inflammation. This means that the organism has few ways, or probably one essential way to act or react in its struggle for life and health. This is true not only for the above mentioned reactions but also for the causes which produce some...

Some Aspects of the Balun Problem

W hy all the mystery surrounding baluns? Here’s some straight talk to dispel the rumors! The balun — to use, or not to use — is one of today’s hottest topics in Amateur Radio. Because certain aspects of the connection between a coaxial feed line and a balanced antenna have been ignored, misunderstanding still exists concerning the function of baluns. Many commercial baluns embody some form of i...

Some Concrete Aspects of Hilbert's 17th Problem