Solving some gauge systems at infinite N

After summarizing briefly some numerical results for four-dimensional supersymmetric SU(2) Yang-Mills quantum mechanics, we review a recent study of systems with an infinite number of colours. We study in detail a particular supersymmetric matrix model which exhibits a phase transition, strong-weak duality, and a rich structure of supersymmetric vacua. In the planar and strong coupling limits, this field theoretical system is equivalent to a one-dimensional XXZ Heisenberg chain and, at the same time, to a gas of $q$-bosons. This not only reveals a hidden supersymmetry in these well-studied models; it also maps the intricate pattern of our supersymmetic vacua into that of the now-popular ground states of the XXZ chain.Comment: 23 pages, 7 figures; lecture given at the XLVI Cracow School of Theoretical Physics; some typos and references correcte

Recent progress in supersymmetric Yang-Mills quantum mechanics in various dimensions

We review the last year progress in understanding supersymmetric SU(2) Yang-Mills quantum mechanics in four and ten space-time dimensions. The four dimensional system is now well under control and the precise spectrum is obtained in all channels. In D=10 some new results are also available.Comment: 19 pages, 4 figures, presented at the Workshop on Random Geometry, Krakow, May 15 - 17, 200

On the SO(9) structure of supersymmetric Yang-Mills quantum mechanics

In ten space-time dimensions the number of Majorana-Weyl fermions is not conserved, not only during the time evolution, but also by rotations. As a consequence the empty Fock state is not rotationally symmetric. We construct explicitly the simplest singlet state which provides the starting point for building up invariant SO(9) subspaces. The state has non-zero fermion number and is a complicated combination of the 1360 elementary, gauge invariant, gluinoless Fock states with twelve fermions. Fermionic structure of higher irreps of SO(9) is also briefly outlined.Comment: 9 page

High energy nucleus-nucleus collisions

Experimental results on high energy nucleus-nucleus interactions are presented. The data are discussed within the framework of standard super-position models and from the point-of-view of the possible formation of new states of matter in heavy ion collisions

Beyond Complex Langevin Equations: a Progress Report

After a short review of one of proposals to avoid complex stochastic processes in Complex Langevin studies, the recent progress in the former is reported. In particular, the new developments allow now to construct positive and normalizable representations for gaussian quantum mechanical, as well as field theoretical, path integrals directly in the Minkowski time. A relation to the idea of thimbles is also discussed.Comment: 7 pages, 2 figures, contribution to the Lattice2018 Symposiu

Large N, Supersymmetry ... and QCD

This paper consists of two (still only vaguely) related parts: in the first, we briefly review work done in the past three years on the ``planar equivalence" between a class of non-supersymmetric theories (including limiting cases of QCD) and their corresponding supersymmetric "parents"; in the second, we present details of a new formulation of planar quantum mechanics and illustrate its effectiveness in an intriguing supersymmetric example.Comment: A contribution to the A. Di Giacomo Festschrift: Physics and Beauty, 21 pages, 8 figure

Quantum systems in a cut Fock space

Standard quantum mechanics is viewed as a limit of a cut system with artificially restricted dimension of a Hilbert space. Exact spectrum of cut momentum and coordinate operators is derived and the limiting transition to the infinite dimensional Hilbert space is studied in detail. The difference between systems with discrete and continuous energy spectra is emphasized. In particular a new scaling law, characteristic for nonlocalized, states is found. Some applications for supersymmetric quantum mechanics are briefly outlined.Comment: 10 page