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A new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge is presented and solved for the static gluon and ghost propagators under the assumption of ghost dominance. The results are compared to those obtained in the variational approach.
We review properties and lattice evidence in support of the recently proposed temporal-gauge Yang-Mills vacuum wave functional in 2+1 dimensions.
A general method for treating non-Gaussian wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang-Mills theory in Coulomb gauge in order to include a three-gluon kernel in the exponential of the vacuum wave functional. The three-gluon vertex is calculated using the propagators found in the variational approach with a Gaussian trial wave functional as input.
The exact solution of the Dirac equation in the external non-abelian SU(N) gauge field, which is governed by the Yang-Mills equations and is in the form of a plane wave on the light cone, is obtained.
We describe the generalization of the recently derived solutions of D= 2 supersymmetric Yang-Mills quantum mechanics with SU(3) gauge group to the generic case of SU(N) gauge group. We discuss the spectra and eigensolutions in bosonic as well as fermionic sectors.
We provide arguments why the loop expansion of the pressure in the effective theory for the deconfining phase of SU(2) Yang-Mills thermodynamics is likely to terminate at a finite order despite the fact that the effective gauge coupling is large (e{>=}{radical}(8){pi}). Each order l of the expansion measures the lth power of the fraction of a typical residual action of the quantum fluctuation in one loop S{sub l} and h. Here S{sub l} rapidly decreases with l. This is demonstrated by a computation of irreducible 2-loop and 3-loop diagrams which correct the pressure of free quasiparticles radiatively. In fact, at the three-loop level, one diagram vanishes identically. By benchmarking with known 2-loop results we show that the Monte-Carlo method used to compute on the 3-loop level is reliable.
We discuss the constraints on energy-momentum transfers in local vertices in the effective theory for the deconfining phase of SU(2) Yang-Mills thermodynamics. Subsequently, we apply these constraints to the computation of the polarization tensor of the massless mode on the one-loop level. The resulting gap equation for the sought-after screening function is solved numerically. We discuss and interpret our results.
We derive an a useful priori estimate for the thermal ground state of deconfining phase of SU(2) Yang-Mills thermodynamics in four-dimensional, flat spacetime and discuss its implications. Upon a selfconsistent spatial coarse-graining over noninteracting, trivial-holonomy (BPS saturated)(anti)calorons of unit topological charge modulus an inert, adjoint scalar field |{phi}| and an effective pure-gauge configuration a{sub {mu}}{sup gs} emerge. The modulus |{phi}|>0 defines the maximal resolution in the coarse-grained theory and induces dynamical gauge-symmetry breaking. Thanks to perturbative renormalizability and the fact that |{phi}| can not absorb or emit energy-momentum the effective action is local and simple. The temperature dependence of the effective coupling is a consequence of thermodynamical consistency and describes the Coulomb screening of a static test charge due to short-lived monopole-antimonopole pairs. The latter occur unresolvably as small-holonomy excitations of (anti)calorons by the absorption of propagating fundamental gauge fields.
We evaluate analytically the Witten index of D= 2 supersymmetric Yang-Mills quantum mechanics. We rederive a known result for the SU(2) gauge group and generalize it to any SU(N) gauge group.
I give a broad review of novel phenomena discovered in certain Yang-Mills theories: non-Abelian strings and confined monopoles. Then I explain how these phenomena allow one to study strong dynamics of gauge theories in four dimensions from two-dimensional models emerging on the string world sheet.
We discuss the postulate that the U(1) gauge group describing photon propagation results from a dynamically broken SU(2) gauge theory. In the context of Yang-Mills thermodynamics such a symmetry breaking occurs via the non-trivial ground state. As a result of the interaction with the quasi particles of the theory the photon acquires an effective, temperature and momentum dependent, mass. We explain how this leads to modified black body spectra at temperatures of about 5 K. Furthermore, we discuss the properties and effects of an emergent longitudinal polarization.
Calorons and plane waves within and in between them collectively give rise to a thermal ground state. The latter provides a homgeneous energy density and a negative pressure, and it induces quasiparticle masses to part of the propagating spectrum of deconfining SU(2) Yang-Mills thermodynamics (dynamical gauge-symmetry breaking). In the present talk we discuss the role of a single caloron in inducing effective local vertices, characterized by powers of h, mediating the interaction of plane waves which propagate over large distances. The constraints on momentum transfers through effective 4-vertices are revisited.
According to the Big Bang Theory as we go back in time the Universe becomes progressively hotter and denser. This leads us to believe that the early Universe was filled with hot plasma of elementary particles. Among many questions concerning this phase of history of the Universe there are questions of existence and fate of magnetic monopoles and primordial black holes. Static solution of Einstein-Yang-Mills system may be used as a toy model for such a black hole. Using methods of field theory we will show that its existence and regularity depend crucially on the presence of fermions around it.
The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.
We analyse the constraint structure of the topologically massive Yang-Mills theory in instant-form and null-plane dynamics via the Hamilton-Jacobi formalism. The complete set of hamiltonians that generates the dynamics of the system is obtained from the Frobenius’ integrability conditions, as well as its characteristic equations. As generators of canonical transformations, the hamiltonians are naturally linked to the generator of Lagrangian gauge transformations.
High quality superconducting nanowires were fabricated from ultrathin MgB{sub 2} films by a focused ion beam milling technique. The precursor MgB{sub 2} films in 10 nm thick were grown on MgO substrates by using a hybrid physical-chemical vapor deposition method. The nanowires, in widths of about 300-600 nm and lengths of 1 or 10 μm, showed high superconducting critical temperatures (T{sub c}’s) above 34 K and narrow superconducting transition widths (ΔT{sub c}’s) of 1-3 K. The superconducting critical current density J{sub c} of the nanowires was above 5 × 10{sup 7} A/cm{sup 2} at 20 K. The high T{sub c}, narrow ΔT{sub c}, and high J{sub c} of the nanowires offered the possibility of making MgB{sub 2}-based nano-devices such as hot-electron bolometers and superconducting nanowire single-photon detectors with high operating temperatures at 15-20 K.
Nanosized Co{sub 0.3}Zn{sub 0.7}Fe{sub 2}O{sub 4} having average particle size ∼20 nm has been synthesized by mechanochemical method. The results of dc magnetic and Mössbaeur studies suggest that the sample is ferrimagnetic in nature and shows superparamagnetic behavior above 230K. Magnetic ordering in the sample evolves gradually upon cooling the system below blocking temperature. Moreover, the sample exhibits enhancement of magnetic order and ordering temperature with respect to its counterpart synthesized by chemical routes mainly due to increase of stress anisotropy induced by high energy ball milling. We have shown that maintaining suitable cation distribution helps in enhancement of magnetization by reducing the adverse effect of spin canting.
The structural and magnetic properties of as-melted and high energy ball milled alloy samples have been studied by X-ray diffraction, DC magnetization and electronic structure calculations by means of density functional theory. The observed properties are compared to that of the bulk sample. There is a very good enhancement of saturation magnetization and coercivity in the nano-sized samples as compared to bulk which is explained in terms of structural disordering and size effect.