We show that new massless Dirac fermions are generated when a slowly varying periodic potential is applied to graphene. These quasiparticles, generated near the supercell Brillouin zone boundaries with anisotropic group velocity, are different from the original massless Dirac fermions. The quasiparticle wave vector (measured from the new Dirac point), the generalized pseudospin vector, and the ...

The vacuum diagram is calculated at second order for theories with self-interacting massless fields in the framework of finite causal perturbation theory. It is pointed out that the infrared behaviour of the vacuum diagram leads to unstable Fock vacua for QCD or massless QED, but not for quantum gravity. Therefore a radical rearrangement of the physical system must take place for such theories....

The (m2,Lambda) plane of spin s>1 massive fields in (anti-) de Sitter space backgrounds is shown to consist of separate phases, divided by lines of novel "partially massless" gauge theories that successively remove helicities, starting from the lowest, 0 or +/-1/2. The norms of the excluded states flip as the gauge lines are crossed and only the region containing the massive Minkowski theory is...

We study a one-to-one map between massless scalar fields on d+1 dimensional Minkowski (Euclidean) space time and scalar fields on d+1 dimensional De Sitter (Euclidean AdS) space. We solve the Klein-Gordon equation for massless scalar field in terms of initial data on the hypersurface t=0 which is isomorphic to the boundary of dS (AdS) space. By inserting these solutions into the action of massl...

It has been noted for a long time that, in some circumstances, massless neutrinos may be mixed in the leptonic charged current. Conventional neutrino oscillation searches in vacuum are insensitive to this mixing. We discuss the effects of resonant massless-neutrino conversions in the dense medium of a supernova. In particular, we show how the detected ν̄e energy spectra from SN1987a and the supe...

We discuss the spectra of multi-flavor massless QCD2. An approximation in which the Hilbert space is truncated to two currents states is used. We write down a ’t Hooft like equation for the wave function of the two currents states. We solve this equation for the lowest massive state and find an excellent agreement with the DLCQ results. In addition, the ’t Hooft model and the large Nf limit spe...

Spinors are lightlike. How do they combine to make massive particles? We visit the zoo of Lagrangian singularities, or caustics, in spacetime projections from spin spacethe phase space of lightlike, 8spinor flows. We find that the species living there are the elementary particles. Codimension J = (1, 2, 3, 4) phase singularities vortex lines, sheets, tubes, and knots, are classified by the Coxe...

The symmetries of QCD allow for a CP breaking term in the QCD Lagrangian. However, measurements of the neutron dipole moment have demonstrated that the coefficient of this term is very small, if not zero. The unnatural smallness of this coefficient is known as the strong CP problem. A massless up quark has long been proposed as a potential elegant solution to the problem. Without the up quark m...

casimir forces of massive ferrnionic dirac fields are calculated for parallel plates geometry in spatial space with dimension d and imposing bag model boundary conditions. it is shown that in the range of ma>>l where m is mass of fields quanta and a is the separation distance of the plates, it is equal to massive bosonic fields casimir force for each degree of freedom. we argue this equality ex...

The previous studies of the island and double holography mainly focus on codimension-one branes. This paper explores codimension-two brane in AdS/dCFT. is closely related to conical singularity, which very different from brane. We analyze mass spectrum gravitons find that larger tension is, smaller gravitational is. massless mode forbidden by either boundary or normalization conditions. prove f...