The Feynman-Dyson propagators for neutral particles (locality or non-locality?)

An analog of the $S=1/2$ Feynman-Dyson propagator is presented in the framework of the $S=1$ Weinberg's theory.The basis for this construction is the concept of the Weinberg field as a system of four field functions differing by parity and by dual transformations.Next, we analyze the recent controversy in the definitions of the Feynman-Dyson propagator for the field operator containing the $S=1/2$ self/anti-self charge conjugate states in the papers by D. Ahluwalia et al. and by W. Rodrigues Jr. et al. The solution of this mathematical controversy is obvious. It is related to the necessary doubling of the Fock Space (as in the Barut and Ziino works), thus extending the corresponding Clifford Algebra. However, the logical interrelations of different mathematical foundations with the physical interpretations are not so obvious. Physics should choose only one correct formalism- it is not clear, why two correct mathematical formalisms (which are based on the same postulates) lead to different physical results?

Counter-propagating charge transport in the quantum Hall effect regime

The quantum Hall effect, observed in a two-dimensional (2D) electron gas subjected to a perpendicular magnetic field, imposes a 1D-like chiral, downstream, transport of charge carriers along the sample edges. Although this picture remains valid for electrons and Laughlin’s fractional quasiparticles, it no longer holds for quasiparticles in the so-called hole-conjugate states. These states are expected, when disorder and interactions are weak, to harbor upstream charge modes. However, so far, charge currents were observed to flow exclusively downstream in the quantum Hall regime. Studying the canonical spin-polarized and spin-unpolarized v = 2/3 hole-like states in GaAs-AlGaAs heterostructures, we observed a significant upstream charge current at short propagation distances in the spin unpolarized state.

IMPROVEMENT OF ONE QUANTUM ENCRYPTION SCHEME

Zhou et al. proposed a quantum encryption scheme based on quantum computation in 2006 [N. Zhou et al., Physica A362 (2006) 305]. Each qubit of the ciphertext is constrained to two pairs of conjugate states. So, its implementation is feasible with the existing technology. But it is inefficient since it entails six key bits to encrypt one message bit, and the resulting ciphertext for one message bit consists of three qubits. In addition, its security cannot be directly reduced to the well-known BB84 protocol. In this paper, we improve it using the technique developed in BB84 protocol. The new scheme entails only two key bits to encrypt one message bit. The resulting ciphertext is just composed of two qubits. It saves about a half cost without the loss of security. Moreover, the new scheme is probabilistic instead of deterministic.

Internal hydraulic jumps at T-junctions

This paper presents a theoretical investigation of the occurrence of hydraulic jumps in two-layer systems induced by extraction of fluid from the upper layer. The physical configuration consists of a horizontal main pipe along which air and water flow, and a vertically upward side arm. An hydraulic model based on the momentum principle assuming that the fluids do not mix is developed that leads to at least two possible conjugate states for any given two-layer flow. A method of determining the amount of gas which must be extracted into the side arm for a jump to occur is developed and predictions shown to be in reasonable agreement with observation. Unusually, it is shown that above this critical gas take-off value two possible states remain energetically feasible.