Derivation of phenomenological expressions for transition matrix elements for electron-phonon scattering

In the literature on electron-phonon scatterings very often a phenomenological expression for the transition matrix element is used which was derived in the textbooks of Ashcroft/Mermin and of Czycholl. There are various steps in the derivation of this expression. In the textbooks in part different arguments have been used in these steps, but the final result is the same. In the present paper again slightly different arguments are used which motivate the procedure in a more intuitive way. Furthermore, we generalize the phenomenological expression to describe the dependence of the matrix elements on the spin state of the initial and final electron state

BSAURUS- A Package For Inclusive B-Reconstruction in DELPHI

BSAURUS is a software package for the inclusive reconstruction of B-hadrons in Z-decay events taken by the DELPHI detector at LEP. The BSAURUS goal is to reconstruct B-decays, by making use of as many properties of b-jets as possible, with high efficiency and good purity. This is achieved by exploiting the capabilities of the DELPHI detector to their extreme, applying wherever possible physics knowledge about B production and decays and combining different information sources with modern tools- mainly artificial neural networks. This note provides a reference of how BSAURUS outputs are formed, how to access them within the DELPHI framework, and the physics performance one can expect.Comment: 52 pages, 24 figures, added author Z.

Balanced homodyne detectors in QFT

Within the dipole approximation we describe the interaction of a photodiode with the quantum electric field. The diode is modelled by an electron in a bound state which upon interaction, treated perturbatively in the paper, can get excited to one of the scattering states. We furthermore analyze a balanced homodyne detector (BHD) with a local oscillator (LO) consisting of two photodiodes illuminated by a monochromatic coherent state. We show, that to the leading order the BHD's output measures the expectation value of the quantum electric field, in the state without the LO, restricted to the frequency of the LO. The square of the output measures the two-point function of the quantum field. This shows that the BHDs provide tools for measurements of sub-vacuum (negative) expectation values of the squares quantum fields and thus for test of Quantum Energy Inequality - like bounds, or other QFT effects under the influence of external conditions.Comment: Revised version with minor mistakes remove

Localization of dexamethasone within dendritic core-multishell (CMS) nanoparticles and skin penetration properties studied by multi-frequency electron paramagnetic resonance (EPR) spectroscopy

The skin and especially the stratum corneum (SC) act as a barrier and protect epidermal cells and thus the whole body against xenobiotica of the external environment. Topical skin treatment requires an efficient drug delivery system (DDS). Polymer-based nanocarriers represent novel transport vehicles for dermal application of drugs. In this study dendritic core-multishell (CMS) nanoparticles were investigated as promising candidates. CMS nanoparticles were loaded with a drug (analogue) and were applied to penetration studies of skin. We determined by dual-frequency electron paramagnetic resonance (EPR) how dexamethasone (Dx) labelled with 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PCA) is associated with the CMS. The micro-environment of the drug loaded to CMS nanoparticles was investigated by pulsed high-field EPR at cryogenic temperature, making use of the fact that magnetic parameters (g-, A-matrices, and spin-lattice relaxation time) represent specific probes for the micro-environment. Additionally, the rotational correlation time of spin-labelled Dx was probed by continuous wave EPR at ambient temperature, which provides independent information on the drug environment. Furthermore, the penetration depth of Dx into the stratum corneum of porcine skin after different topical applications was investigated. The location of Dx in the CMS nanoparticles is revealed and the function of CMS as penetration enhancers for topical application is shown

Relational interpretation of the wave function and a possible way around Bell's theorem

The famous ``spooky action at a distance'' in the EPR-szenario is shown to be a local interaction, once entanglement is interpreted as a kind of ``nearest neighbor'' relation among quantum systems. Furthermore, the wave function itself is interpreted as encoding the ``nearest neighbor'' relations between a quantum system and spatial points. This interpretation becomes natural, if we view space and distance in terms of relations among spatial points. Therefore, ``position'' becomes a purely relational concept. This relational picture leads to a new perspective onto the quantum mechanical formalism, where many of the ``weird'' aspects, like the particle-wave duality, the non-locality of entanglement, or the ``mystery'' of the double-slit experiment, disappear. Furthermore, this picture cirumvents the restrictions set by Bell's inequalities, i.e., a possible (realistic) hidden variable theory based on these concepts can be local and at the same time reproduce the results of quantum mechanics.Comment: Accepted for publication in "International Journal of Theoretical Physics

Effective quantum gravity observables and locally covariant QFT

Perturbative algebraic quantum field theory (pAQFT) is a mathematically rigorous framework that allows to construct models of quantum field theories on a general class of Lorentzian manifolds. Recently this idea has been applied also to perturbative quantum gravity, treated as an effective theory. The difficulty was to find the right notion of observables that would in an appropriate sense be diffeomorphism invariant. In this article I will outline a general framework that allows to quantize theories with local symmetries (this includes infinitesimal diffeomorphism transformations) with the use of the BV (Batalin-Vilkovisky) formalism. This approach has been successfully applied to effective quantum gravity in a recent paper by R. Brunetti, K. Fredenhagen and myself. In the same paper we also proved perturbative background independence of the quantized theory, which is going to be discussed in the present work as well.Comment: 16 pages, based on a plenary talk given at the 14th Marcel Grossmann Meeting in Rome (July 2015

Measurement-induced localization of relative degrees of freedom

Published versio

Correlations of observables in chaotic states of macroscopic quantum systems

We study correlations of observables in energy eigenstates of chaotic systems of a large size $N$. We show that the bipartite entanglement of two subsystems is quite strong, whereas macroscopic entanglement of the total system is absent. It is also found that correlations, either quantum or classical, among less than $N/2$ points are quite small. These results imply that chaotic states are stable. Invariance of these properties under local operations is also shown.Comment: 5 pages, 2 figure

Vacuum Structures in Hamiltonian Light-Front Dynamics

Hamiltonian light-front dynamics of quantum fields may provide a useful approach to systematic non-perturbative approximations to quantum field theories. We investigate inequivalent Hilbert-space representations of the light-front field algebra in which the stability group of the light-front is implemented by unitary transformations. The Hilbert space representation of states is generated by the operator algebra from the vacuum state. There is a large class of vacuum states besides the Fock vacuum which meet all the invariance requirements. The light-front Hamiltonian must annihilate the vacuum and have a positive spectrum. We exhibit relations of the Hamiltonian to the nontrivial vacuum structure.Comment: 16 pages, report \# ANL-PHY-7524-TH-93, (Latex

Local Thermal Equilibrium in Quantum Field Theory on Flat and Curved Spacetimes

The existence of local thermal equilibrium (LTE) states for quantum field theory in the sense of Buchholz, Ojima and Roos is discussed in a model-independent setting. It is shown that for spaces of finitely many independent thermal observables there always exist states which are in LTE in any compact region of Minkowski spacetime. Furthermore, LTE states in curved spacetime are discussed and it is observed that the original definition of LTE on curved backgrounds given by Buchholz and Schlemmer needs to be modified. Under an assumption related to certain unboundedness properties of the pointlike thermal observables, existence of states which are in LTE at a given point in curved spacetime is established. The assumption is discussed for the sets of thermal observables for the free scalar field considered by Schlemmer and Verch.Comment: 16 pages, some minor changes and clarifications; section 4 has been shortened as some unnecessary constructions have been remove