Coordinate representation for non Hermitian position and momentum operators

In this paper we undertake an analysis of the eigenstates of two non self-adjoint operators $\hat q$ and $\hat p$ similar, in a suitable sense, to the self-adjoint position and momentum operators $\hat q_0$ and $\hat p_0$ usually adopted in ordinary quantum mechanics. In particular we discuss conditions for these eigenstates to be {\em biorthogonal distributions}, and we discuss few of their properties. We illustrate our results with two examples, one in which the similarity map between the self-adjoint and the non self-adjoint is bounded, with bounded inverse, and the other in which this is not true. We also briefly propose an alternative strategy to deal with $\hat q$ and $\hat p$, based on the so-called {\em quasi *-algebras}.Comment: Accepted in Proceedings of the Royal Society

An interoperable ICT tool for asset and maintenance management -Advances in research –

Asset and maintenance management needs to store and use much information about the behaviour over time of different building materials, products and components. Service life planning and data capitalization from facility management are only the first steps for an efficient asset management because it is necessary to develop specific ICT tools for life cycle data use and sharing. Managing information related with actual maintenance works and inspection activity (condition assessment) allow handling Building Information Systems and this is fundamental in order to fit the reliability and service life evaluations for maintenance planning. For this reason, an ongoing research activity is developing some methods and tools for Service Life Planning and Management, which can be easily integrated by maintenance data to be used during planning, design, facility and maintenance activities. The aim is to develop an interoperable Life Cycle Management System (LCMS) platform where this kind of data are available and where different stakeholders can store and share information about building and constructed assets. The interoperable LCMS platform can be then used on actual maintenance works management to demonstrate the benefit as for economic (Life Cycle Costs) and environmental achievements (Life Cycle Assessment). This operation has been done according to the international standard for service life planning of building and constructed asset procedures ISO 15686, in particular in conformity with the fifth part on Life-cycle Costing, which allows a cost analysis of the entire building life cycle (maintenance included). Eventually, this ICT-tool is being developed using the standard IFC (Industrial Foundation Classes) of IAI (International Alliance for Interoperability) to define Building Information Models (BIM). In particular, interoperability will be guarantee by sharing file .ifcxml and therefore using eXtensible Mark-up Language (XML). Service life data, maintenance information, costs and each parameter for sustainability have in fact to be matched with Building Information Models attributes, upgrading BIM objects themselves in case of lack of some attributes. This database will be accessible online from a web platform, which is thought to become an interactive footbridge among different stakeholders. As the quantity of collected information will be huge, there are different views of the database according to the stakeholder profile: the aim is to facilitate its use, filtering only useful data for the considered stakeholder, but leaving the possibility to search, visualize and, possibly, modify any other information of the database. Hereafter the advances in research to structure this database and to enhance existing methods and tools for Life Cycle management are described

Van der Waals and resonance interactions between accelerated atoms in vacuum and the Unruh effect

We discuss different physical effects related to the uniform acceleration of atoms in vacuum, in the framework of quantum electrodynamics. We first investigate the van der Waals/Casimir-Polder dispersion and resonance interactions between two uniformly accelerated atoms in vacuum. We show that the atomic acceleration significantly affects the van der Waals force, yielding a different scaling of the interaction with the interatomic distance and an explicit time dependence of the interaction energy. We argue how these results could allow for an indirect detection of the Unruh effect through dispersion interactions between atoms. We then consider the resonance interaction between two accelerated atoms, prepared in a correlated Bell-type state, and interacting with the electromagnetic field in the vacuum state, separating vacuum fluctuations and radiation reaction contributions, both in the free-space and in the presence of a perfectly reflecting plate. We show that nonthermal effects of acceleration manifest in the resonance interaction, yielding a change of the distance dependence of the resonance interaction energy. This suggests that the equivalence between temperature and acceleration does not apply to all radiative properties of accelerated atoms. To further explore this aspect, we evaluate the resonance interaction between two atoms in non inertial motion in the coaccelerated (Rindler) frame and show that in this case the assumption of an Unruh temperature for the field is not required for a complete equivalence of locally inertial and coaccelerated points of views.Comment: 8 pages, Proceedings of the Eighth International Workshop DICE 2016 Spacetime - Matter - Quantum Mechanic

Constraints on anomalous gauge couplings from present LEP1 and future LEP2, BNL data

We analyze, in a rather general model where anomalous triple gauge couplings are present, the visible effects in R$_b$ (measured at LEP1), in W pair production (to be measured at LEP2) and in the muon anomalous magnetic moment (to be measured at BNL). From the combination of the three experiments a remarkable improvement on the pure LEP2 constraints is obtained.Comment: 10 pages and 6 figures. e-mail: [email protected]

The Hadronic Contribution to the Muon g−2g-2 from Hadron Production in Initial State Radiation Events at the e+e−e^+ e^- Collider DAΦ\PhiNE

A relevant reduction of the theoretical uncertainty on the muon anomalous magnetic moment, dominated by the error on the leading hadronic contribution $a^{\rm h}_\mu$, would come from a new precise measurement of the cross section of $e^+e^-$ annihilation into hadrons ($\sigma_h$) below 1~GeV. An experimental approach to the evaluation of the dispersion integral defining $a^{\rm h}_\mu$ is proposed here as an alternative to the conventional method based on the interpolation of different measurements of $\sigma_h$ performed with a center of mass energy scan. The wide occurrence of hadron production, at variable $q^2$, in the initial state radiation (ISR) events at the high luminosity $\phi-$factory DA$\Phi$NE suggests to redefine the dispersion integral in terms of the differential cross section for $e^+e^-\rightarrow hadrons + \gamma_{\rm ISR}$. The feasibility of such measurement, which can be performed without the need of dedicated run conditions and with the benefit of the full luminosity of the machine, is discussed. The required precision is shown to be easily achieved thanks to the resolutions and performances of the KLOE detector

Field fluctuations near a conducting plate and Casimir-Polder forces in the presence of boundary conditions

We consider vacuum fluctuations of the quantum electromagnetic field in the presence of an infinite and perfectly conducting plate. We evaluate how the change of vacuum fluctuations due to the plate modifies the Casimir-Polder potential between two atoms placed near the plate. We use two different methods to evaluate the Casimir-Polder potential in the presence of the plate. They also give new insights on the role of boundary conditions in the Casimir-Polder interatomic potential, as well as indications for possible generalizations to more complicated boundary conditions.Comment: 10 page

Photonic polarization gears for ultra-sensitive angular measurements

Quantum metrology bears a great promise in enhancing measurement precision, but is unlikely to become practical in the near future. Its concepts can nevertheless inspire classical or hybrid methods of immediate value. Here, we demonstrate NOON-like photonic states of m quanta of angular momentum up to m=100, in a setup that acts as a "photonic gear", converting, for each photon, a mechanical rotation of an angle {\theta} into an amplified rotation of the optical polarization by m{\theta}, corresponding to a "super-resolving" Malus' law. We show that this effect leads to single-photon angular measurements with the same precision of polarization-only quantum strategies with m photons, but robust to photon losses. Moreover, we combine the gear effect with the quantum enhancement due to entanglement, thus exploiting the advantages of both approaches. The high "gear ratio" m boosts the current state-of-the-art of optical non-contact angular measurements by almost two orders of magnitude.Comment: 10 pages, 4 figures, + supplementary information (10 pages, 3 figures