Quantumness of correlations and Maxwell's demons in elementary scattering processes—Energetic consequences

The interactions between physical systems generally lead to the formation of correlations. In this paper we consider the phenomena of entanglement and "quantumness of correlations", such as quantum discord, with particular emphasis on their energetic consequences for the participating systems. We describe a number of theoretical models that are commonly employed in this context, highlighting the general character of one of their most intriguing results: In contradiction to conventional expectations, erasure (decay, consumption) of quantum correlations may be a source of work, i.e. may have "negative energetic costs". We report experimental evidence of this surprising effect obtained within the framework of an elementary scattering experiment, namely ultrafast neutron Compton scattering from normal-state liquid 4He. The general theory of quantumness of correlations provides a natural way of interpreting the reported results, which stand in blatant contrast to the conventional theory of scattering, where neutron-atom-environment quantum correlations and decoherence play no role. Moreover, they provide a new operational meaning of discord and related measures of quantumness

Weak Values and Quantum Information in Scattering Physics — New Theoretical and Experimental Effects

Weak Values (WV) and Two-State-Vector Formalism (TSVF) provide novel insights in various quantum physical and technological fields. In the first part of the paper we consider a new quantum effect of scattering accompanying an elementary collision of two quantum systems A and B, in which the latter interacts with a quantum environment. In clear contrast to a classical environment, the quantum case can exhibit counter-intuitive effects of momentum- and energy-transfer which contradict conventional expectations. Experimental evidence of a new effect—deficit of momentum transfer (equivalently: reduced effective mass) in a neutron-atom collision—is presented and theoretically interpreted. Here, non-relativistic incoherent inelastic neutron scattering (INS) is applied. INS on single H2 molecules confined in multi-walled carbon nanotube channels has been experimentally investigated. Interpreted within conventional theory, the results reveal a counter-intuitive reduced effective mass of the recoiling H2 molecule, i.e. M = 0.64 a.m.u. (atomic mass units). In contrast, this finding has a simple qualitative interpretation within WV and TSVF theory. In the second part of the paper we report on current experimental and theoretical investigations in the field of X-ray diffraction (XRD), which belongs to coherent scattering. Preliminary XRD results from cubic crystalline materials show a surprising variation of the measured lattice parameter (usually called “lattice constant”) with momentum transfer. A first theoretical model of the effect in the light of the new theory is presented. These findings give further evidence for the broad character and significance of the novel WV and TSVF theory

Weak measurement and weak values — New insights and effects in reflectivity and scattering processes

Recently, the notions of Weak Measurement (WM), Weak Value (WV) and Two-State-Vector Formalism (TSVF), firstly introduced by Aharonov and collaborators, have extended the theoretical frame of standard quantum mechanics, thus providing a quantum-theoretical formalism for extracting new information from a system in the limit of small disturbance to its state. Here we provide an application to the case of two-body scattering with one body weakly interacting with its environment — e.g. a neutron being scattered from a H2 molecule physisorbed in a carbon nanotube. In particular, we make contact with the field of incoherent inelastic neutron scattering from condensed systems. We provide a physically compelling prediction of a new quantum effect — a momentum transfer deficit; or equivalently, an enhanced energy transfer; or an apparent reduction of the mass of the struck particle. E.g., when a neutron collides with a H2 molecule in a C-nanotube and excites its translational motion along the nanotube, it apparently exchanges energy and momentum with a fictitious particle with mass of 0.64 atomic mass units. Experimental results are shown and discussed in the new theoretical frame. The effect under consideration has no conventional interpretation, thus also supporting the novelty of the quantum theoretical framework of WV and TVSF. Some speculative remarks about possible applications being of technological interest (fuel cells and hydrogen storage; Li+ batteries; information and communication technology) are shortly mentioned

A Statistical Description of Molecular Dynamical Processes in Liquids. Application to FIR Absorption Spectroscopy

The basic physical concepts concerning the derivation and validity of the generalized fluctuation-dissipation theorem (FDT) as revealed in an earlier paper11 are discussed. It is shown that dissipation of irradiation within the framework of Kubo\u27s linear response theory is mainly due (i) to the short-time behavior of the coupling operator of a system with the irradiation field, (ii) to the spontaneous fluctuations concerning the statistical operator in the microscopic time scale, and (iii) to the explicit introduction of the coupling of the systems with the thermal bath in Kubo\u27s formalism, as proposed by van Vliet. As a result, the statistical operator becomes time dependent in the shorttime range. Within Kubo\u27s microscopic theory of irreversible processes the generalized FDT also delivers a microscopic interpretation of Prigogine\u27s theorem of minimum entropy production (TMEP)

Partial Wave Analysis of Scattering with Nonlocal Aharonov-Bohm Effect and Anomalous Cross Section induced by Quantum Interference

Partial wave theory of a three dmensional scattering problem for an arbitray short range potential and a nonlocal Aharonov-Bohm magnetic flux is established. The scattering process of a ``hard shere'' like potential and the magnetic flux is examined. An anomalous total cross section is revealed at the specific quantized magnetic flux at low energy which helps explain the composite fermion and boson model in the fractional quantum Hall effect. Since the nonlocal quantum interference of magnetic flux on the charged particles is universal, the nonlocal effect is expected to appear in quite general potential system and will be useful in understanding some other phenomena in mesoscopic phyiscs.Comment: 6 figure

Multifractal characterisation of length sequences of coding and noncoding segments in a complete genome

The coding and noncoding length sequences constructed from a complete genome are characterised by multifractal analysis. The dimension spectrum $D_{q}$ and its derivative, the 'analogous' specific heat $C_{q}$, are calculated for the coding and noncoding length sequences of bacteria, where $q$ is the moment order of the partition sum of the sequences. From the shape of the $$ and $C_{q}$ curves, it is seen that there exists a clear difference between the coding/noncoding length sequences of all organisms considered and a completely random sequence. The complexity of noncoding length sequences is higher than that of coding length sequences for bacteria. Almost all $D_{q}$ curves for coding length sequences are flat, so their multifractality is small whereas almost all $D_{q}$ curves for noncoding length sequences are multifractal-like. We propose to characterise the bacteria according to the types of the $C_{q}$ curves of their noncoding length sequences.Comment: 15 pages with 5 figures, Latex, Accepted for publication in Physica

Advanced tools and concepts for quantum cognition: A tutorial

This tutorial is intended to provide an introduction to some advanced tools and concepts needed to construct more realistic quantum models of cognition and decision. The aim is to cover, in a format suitable for researchers with some limited exposure to quantum models of cognition, the ideas of density matrices, POVM type measurements and open system dynamics. The central theme we explore is how we might introduce noise into our quantum models, and the effect this has on model behavior. These important ideas are likely to be very useful for constructing more realistic cognitive models, but they are generally not covered by introductory accounts of quantum theory. We hope that this tutorial will help to introduce these tools to other researchers interested in constructing quantum models of cognition