Anisotropic nonlinear elastic properties of an icosahedral quasicrystal

We show that the nonlinear behavior of transverse acoustic waves can reveal the anisotropic structure of an icosahedral quasicrystal, at the macroscopic level. We report experiments performed in i-Al-Pd-Mn. We observe that a primary transverse acoustic wave can generate a second harmonic transverse acoustic wave. We also observe a specific relation between the polarization directions of those waves. These observations are manifestations on a macroscopic scale of the long-range order in quasicrystals.     

Incompatibility of macroscopic local realism with quantum mechanics in measurements with macroscopic uncertainties

We show that quantum mechanics predicts a contradiction with local hidden variable theories for photon number measurements which have limited resolving power, to the point of imposing an uncertainty in the photon number result which is macroscopic in absolute terms. We show how this can be interpreted as a failure of a new premise, macroscopic local realism.     

Chiral vortical effect generated by chiral anomaly in vortex-skyrmions

We discuss the type of the general macroscopic parity-violating effects, when there is the current along the vortex, which is concentrated in the vortex core. We consider vortices in chiral superfluids with Weyl points. In the vortex core, the positions of the Weyl points form the skyrmion structure. We show that the mass current concentrated in such a core is provided by the spectral flow through the Weyl points according to the Adler–Bell–Jackiw equation for chiral anomaly.     

Influence of the substrate on negative index fishnet metamaterials

We analyze numerically the influence of the dielectric substrate on the optical response and effective macroscopic parameters of fishnet metamaterials. We show that the substrate can suppress the region of the negative refractive index due to the weakening of the gap plasmon associated with the magnetic resonance of the structure. We also demonstrate that the effect of substrate vanishes when the number of the functional layers increases.     

Electrodynamical treatment of the electron-hole long-range exchange interaction in semiconductor nanocrystals

We show that the contribution to the fine structure of the ground exciton level in a semiconductor nanocrystal due to the long-range part of the electron-hole exchange interaction can be equivalently described as arising from the mechanical exciton interaction with the exciton-induced macroscopic longitudinal electric field. Particular cases of nanocrystals with cubic and wurtzite crystal lattice in the strong confinement regime are studied taking into account the complex structure of the valence band. A simplified model accounting for the exciton ground-level splitting and exploiting an effective local scalar susceptibility is established.     

Superconductivity-induced macroscopic resonant tunneling

We show analytically and by numerical simulations that the conductance through pi-biased chaotic Josephson junctions is enhanced by several orders of magnitude in the short-wavelength regime. We identify the mechanism behind this effect as macroscopic resonant tunneling through a macroscopic number of low-energy quasidegenerate Andreev levels.     

Quantum teleportation through an entangled state composed of displaced vacuum and single-photon states

We study a teleportation protocol of an unknown macroscopic qubit by means of a quantum channel composed of the displaced vacuum and single-photon states. The scheme is based on linear optical devices such as a beam splitter and photon number resolving detectors. A method based on conditional measurement is used to generate both the macroscopic qubit and entangled state composed from displaced vacuum and single-photon states. We show that such a qubit has both macroscopic and microscopic properties. In particular, we investigate a quantum teleportation protocol from a macroscopic object to a microscopic state. The text was submitted by the author in English.     

Superfluid 4He quantum interference grating

We report the first observation of quantum interference from a grating structure consisting of four weak link junctions in superfluid 4He. We find that an interference grating can be implemented successfully in a superfluid matter wave interferometer to enhance its sensitivity while trading away some of its dynamic range. We also show that this type of device can be used to measure absolute quantum mechanical phase differences. The results demonstrate the robust nature of superfluid phase coherence arising from quantum mechanics on a macroscopic scale.     

Quantum degeneracy of microcavity polaritons

We investigate experimentally one of the main features of a quantum fluid constituted by exciton polaritons in a semiconductor microcavity, that is, quantum degeneracy of a macroscopic fraction of the particles. We show that resonant pumping allows us to create a macroscopic population of polaritons in one quantum state. Furthermore, we demonstrate that parametric polariton scattering results in the transfer of a macroscopic population of polariton from one single quantum state into another one. Finally, we briefly outline a simple method which provides direct evidence of the first-order spatial coherence of the transferred population.     

Conductivity tensor of striped quantum hall phases

We study the transport properties of pinned striped quantum Hall phases. We show that, under quite general assumptions, the macroscopic conductivity tensor satisfies a semicircle law. In particular, this result is valid for both smectic and nematic stripe phases, independent of the presence of topological and orientational defects such as dislocations and grain boundaries. As a special case, our results explain the experimental validity of a product rule for the dissipative part of the resistivity tensor, which was previously derived by MacDonald and Fisher (cond-mat/9907278) for a perfect stripe structure.     

The Violation of Bell Inequalities in the Macroworld

We show that Bell inequalities can be violated in the macroscopic world. The macroworld violation is illustrated using an example involving connected vessels of water. We show that whether the violation of inequalities occurs in the microworld or the macroworld, it is the identification of nonidentical events that plays a crucial role. Specifically, we prove that if nonidentical events are consistently differentiated, Bell-type Pitowsky inequalities are no longer violated, even for Bohm's example of two entangled spin 1/2 quantum particles. We show how Bell inequalities can be violated in cognition, specifically in the relationship between abstract concepts and specific instances of these concepts. This supports the hypothesis that genuine quantum structure exists in the mind. We introduce a model where the amount of nonlocality and the degree of quantum uncertainty are parameterized, and demonstrate that increasing nonlocality increases the degree of violation, while increasing quantum uncertainty decreases the degree of violation.     

The collapse and revival of Bell-nonlocality of two macroscopic fields interacting with resonant atoms

We investigate the nonlocality dynamics of two initially entangled macroscopic fields each interacting with a resonant two-level atom. The nonlocality of macroscopic field is characterized by the extent to which the Bell Clauser-Horne-Shimony-Holt (CHSH)'s inequality for continuous-variable states is violated. We show that the collapse and revival of the Bell-nonlocality are similar to the collapse and revival of the atomic population inversion of the Jaynes-Cummings model (JCM).     

Carbon nanotube mats and fibers with irradiation-improved mechanical characteristics: a theoretical model

We employ a theoretical model to calculate mechanical characteristics of macroscopic mats and fibers of single-walled carbon nanotubes. We further investigate irradiation-induced covalent bonds between nanotubes and their effects on the tensile strength of nanotube mats and fibers. We show that the stiffness and strength of the mats can be increased at least by an order of magnitude, and thus small-dose irradiation with energetic particles is a promising tool for making macroscopic nanotube materials with excellent mechanical characteristics.     

Quantum structures due to fluctuations of the measurement situation

We analyze the meaning of the nonclassical aspects of quantum structures. We proceed by introducing a simple mechanistic macroscopic experimental situation that gives rise to quantum-like structures. We use this situation as a guiding example for our attempts to explain the origin of the nonclassical aspects of quantum structures. We see that the quantum probabilities can be introduced as a consequence of the presence of fluctuations on the experimental apparatuses, and show that the full quantum structure can be obtained in this way. We define the classical limit as the physical situation that arises when the fluctuations on the experiment apparatuses disappear. In the limit case we come to a classical structure, but in between we find structures that are neither quantum nor classical. In this sense, our approach not only gives an explanation for the nonclassical structure of quantum theory, but also makes it possible to define and study the structure describing the intermediate new situations. By investigating how the nonlocal quantum behavior disappears during the limiting process, we can explain theapparentlocality of the classical macroscopic world. We come to the conclusion that quantum structures are the ordinary structures of reality, and that our difficulties of becoming aware of this fact are due to prescientific prejudices, some of which we point out.     

Quantifying and Interpreting Connection Strength in Macro- and Microscopic Systems: Lessons from Bell’s Approach

Bell inequalities were created with the goal of improving the understanding of foundational questions in quantum mechanics. To this end, they are typically applied to measurement results generated from entangled systems of particles. They can, however, also be used as a statistical tool for macroscopic systems, where they can describe the connection strength between two components of a system under a causal model. We show that, in principle, data from macroscopic observations analyzed with Bell’ s approach can invalidate certain causal models. To illustrate this use, we describe a macroscopic game setting, without a quantum mechanical measurement process, and analyze it using the framework of Bell experiments. In the macroscopic game, violations of the inequalities can be created by cheating with classically defined strategies. In the physical context, the meaning of violations is less clear and is still vigorously debated. We discuss two measures for optimal strategies to generate a given statistic that violates the inequalities. We show their mathematical equivalence and how they can be computed from CHSH-quantities alone, if non-signaling applies. As a macroscopic example from the financial world, we show how the unfair use of insider knowledge could be picked up using Bell statistics. Finally, in the discussion of realist interpretations of quantum mechanical Bell experiments, cheating strategies are often expressed through the ideas of free choice and locality. In this regard, violations of free choice and locality can be interpreted as two sides of the same coin, which underscores the view that the meaning these terms are given in Bell’s approach should not be confused with their everyday use. In general, we conclude that Bell’s approach also carries lessons for understanding macroscopic systems of which the connectedness conforms to different causal structures.     

Complete condensation in a zero range process on scale-free networks

We study a zero range process on scale-free networks in order to investigate how network structure influences particle dynamics. The zero range process is defined with the rate p(n) = n(delta) at which particles hop out of nodes with n particles. We show analytically that a complete condensation occurs when delta < or = delta(c) triple bond 1/(gamma-1) where gamma is the degree distribution exponent of the underlying networks. In the complete condensation, those nodes whose degree is higher than a threshold are occupied by macroscopic numbers of particles, while the other nodes are occupied by negligible numbers of particles. We also show numerically that the relaxation time follows a power-law scaling tau approximately L(z) with the network size L and a dynamic exponent z in the condensed phase.     

Homogenization procedure for a metamaterial and local violation of the second principle of thermodynamics

Classical theory of crystals states that a medium to be considered homogeneous must satisfy the following requirements (a) the dimension of the elementary cell must be much smaller than the incident wavelength; (b) the sample must contain a large number of elementary cells, i.e. it must be macroscopic with respect to wavelength. Under these conditions, macroscopic quantities can be introduced in order to describe the optical response of the medium. We analytically demonstrate that for a symmetric elementary cell those requirements can be relaxed, and it is possible to assign a permittivity and a permeability to a composite structure, even if the metamaterial cannot be considered homogeneous under the requirements stated above. However, the effective permittivity and permeability in some cases may give rise to unphysical, effective behaviors inside the medium, notwithstanding the fact that they satisfy requirements like being Kramers-Kronig pairs, for example, and are consistent with all the linear properties outside the structure (i.e. reflection, transmission, and absorption at all frequencies). In some situations the medium is assigned a magnetic response even though the medium is not magnetically active. In particular, we demonstrate that the homogenization procedure can lead to a medium that locally violates the second principle of thermodynamics. We also show that, in the non-homogeneous regime, it is not possible to describe the nonlinear behavior of the structure using an effective parameters approach, despite the possibility to assign an effective linear refractive index.     

The External Field Dependence of the BCS Critical Temperature

We consider the Bardeen–Cooper–Schrieffer free energy functional for particles interacting via a two-body potential on a microscopic scale and in the presence of weak external fields varying on a macroscopic scale. We study the influence of the external fields on the critical temperature. We show that in the limit where the ratio between the microscopic and macroscopic scale tends to zero, the next to leading order of the critical temperature is determined by the lowest eigenvalue of the linearization of the Ginzburg–Landau equation.     

Collisional granular flow as a micropolar fluid

We show that a micropolar fluid model successfully describes collisional granular flows on a slope. A micropolar fluid is the fluid with internal structures in which coupling between the spin of each particle and the macroscopic velocity field is taken into account. It is a hydrodynamical framework suitable for granular systems which consists of particles with macroscopic size. We demonstrate that the model equations can quantitatively reproduce the velocity and the angular velocity profiles obtained from the numerical simulation of the collisional granular flow on a slope using a simple estimate for the parameters in the theory.