Modular values and weak values of quantum observables

The concept of a modular value of an observable of a pre- and postselected quantum system is introduced. It is similar in form and in some cases has a close connection to the weak value of an observable, but instead of describing an effective interaction when the coupling is weak, it describes a coupling of any strength but only to qubit meters. The generalization of the concept for a coupling of a composite system to a multiqubit meter provides an explanation of some current experiments.     

An additional moving domain induced by a high absorption domain under the action of collimated light beams

The possibility of formation of a basic (stationary) and an additional (moving) high-absorption domain in an optically bistable system, based on high absorption, is demonstrated. A semiconductor with the absorption coefficient dependent on the concentration of free charge carriers in the conduction band is considered as a nonlinear medium. Under certain conditions, an optical beam passing through the stationary high-absorption domain acquires an annular profile and, after traveling a certain distance, transforms into a Gaussian beam with an intensity on the axis sufficient to switch the medium-beam system to the upper state. This moving domain periodically disappears and reappears due to diffusion processes.     

Reference-wave solutions for the high-frequency fields in inhomogeneous-background random media

Ray theory plays an important role in determining the propagation properties of high-frequency fields and their statistical measures in complicated random environments. For computations of the statistical measures it is therefore desirable to have a solution for the high-frequency field propagating along an isolated ray trajectory. A new reference wave is applied to obtain an analytic solution of the parabolic wave equation that describes propagation along the ray trajectory of the deterministic-background medium. The methodology is based on defining a paired-field measure as a product of an unknown field propagating in a disturbed medium and the complex-conjugate component propagating in a medium without random fluctuations. When a solution of the equation for the paired-field measure is obtained, the solution of the deterministic component can be extracted from the paired solution to determine the solution of the unknown field in an explicit form.     

A mathematical characterization of the physical structure of observers

It is proposed that the physical structure of an observer in quantum mechanics is constituted by a pattern of elementary localized switching events. A key preliminary step in giving mathematical expression to this proposal is the introduction of an equivalence relation on sequences of spacetime sets which relates a sequence to any other sequence to which it can be deformed without change of causal arrangement. This allows an individual observer to be associated with a finite structure. The identification of suitable switching events in the human brain is discussed. A definition is given for the sets of sequences of quantum states which such an observer could occupy. Finally, by providing an a priori probability for such sets, the definitions are incorporated into a complete mathematical framework for a many-worlds interpretation. At a less ambitious level, the paper can be read as an exploration of some of the technical and conceptual difficulties involved in constructing such a framework.     

In vitro investigation of the behaviour of magnetic particles by a circulating artery model

Magnetic drug targeting is the use of coated magnetic nanoparticles as carriers for cytostatic drugs. After intraarterial application of these carriers, they are attracted with an external magnetic field to, for example, an experimental VX2 tumour. The biological compatibility of this system depends on several physiological and physical parameters. We established an in vitro model to simulate in vivo conditions in a circulating system consisting of a circuit with an intact bovine femoral artery close to an external magnetic field. Nanoparticle suspensions were applied by a side inlet. After the magnetisation procedure particle size, concentration and distribution was examined.     

Symbols of a cosmic order

The world runs on networks over which signals communicate sequences of symbols, e.g. numerals. Examining both engineered and natural communications networks reveals an unsuspected order that depends on contact with an unpredictable entity. This order has three roots. The first is a proof within quantum theory that no evidence can ever determine its explanation, so that an agent choosing an explanation must do so unpredictably. The second root is the showing that clocks that step computers do not “tell time” but serve as self-adjusting symbol-handling agents that regulate “logically synchronized” motion in response to unpredictable disturbances. Such a clock-agent has a certain independence as well as the capacity to communicate via unpredictable symbols with other clock-agents and to adjust its own tick rate in response to that communication. The third root is the noticing of unpredictable symbol exchange in natural systems, including the transmission of symbols found in molecular biology. We introduce a symbol-handling agent as a role played in some cases by a person, for example a physicist who chooses an explanation of given experimental outcomes, and in other cases by some other biological entity, and in still other cases by an inanimate device, such as a computer-based detector used in physical measurements. While we forbear to try to explain the propensity of agents at all levels from cells to civilizations to form and operate networks of logically synchronized symbol-handling agents, we point to this propensity as an overlooked cosmic order, an order structured by the unpredictability ensuing from the proof. Appreciating the cosmic order leads to a conception of agency that replaces volition by unpredictability and reconceives the notion of objectivity in a way that makes a place for agency in the world as described by physics. Some specific implications for physics are outlined.     

Magneto-optical effects in crystals at the normal incidence

We consider the interaction of a polarized electromagnetic wave in a magnetically ordered crystal plate surrounded by an isotropic ambient at the normal incidence. The crystalline medium of the plate is specified by the general non-symmetric permittivity tensor. The results are expressed in terms of the transmission and reflection matrices which relate the electric fields of the incident wave to those of transmitted and reflected waves. Their applications are illustrated by examples of an isotropic plate magnetized normal to the interface, a cubic crystal magnetized parallel to the interface and an orthorhombic crystal magnetized along the axis normal to the interface. The effect of the reflection from the interfaces and the interference effect are included. The paper treats the reflection at an interface between an isotropic ambient and an absorbing magnetic crystal at small non-zero angles of incidence. The general reflection matrix is applied to the determination of the magneto-optical effects quadratic in magnetization.     

Using Helmholtz resonator arrays to improve dipole transmission efficiency in waveguide

It is well known that the radiation efficiency of an acoustic dipole is very low, increasing the radiation efficiency of an acoustic dipole is a difficult task, especially in an ordinary waveguide.In addition, current acoustic superlenses all utilize in-phase sources to do the super-resolution imaging, it is almost impossible to realize super-resolution imaging of an acoustic dipole.In this paper, after using the Helmholtz resonator arrays(HRAs) which are placed at the upper and lower surfaces of the waveguide, we observe a large dipole radiation efficiency at the certain frequency, which gives a method to observe an acoustic dipole in the far field and offers a novel model which is promising to realize the superlens with a source of an acoustic dipole.We discuss how the arrangement of HRAs affects the transmission of the acoustic dipole.     

Probability of inconsistencies in theory revision

We present a model for studying communities of epistemically interacting agents who update their belief states by averaging (in a specified way) the belief states of other agents in the community. The agents in our model have a rich belief state, involving multiple independent issues which are interrelated in such a way that they form a theory of the world. Our main goal is to calculate the probability for an agent to end up in an inconsistent belief state due to updating (in the given way). To that end, an analytical expression is given and evaluated numerically, both exactly and using statistical sampling. It is shown that, under the assumptions of our model, an agent always has a probability of less than 2% of ending up in an inconsistent belief state. Moreover, this probability can be made arbitrarily small by increasing the number of independent issues the agents have to judge or by increasing the group size. A real-world situation to which this model applies is a group of experts participating in a Delphi-study.     

Diffraction of a sound wave by the open end of a flanged waveguide with impedance walls

Diffraction of a plane sound wave by the open end of an impedance-wall waveguide connected to an opening in an impedance screen is considered. The plane wave is incident on the waveguide from a free half-space. Two versions of the problem are considered: for a semi-infinite waveguide and for a finite-length waveguide with a specified bottom impedance; the impedances of the walls, screen, and waveguide bottom can be different. The finite-length waveguide can be treated as an open cavity in the impedance screen. For the cavity of zero length, the problem is reduced to the diffraction by an impedance insert in the impedance screen. The solution in the external region determines the scattered field; the solution in the internal region allows one to determine the directional pattern of an array of receivers located in the cavity. The problem is solved using the integral Helmholtz equation with a specially selected Green’s function that provides the fulfillment of the boundary conditions. Formally, the problem is reduced to an infinite system of algebraic equations. The computational results obtained for bistatic and monostatic scattering patterns are presented.     

未知EPR态及其正交态的概率复制

纠缠态在量子计算和量子信息中起着十分重要的作用。利用部分纠缠态作为资源提出了一种方案,根据该方案,能够以某些概率成功地复制出未知的EPR(Einstein Podolsky Rosen)态和它的正交态,使得通信双方都能够获得要传送的EPR态。方案的第一步是采用部分纠缠态作为量子信道去实现EPR态的隐形传态。根据量子不可克隆定理,输入态在发送方受到破坏。方案的第二步通过引入一个辅助量子位,发送者Alice在态的配制者Victor的帮助下,将以联合概率成功地获得未知EPR态和它的正交态。从而实现了量子态的重建。     

Electron transport and permittivity in a plasma with an arbitrary ionic charge

Based on the solution of a linearized kinetic equation for electrons with a Landau collision integral, we develop a theory of electron transport for small perturbations in a completely ionized plasma with an arbitrary ionic charge that is free from any constraints on the characteristic perturbation time and length scales. We calculate the potential and vortex electron fluxes for an arbitrary electron collision frequency that allow the spatial and temporal nonlocal transport to be described. We also derive expressions for the longitudinal and transverse electron permittivities of a collisional plasma with an arbitrary ionic charge that are suitable for describing the plasma response to small perturbations with an arbitrary frequency and wave vector. Using the transverse permittivity, which allows the absorption of an electromagnetic wave to be described in the entire range of plasma parameters (from the strongly collisional to the collisionless one), as an example, we provide a detailed comparison with previously known models.     

Strong signal suppression in single-pump optical parametric amplifiers

We show that the combined action of parametric gain and Raman scattering can lead to the complete suppression of an input optical signal in a single-pump parametric amplifier. This suppression is due to an interference between the two parametric gain modes. The interference occurs only at a set of discrete combinations of pump power, phase mismatch, and frequency detuning. Experimentally we are able to demonstrate over 95% (13 dB) suppression of an input signal in an amplifier with a peak parametric gain of only 6 dB.     

利用共焦扫描显微术和变迹术相结合实现光学超分辨

运用适当形式匠光瞳滤波器民成像系统点振响应的分布，歙 具心于冲击函数的形式，这样就有可能实现光学超分辨，但变迹术的运用往往会因其强烈的旁瓣效应而导致成像系统对比度的急剧下降。本文提出的共焦型超分辨方案则能有效地抑制上述旁瓣。此外，本文学进一瞠提出了实现三维光学超分辨手理论框轲。     

Observation of subcellular nanostructure of single neurons with an illumination mode photon scanning tunneling microscope

We report about the observation of microtubules lying underneath the cell membrane of neural process in neurons with a resolution as high as that of an electron microscope by an illumination mode photon scanning tunneling microscope. Nanoapertures used in our observations were fabricated by means of selective chemical etching and metal coating of an optical fiber. The narrowest observed tube has got an average diameter of 26 nm. Comparing this with its nominal value of 25 nm, the difference which is considered as a measure of resolution (δ) is 1 nm implying a resolution comparable to that of an electron microscope in imaging dielectric specimens. This was possible due to the presence of a boundary between the glass and the metal coating and also due to the use of an aperture of almost the same size as that of the microtubule that enhances the detection.     

Role of population transfer under strong probe conditions in electromagnetically induced transparency

We analyze theoretically the phenomenon of electromagnetically induced transparency (EIT) under conditions where the probe laser is not in the usual weak limit. We consider the effects in both three-level and four-level systems, which are either closed or open (due to losses to an external metastable level). We find that the EIT dip almost disappears in a closed three-level system but survives in an open system. In four-level systems, there is a narrow enhanced-absorption peak (EITA) at line center, which has applications as an optical clock. The peak converts to an EIT dip in a closed system, but again survives in an open system.     

Quantum mechanics in theK-field formalism: Kepler's problem for spin particles

Using the well-known Kepler's problem, an attempt is made to demonstrate a procedure for constructing a nonrelativistic approximation of a quantum-mechanical model for steady states of hydrogen atoms in the K-field formalism. In this model, an electron is assumed to possess an intrinsic moment (spin) which, according to Frenkel, is comparable to the magnetic moment. It is shown that Lyapunov-stable trajectories of the K-particle (a test point particle representing the classical model of an electron in an atom) correspond to the conventional steady states of hydrogen atoms, with the trajectories being similar to those in the spin-zero particle model. The proposed model of the electronic structure in a hydrogen atom provides an insight into the physical cause of the atomic superfine structure and the physical meaning of the constant α=c/mc. Tomsk Polytechnical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 50–54, October, 1999.     

Factorization method for inverse obstacle scattering problem in three-dimensional planar acoustic waveguides

In this paper, we consider the inverse scattering problem of reconstructing a bounded obstacle in a three-dimensional planar waveguide from the scattered near-field data measured on a finite cylindrical surface containing the obstacle and corresponding to infinitely many incident point sources also placed on the measurement surface. The obstacle is allowed to be an impenetrable scatterer or a penetrable scatterer. We establish the validity of the factorization method with the nearfield data to characterize the obstacle in the planar waveguide by constructing an outgoing-to-incoming operator which is an integral operator defined on the measurement surface with the kernel given in terms of an infinite series.