Influence of the lattice topography on a three-dimensional, controllable Brownian motor

We study the influence of the lattice topography and the coupling between motion in different directions, for a three-dimensional Brownian motor based on cold atoms in a double optical lattice. Due to controllable relative spatial phases between the lattices, our Brownian motor can induce drifts in arbitrary directions. Since the lattices couple the different directions, the relation between the phase shifts and the directionality of the induced drift is non trivial. Here is therefore this relation investigated experimentally by systematically varying the relative spatial phase in two dimensions, while monitoring the vertically induced drift and the temperature. A relative spatial phase range of 2pi x 2pi is covered. We show that a drift, controllable both in speed and direction, can be achieved, by varying the phase both parallel and perpendicular to the direction of the measured induced drift. The experimental results are qualitatively reproduced by numerical simulations of a simplified, classical model of the system

A nonadiabatic semi-classical method for dynamics of atoms in optical lattices

We develop a semi-classical method to simulate the motion of atoms in a dissipative optical lattice. Our method treats the internal states of the atom quantum mechanically, including all nonadiabatic couplings, while position and momentum are treated as classical variables. We test our method in the one-dimensional case. Excellent agreement with fully quantum mechanical simulations is found. Our results are much more accurate than those of earlier semi-classical methods based on the adiabatic approximation.Comment: 7 pages, 5 figures, submitted to European Physical Journal

Experimental measurement of efficiency and transport coherence of a cold atom Brownian motor in optical lattices

The rectification of noise into directed movement or useful energy is utilized by many different systems. The peculiar nature of the energy source and conceptual differences between such Brownian motor systems makes a characterization of the performance far from straightforward. In this work, where the Brownian motor consists of atoms interacting with dissipative optical lattices, we adopt existing theory and present experimental measurements for both the efficiency and the transport coherence. We achieve up to 0.3% for the efficiency and 0.01 for the P\'eclet number

CONSUMER PROTECTION—EXPLORING PRIVATE CAUSES OF ACTION FOR VICTIMS OF DATA BREACHES

Data breaches are becoming a norm in modern life. Every year it seems that bigger and bigger attacks are launched, and more and more individuals are harmed. The law has responded by increasing states’ ability to prosecute cybercriminals. A glaring hole exists in this protection though. The state is largely an unharmed party. The real harm is done to individual citizens affected by the breaches. Their data is compromised, their identities are stolen, and their livelihoods are placed at risk. This Article will analyze the issue and propose a solution for increased consumer protection in addition to the current criminal punishments

Consumer Protection—Exploring Private Causes of Action for Victims of Data Breaches

Data breaches are becoming a norm in modern life. Every year it seems that bigger and bigger attacks are launched, and more and more individuals are harmed. The law has responded by increasing states’ ability to prosecute cybercriminals. A glaring hole exists in this protection though. The state is largely an unharmed party. The real harm is done to individual citizens affected by the breaches. Their data is compromised, their identities are stolen, and their livelihoods are placed at risk. This Article will analyze the issue and propose a solution for increased consumer protection in addition to the current criminal punishments

Van der Waals Density Functional for General Geometries

A scheme within density functional theory is proposed that provides a practical way to generalize to unrestricted geometries the method applied with some success to layered geometries [H. Rydberg, et al., Phys. Rev. Lett. 91, 126402 (2003)]. It includes van der Waals forces in a seamless fashion. By expansion to second order in a carefully chosen quantity contained in the long range part of the correlation functional, the nonlocal correlations are expressed in terms of a density-density interaction formula. It contains a relatively simple parametrized kernel, with parameters determined by the local density and its gradient. The proposed functional is applied to rare gas and benzene dimers, where it is shown to give a realistic description.Comment: 4 pages, 4 figure

Laser control for the optimal evolution of pure quantum states

Starting from an initial pure quantum state, we present a strategy for reaching a target state corresponding to the extremum (maximum or minimum) of a given observable. We show that a sequence of pulses of moderate intensity, applied at times when the average of the observable reaches its local or global extremum, constitutes a strategy transferable to different control issues. Among them, post-pulse molecular alignment and orientation are presented as examples. The robustness of such strategies with respect to experimentally relevant parameters is also examined.Comment: 16 pages, 9 figure

Reaching optimally oriented molecular states by laser kicks

We present a strategy for post-pulse orientation aiming both at efficiency and maximal duration within a rotational period. We first identify the optimally oriented states which fulfill both requirements. We show that a sequence of half-cycle pulses of moderate intensity can be devised for reaching these target states.Comment: 4 pages, 3 figure

Identification of genes coding for B cell antigens of Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC) by using phage display

<p>Abstract</p> <p>Background</p> <p>Contagious bovine pleuropneumonia (CBPP) is a mycoplasmal disease caused by <it>Mycoplasma mycoides </it>subsp. <it>mycoides </it>SC (<it>Mmm</it>SC). Since the disease is a serious problem that can affect cattle production in parts of Africa, there is a need for an effective and economical vaccine. Identifying which of the causative agent's proteins trigger potentially protective immune responses is an important step towards developing a subunit vaccine. Accordingly, the purpose of this study was to determine whether phage display combined with bioinformatics could be used to narrow the search for genes that code for potentially immunogenic proteins of <it>Mmm</it>SC. Since the production of IgG2 and IgA are associated with a Th₁cellular immune response which is implicated in protection against CBPP, antigens which elicit these immunoglobulin subclasses may be useful in developing a subunit vaccine.</p> <p>Results</p> <p>A filamentous phage library displaying a repertoire of peptides expressed by fragments of the genome of <it>MmmSC </it>was constructed. It was subjected to selection using antibodies from naturally- and experimentally-infected cattle. Mycoplasmal genes were identified by matching the nucleotide sequences of DNA from immunoselected phage particles with the mycoplasmal genome. This allowed a catalogue of genes coding for the proteins that elicited an immune response to be compiled. Using this method together with computer algorithms designed to score parameters that influence surface accessibility and hence potential antigenicity, five genes (<it>abc, gapN, glpO, lppB </it>and <it>ptsG</it>) were chosen to be expressed in <it>Escherichia coli</it>. After appropriate site-directed mutagenesis, polypeptides representing portions of each of these proteins were tested for immunoreactivity. Of these five, polypeptides representing expression products of <it>abc </it>and <it>lppB </it>were recognised on immunoblots by sera obtained from cattle during a natural outbreak of the disease.</p> <p>Conclusion</p> <p>Since phage display physically couples phenotype with genotype, it was used to compile a list of sequences that code for <it>Mmm</it>SC proteins bearing epitopes which were recognised by antibodies in the serum of infected animals. Together with the appropriate bioinformatic analyses, this approach provided several potentially useful vaccine or diagnostic leads. The phage display step empirically identified sequences by their interaction with antibodies which accordingly reduced the number of ORFs that had to be expressed for testing. This is a particular advantage when working with <it>Mmm</it>SC since the mycoplasmal codon for tryptophan needs to be mutated to prevent it from being translated as a stop in <it>E. coli</it>.</p

Electrically switchable entanglement channel in van der Waals magnets

Two-dimensional layered van der Waals (vdW) magnets demonstrate their potential to allow the study of both fundamental and applied physics due to their remarkable electronic properties. However, the connection of vdW magnets to spintronics and quantum information science is not clear. In particular, it remains elusive whether there are interesting magnetic phenomena belonging only to vdW magnets but absent in widely studied crystalline magnets. Here, we consider the quantum correlations of magnons in a layered vdW magnet and identify an entanglement channel of magnons across the magnetic layers, which can be effectively tuned and even deterministically switched on and off by both magnetic and electric means. This is a unique feature of vdW magnets, in which the underlying physics is well understood in terms of the competing roles of exchange and anisotropy fields that contribute to magnon excitation. Furthermore, we show that such a tunable entanglement channel can mediate the electrically controllable entanglement of two distant qubits, which also provides a protocol to indirectly measure the entanglement of magnons. Our findings provide an avenue to electrically manipulate qubits and further open up opportunities to utilize vdW magnets for quantum information scienc