WorldWideScience

Sample records for butanediacetal-protected chiral non-racemic

  1. Highly Stereoselective Methylene Transfers onto Butanediacetal-Protected Chiral Non-Racemic Sulfinyl Imines Using S-Ylide Technology

    Science.gov (United States)

    Bettigeri, Sampada V.; Pischek, Susanna C.

    2009-01-01

    Reaction of sulfur ylide with chiral non-racemic imine afforded the desired aziridine in excellent yield. Diastereomeric ratios of >95:5 were obtained. Both enantiomeric lines of the butanediacetal-protected chiral non-racemic sulfinyl imines were examined. The sulfur ylides were generated in situ upon thermal decarboxylation of carboxylmethyl betaine functionality. The enantiomeric pairs of D-mannitol with (S)-(-)-2-methyl-2-propane sulfinamide and ascorbic acid with (R)-(-)-2-methyl-2-propane sulfinamide resulted in the highest levels of diastereocontrol when performing aziridination reactions. PMID:19319433

  2. Enantioselective sorption of the chiral fungicide metalaxyl on soil from non-racemic aqueous solutions: Environmental implications.

    Science.gov (United States)

    Celis, Rafael; Gámiz, Beatriz; Facenda, Gracia; Hermosín, María C

    2015-12-30

    Mechanisms governing the enantioselectivity of the processes that determine the behavior of chiral pollutants in the environment need to be better understood. Understanding these mechanisms should help improve predictions of the hazards and risks chiral compounds can pose to people and the environment. We report the results of batch sorption experiments indicating that the sorption of the chiral fungicide metalaxyl on soil from non-racemic initial solutions was enantioselective. While from a racemic initial solution the two enantiomers of metalaxyl were sorbed on the soil to the same extent, increasing the fraction of R-enantiomer in the initial solution led to enhanced sorption of this enantiomer and to reduced sorption of the S-enantiomer. Considering the shape of the sorption isotherms (S-type) and the sorption behavior of model sorbents, we attributed this effect to molecular interactions between metalaxyl enantiomer species at the sorbed state, where R-R metalaxyl interactions appeared to be more favorable than R-S metalaxyl interactions. We discuss important environmental implications of the proposed mechanism, such as those related to the fact that the biological degradation of metalaxyl is known to be an enantioselective process that can yield non-racemic residues in soils shortly after application of the fungicide as a racemic mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Non-racemic mixture model: a computational approach.

    Science.gov (United States)

    Polanco, Carlos; Buhse, Thomas

    2017-01-01

    The behavior of a slight chiral bias in favor of l-amino acids over d-amino acids was studied in an evolutionary mathematical model generating mixed chiral peptide hexamers. The simulations aimed to reproduce a very generalized prebiotic scenario involving a specified couple of amino acid enantiomers and a possible asymmetric amplification through autocatalytic peptide self-replication while forming small multimers of a defined length. Our simplified model allowed the observation of a small ascending but not conclusive tendency in the l-amino acid over the d-amino acid profile for the resulting mixed chiral hexamers in computer simulations of 100 peptide generations. This simulation was carried out by changing the chiral bias from 1% to 3%, in three stages of 15, 50 and 100 generations to observe any alteration that could mean a drastic change in behavior. So far, our simulations lead to the assumption that under the exposure of very slight non-racemic conditions, a significant bias between l- and d-amino acids, as present in our biosphere, was unlikely generated under prebiotic conditions if autocatalytic peptide self-replication was the main or the only driving force of chiral auto-amplification.

  4. Non-racemic amino acids in the Murray and Murchison meteorites.

    Science.gov (United States)

    Pizzarello, S; Cronin, J R

    2000-01-01

    Small (1.0-9.2%) L-enantiomer excesses were found in six alpha-methyl-alpha-amino alkanoic acids from the Murchison (2.8-9.2%) and Murray (1.0-6.0%) carbonaceous chondrites by gas chromatography-mass spectroscopy of their N-trifluoroacetyl or N-pentafluoropropyl isopropyl esters. These amino acids [2-amino-2,3-dimethylpentanoic acid (both diastereomers), isovaline, alpha-methyl norvaline, alpha-methyl valine, and alpha-methyl norleucine] are either unknown or rare in the terrestrial biosphere. Enantiomeric excesses were either not observed in the four alpha-H-alpha-amino alkanoic acids analyzed (alpha-amino-n-butyric acid, norvaline, alanine, and valine) or were attributed to terrestrial contamination. The substantial excess of L-alanine reported by others was not found in the alanine in fractionated extracts of either meteorite. The enantiomeric excesses reported for the alpha-methyl amino acids may be the result of partial photoresolution of racemic mixtures caused by ultraviolet circularly polarized light in the presolar cloud. The alpha-methyl-alpha-amino alkanoic acids could have been significant in the origin of terrestrial homochirality given their resistance to racemization and the possibility for amplification of their enantiomeric excesses suggested by the strong tendency of their polymers to form chiral secondary structure.

  5. Non-racemic Amino Acid Production by Ultraviolet Irradiation of Achiral Interstellar Ice Analogs with Circularly Polarized Light

    Science.gov (United States)

    de Marcellus, Pierre; Meinert, Cornelia; Nuevo, Michel; Filippi, Jean-Jacques; Danger, Grégoire; Deboffle, Dominique; Nahon, Laurent; Le Sergeant d'Hendecourt, Louis; Meierhenrich, Uwe J.

    2011-02-01

    The delivery of organic matter to the primitive Earth via comets and meteorites has long been hypothesized to be an important source for prebiotic compounds such as amino acids or their chemical precursors that contributed to the development of prebiotic chemistry leading, on Earth, to the emergence of life. Photochemistry of inter/circumstellar ices around protostellar objects is a potential process leading to complex organic species, although difficult to establish from limited infrared observations only. Here we report the first abiotic cosmic ice simulation experiments that produce species with enantiomeric excesses (e.e.'s). Circularly polarized ultraviolet light (UV-CPL) from a synchrotron source induces asymmetric photochemistry on initially achiral inter/circumstellar ice analogs. Enantioselective multidimensional gas chromatography measurements show significant e.e.'s of up to 1.34% for (13C)-alanine, for which the signs and absolute values are related to the helicity and number of CPL photons per deposited molecule. This result, directly comparable with some L excesses measured in meteorites, supports a scenario in which exogenous delivery of organics displaying a slight L excess, produced in an extraterrestrial environment by an asymmetric astrophysical process, is at the origin of biomolecular asymmetry on Earth. As a consequence, a fraction of the meteoritic organic material consisting of non-racemic compounds may well have been formed outside the solar system. Finally, following this hypothesis, we support the idea that the protosolar nebula has indeed been formed in a region of massive star formation, regions where UV-CPL of the same helicity is actually observed over large spatial areas.

  6. From helical to planar chirality by on-surface chemistry.

    Science.gov (United States)

    Stetsovych, Oleksandr; Švec, Martin; Vacek, Jaroslav; Chocholoušová, Jana Vacek; Jančařík, Andrej; Rybáček, Jiří; Kosmider, Krzysztof; Stará, Irena G; Jelínek, Pavel; Starý, Ivo

    2017-03-01

    The chirality of molecular structures is paramount in many phenomena, including enantioselective reactions, molecular self-assembly, biological processes and light or electron-spin polarization. Flat prochiral molecules, which are achiral in the gas phase or solution, can exhibit adsorption-induced chirality when deposited on surfaces. The whole array of such molecular adsorbates is naturally racemic as spontaneous global mirror-symmetry breaking is disfavoured. Here we demonstrate a chemical method of obtaining flat prochiral molecules adsorbed on the solid achiral surface in such a way that a specific adsorbate handedness globally dominates. An optically pure helical precursor is flattened in a cascade of on-surface reactions, which enables chirality transfer. The individual reaction products are identified by high-resolution scanning-probe microscopy. The ultimate formation of globally non-racemic assemblies of flat molecules through stereocontrolled on-surface synthesis allows for chirality to be expressed in as yet unexplored types of organic-inorganic chiral interfaces.

  7. From helical to planar chirality by on-surface chemistry

    Science.gov (United States)

    Stetsovych, Oleksandr; Švec, Martin; Vacek, Jaroslav; Chocholoušová, Jana Vacek; Jančařík, Andrej; Rybáček, Jiří; Kosmider, Krzysztof; Stará, Irena G.; Jelínek, Pavel; Starý, Ivo

    2016-11-01

    The chirality of molecular structures is paramount in many phenomena, including enantioselective reactions, molecular self-assembly, biological processes and light or electron-spin polarization. Flat prochiral molecules, which are achiral in the gas phase or solution, can exhibit adsorption-induced chirality when deposited on surfaces. The whole array of such molecular adsorbates is naturally racemic as spontaneous global mirror-symmetry breaking is disfavoured. Here we demonstrate a chemical method of obtaining flat prochiral molecules adsorbed on the solid achiral surface in such a way that a specific adsorbate handedness globally dominates. An optically pure helical precursor is flattened in a cascade of on-surface reactions, which enables chirality transfer. The individual reaction products are identified by high-resolution scanning-probe microscopy. The ultimate formation of globally non-racemic assemblies of flat molecules through stereocontrolled on-surface synthesis allows for chirality to be expressed in as yet unexplored types of organic-inorganic chiral interfaces.

  8. Evidence for the effect of sorption enantioselectivity on the availability of chiral pesticide enantiomers in soil.

    Science.gov (United States)

    Gámiz, Beatriz; Facenda, Gracia; Celis, Rafael

    2016-06-01

    Although enantioselective sorption to soil particles has been proposed as a mechanism that can potentially influence the availability of individual chiral pesticide enantiomers in the environment, environmental fate studies generally overlook this possibility and assume that only biotic processes can be enantioselective, whereas abiotic processes, such as sorption, are non-enantioselective. In this work, we present direct evidence for the effect of the enantioselective sorption of a chiral pesticide in a natural soil on the availability of the single pesticide enantiomers for transport. Batch sorption experiments, with direct determination of the sorbed amounts, combined with column leaching tests confirmed previous observations that from non-racemic aqueous solutions the sorption of the chiral fungicide metalaxyl on the soil appeared to be enantioselective, and further demonstrated that the enantiomer that was sorbed to a greater extent (R-metalaxyl, Kd = 1.73 L/kg) exhibited retarded leaching compared to its optical isomer (S-metalaxyl, Kd = 1.15 L/kg). Interconversion and degradation of the pesticide enantiomers, which are potential experimental artifacts that can lead to erroneous estimates of sorption and its enantioselectivity, were discarded as possible causes of the observed enantioselective behavior. The results presented here may have very important implications for a correct assessment of the environmental fate of chiral pesticides that are incorporated into the environment as non-racemic mixtures, and also of aged chiral pesticide residues that have been transformed from racemic to non-racemic by biologically-mediated processes.

  9. Discovery of the First Interstellar Chiral Molecule: Propylene Oxide

    Science.gov (United States)

    Carroll, Brandon; McGuire, Brett A.; Loomis, Ryan; Finneran, Ian A.; Jewell, Philip; Remijan, Anthony; Blake, Geoffrey

    2016-06-01

    Life on Earth relies on chiral molecules, that is, species not superimposable on their mirror images. This manifests itself as a reliance on a single molecular handedness, or homochirality that is characteristic of life and perhaps most readily apparent in the large enhancement in biological activity of particular amino acid and sugar enantiomers. Yet, the ancestral origin of biological homochirality remains a mystery. The non-racemic ratios in some organics isolated from primitive meteorites hint at a primordial chiral seed but even these samples have experienced substantial processing during planetary assembly, obscuring their complete histories. To determine the underlying origin of any enantiomeric excess, it is critical to understand the molecular gas from which these molecules originated. Here, we present the first extra-solar, astronomical detection of a chiral molecule, propylene oxide (CH_3CHCH_2O), in absorption toward the Galactic Center. With the detection of propylene oxide, we at last have a target for broad-ranging searches for the possible cosmic origin of the homochirality of life.

  10. Chiral photochemistry

    CERN Document Server

    Inoue, Yoshihisa

    2004-01-01

    Direct Asymmetric Photochemistry with Circularly Polarized Light, H. RauCoherent Laser Control of the Handedness of Chiral Molecules, P. Brumer and M. ShapiroMagnetochiral Anisotropy in Asymmetric Photochemistry, G.L.J.A.RikkenEnantiodifferentiating Photosensitized Reactions, Y. InoueDiastereodifferentiating Photoreactions, N. Hoffmann and J.-P. PeteChirality in Photochromism, Y. Yokoyama and M. SaitoChiral Photochemistry with Transition Metal Complexes, S. Sakaki and T. HamadaTemplate-Induced Enantioselective Photochemical Reactions in S

  11. Chiral algebras

    CERN Document Server

    Beilinson, Alexander

    2004-01-01

    Chiral algebras form the primary algebraic structure of modern conformal field theory. Each chiral algebra lives on an algebraic curve, and in the special case where this curve is the affine line, chiral algebras invariant under translations are the same as well-known and widely used vertex algebras. The exposition of this book covers the following topics: the "classical" counterpart of the theory, which is an algebraic theory of non-linear differential equations and their symmetries; the local aspects of the theory of chiral algebras, including the study of some basic examples, such as the ch

  12. Enantiomeric excesses of chiral amines in ammonia-rich carbonaceous meteorites

    Science.gov (United States)

    Pizzarello, Sandra; Yarnes, Christopher T.

    2016-06-01

    Chiral homogeneity is essential to the structure and function of terrestrial biopolymers but the origin of this "homochirality" is poorly understood and remains one of the many unknowns surrounding the origins of life. Several amino acids extracted from Carbonaceous Chondrite meteorites display L-enantiomeric excesses (ee) and their findings have encouraged suggestions that an input of non-racemic meteoritic compounds to early Earth might have led to terrestrial homochirality. Motivated by occasional indications of possible ee in other classes of soluble meteoritic compounds, we have undertaken a systematic study of the chiral distribution of amines in Renazzo-type (CR) meteorites, where they are the second most abundant organic molecular species and ammonia is by far the most abundant single molecule. We report here the first time finding of L-ee for two chiral amines in several pristine CR meteorites from Antarctica and outline a proposal by which the compounds possibly formed from the same ketone precursors as some of the chiral amino acids. This would occur during a warm hydrous stage of the asteroidal parent body, via a reductive amination process in the presence of a large abundance of ammonia, where the precursors' adsorption upon mineral phases possessing asymmetry offered the opportunity for chiral induction. Because the precursor ketones are achiral, the proposal underscores the likelihood of diverse asymmetric influences and processes in cosmochemistry.

  13. Chiral superconductors.

    Science.gov (United States)

    Kallin, Catherine; Berlinsky, John

    2016-05-01

    Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a chiral triplet p-wave superconductor, and UPt3, which has two low-temperature superconducting phases (in zero magnetic field), the lower of which is believed to be chiral triplet f-wave. Other systems that may exhibit chiral superconductivity are also discussed. Key signatures of chiral superconductivity are surface currents and chiral Majorana modes, Majorana states in vortex cores, and the possibility of half-flux quantum vortices in the case of triplet pairing. Experimental evidence for chiral superconductivity from μSR, NMR, strain, polar Kerr effect and Josephson tunneling experiments are discussed.

  14. Isotopic chirality

    Energy Technology Data Exchange (ETDEWEB)

    Floss, H.G. [Univ. of Washington, Seattle, WA (United States)

    1994-12-01

    This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

  15. Life's First Handshake - Discovery of the Interstellar Chiral Molecule Propylene Oxide

    Science.gov (United States)

    McGuire, Brett A.; Carroll, P. Brandon; Loomis, Ryan A.; Finneran, Ian A.; Jewell, Philip R.; Remijan, Anthony J.; Blake, Geoffrey A.

    2016-06-01

    Life on Earth relies on chiral molecules, that is, species not superimposable on their mirror images. This manifests itself in the selection of a single molecular handedness, or homochirality, across the biosphere, and is perhaps most readily apparent in the large enhancement in biological activity of particular amino acid and sugar enantiomers. Yet, the ancestral origin of biological homochirality remains a mystery. The non-racemic ratios in some organics isolated from primitive meteorites hint at a primordial chiral seed, but even these samples have experienced substantial processing during planetary assembly, obscuring their complete histories. To determine the underlying origin of any enantiomeric excess, it is critical to understand the molecular gas from which these molecules originated. Here, we present the first extra-solar, astronomical detection of a chiral molecule, propylene oxide (CH3CHCH2O), in absorption toward the Galactic Center. We discuss the implications of the detection on observational searches to determine a primordial chiral excess, as well as the state of laboratory efforts in these areas.

  16. Chirality emergence in thin solid films of amino acids by polarized light from synchrotron radiation and free electron laser.

    Science.gov (United States)

    Takahashi, Jun-ichi; Shinojima, Hiroyuki; Seyama, Michiko; Ueno, Yuko; Kaneko, Takeo; Kobayashi, Kensei; Mita, Hajime; Adachi, Mashahiro; Hosaka, Masahito; Katoh, Masahiro

    2009-07-07

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of "chiral impulse" as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario). To experimentally introduce chiral structure into racemic films of amino acids (alanine, phenylalanine, isovaline, etc.), we irradiated them with linearly polarized light (LPL) from synchrotron radiation and circularly polarized light (CPL) from a free electron laser. After the irradiation, we evaluated optical anisotropy by measuring the circular dichroism (CD) spectra and verified that new Cotton peaks appeared at almost the same peak position as those of the corresponding non-racemic amino acid films. With LPL irradiation, two-dimensional anisotropic structure expressed as linear dichroism and/or linear birefringence was introduced into the racemic films. With CPL irradiation, the signs of the Cotton peaks exhibit symmetrical structure corresponding to the direction of CPL rotation. This indicates that some kinds of chiral structure were introduced into the racemic film. The CD spectra after CPL irradiation suggest the chiral structure should be derived from not only preferential photolysis but also from photolysis-induced molecular structural change. These results suggest that circularly polarized light sources in space could be associated with the origin of terrestrial homochirality; that is, they would be effective asymmetric exciting sources introducing chiral structures into bio-organic molecules or complex organic compounds.

  17. Chirality Emergence in Thin Solid Films of Amino Acids by Polarized Light from Synchrotron Radiation and Free Electron Laser

    Directory of Open Access Journals (Sweden)

    Mashahiro Adachi

    2009-07-01

    Full Text Available One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of “chiral impulse” as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario. To experimentally introduce chiral structure into racemic films of amino acids (alanine, phenylalanine, isovaline, etc., we irradiated them with linearly polarized light (LPL from synchrotron radiation and circularly polarized light (CPL from a free electron laser. After the irradiation, we evaluated optical anisotropy by measuring the circular dichroism (CD spectra and verified that new Cotton peaks appeared at almost the same peak position as those of the corresponding non-racemic amino acid films. With LPL irradiation, two-dimensional anisotropic structure expressed as linear dichroism and/or linear birefringence was introduced into the racemic films. With CPL irradiation, the signs of the Cotton peaks exhibit symmetrical structure corresponding to the direction of CPL rotation. This indicates that some kinds of chiral structure were introduced into the racemic film. The CD spectra after CPL irradiation suggest the chiral structure should be derived from not only preferential photolysis but also from photolysis-induced molecular structural change. These results suggest that circularly polarized light sources in space could be associated with the origin of terrestrial homochirality; that is, they would be effective asymmetric exciting sources introducing chiral structures into bio-organic molecules or complex organic compounds.

  18. Chiral liquids

    Directory of Open Access Journals (Sweden)

    Zakharov V.I.

    2015-01-01

    Full Text Available We review briefly properties of chiral liquids, or liquids with massless fermionic constituents. We concentrate on three effects, namely, the low ratio of viscosity η to entropy density s, chiral magnetic and vortical effects. We sketch standard derivations of these effects in the hydrodynamic approximation and then concentrate on possibile unifying approach which is based on consideration of the (anomalously conserved axial current. The point is that the conservation of chirality is specific for the microscopic, field-theoretic description of massless fermions and their interactions. On the macroscopic side, the standard hydrodynamic equations are not consistent, generally speaking, with conservation of a helical macroscopic motion. Imposing extra constraints on the hydrodynamics might resolve this “clash-of-symmetries” paradox.

  19. Chiral Nanoscience and Nanotechnology

    OpenAIRE

    Dibyendu S. Bag; T.C. Shami; K.U. Bhasker Rao

    2008-01-01

    The paper reviews nanoscale science and technology of chiral molecules/macromolecules-under twosubtopics-chiral nanotechnology and nano-chiral technology. Chiral nanotechnology discusses thenanotechnology, where molecular chirality plays a role in the properties of materials, including molecularswitches, molecular motors, and other molecular devices; chiral supramolecules and self-assembled nanotubesand their functions are also highlighted. Nano-chiral technology  describes the nanoscale appr...

  20. On Chiral Space Groups and Chiral Molecules

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This note explains the relationship (as well as the absence of a relationship) between chiral space groups and chiral molecules (which have absolute configurations). For a chiral molecule, which must crystallize in a chiral space group, the outcome of the absolute configuration determination must be linked to some other properties of the chiral crystal such as its optical activity for the observation to the relevant.

  1. On Chiral Space Groups and Chiral Molecules

    Institute of Scientific and Technical Information of China (English)

    NgSeikWng; HUSheng-Zhi

    2003-01-01

    This note explains the relationship (as well as the absence of a relationship) between chiral space groups and chiral molecules (which have absolute configurations).For a chiral molecule,which must crystallize in a chiral space group,the outcome of the absolute configuration determination must be linked to some other properties of the chiral crystal such as its optical activity for the observation to the relevant.

  2. Stegosaurus chirality

    OpenAIRE

    Cameron, R.P.; Cameron, J. A.; Barnett, S. M.

    2016-01-01

    We explain that Stegosaurus exhibited exterior chirality and observe that the largest plate in particular of USNM 4394, USNM 4714, DMNS 2818 and NHMUK R36730 appears to have tilted to the right rather than to the left in each case. Several instances in which Stegosaurus specimens have been confused with their distinct, hypothetical mirror-image forms are highlighted. We believe our findings to be consistent with the hypothesis that Stegosaurus's plates acted primarily as display structures. A...

  3. Chiral Nanoscience and Nanotechnology

    Directory of Open Access Journals (Sweden)

    Dibyendu S. Bag

    2008-09-01

    Full Text Available The paper reviews nanoscale science and technology of chiral molecules/macromolecules-under twosubtopics-chiral nanotechnology and nano-chiral technology. Chiral nanotechnology discusses thenanotechnology, where molecular chirality plays a role in the properties of materials, including molecularswitches, molecular motors, and other molecular devices; chiral supramolecules and self-assembled nanotubesand their functions are also highlighted. Nano-chiral technology  describes the nanoscale approaches to chiraltechnology such as asymmetric synthesis and catalysis, chiral separation and detection, and enantiomericanalysis. Chiral sensors have also been included. The state-of-the-art chiral research at DMSRDE,Kanpur isalso presented.Defence Science Journal, 2008, 58(5, pp.626-635, DOI:http://dx.doi.org/10.14429/dsj.58.1685

  4. Chiral mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Plum, Eric, E-mail: erp@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Zheludev, Nikolay I., E-mail: niz@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637378 (Singapore)

    2015-06-01

    Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media.

  5. Molecular chirality at surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Karl-Heinz [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf (Switzerland); Organic Chemistry Institute, University Zurich, 8057 Zuerich (Switzerland)

    2012-11-15

    With the adsorption of larger molecules being increasingly tackled by surface scientists, the aspect of chirality often plays a role. This paper gives a topical review of molecular chirality at surfaces and gives a phenomenological overview of different aspects of adsorption and self-assembly of chiral and prochiral molecules and the principles of mirror-symmetry breaking at a surface. After a brief introduction into the history of molecular chirality and the important role it played for understanding the spatial structure of molecules, definitions of chirality are presented. Topics treated here are principle ways to create single chiral adsorbates, chiral ensembles, and monolayers by achiral molecules, adsorption of intrinsically chiral molecules at achiral and chiral surfaces, long-range symmetry breaking in two-dimensional (2D) crystals due to additional chiral bias, chiral restructuring of solid surfaces under the influence of chiral molecules, switching the handedness of adsorbates, and chirality at the liquid/air interface. An outlook onto further potential research directions and recommendations for further reading, including nonsurface-related sources of chiral topics completes this paper. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Chiral conducting polymers.

    Science.gov (United States)

    Kane-Maguire, Leon A P; Wallace, Gordon G

    2010-07-01

    This critical review describes the preparation and properties of a relatively new class of chiral macromolecules, namely chiral conducting polymers. It focuses in particular on examples based on polypyrrole, polythiophene and polyaniline. They possess remarkable properties, combining not only chirality with electrical conductivity but also the ability to undergo facile redox and pH switching. These unique properties have opened up a range of exciting new potential applications, including as chiral sensors, as novel stationary phases for chiral separations, and as chiral electrodes for electrochemical asymmetric synthesis (153 references).

  7. Chiral Gravitational Waves from Chiral Fermions

    CERN Document Server

    Anber, Mohamed M

    2016-01-01

    We report on a new mechanism that leads to the generation of primordial chiral gravitational waves, and hence, the violation of the parity symmetry in the Universe. We show that nonperturbative production of fermions with a definite helicity is accompanied by the generation of chiral gravitational waves. This is a generic and model-independent phenomenon that can occur during inflation, reheating and radiation eras, and can leave imprints in the cosmic microwave background polarization and may be observed in future ground- and space-based interferometers. We also discuss a specific model where chiral gravitational waves are generated via the production of light chiral fermions during pseudoscalar inflation.

  8. Chiral gravitational waves from chiral fermions

    Science.gov (United States)

    Anber, Mohamed M.; Sabancilar, Eray

    2017-07-01

    We report on a new mechanism that leads to the generation of primordial chiral gravitational waves, and hence, the violation of the parity symmetry in the Universe. We show that nonperturbative production of fermions with a definite helicity is accompanied by the generation of chiral gravitational waves. This is a generic and model-independent phenomenon that can occur during inflation, reheating and radiation eras, and can leave imprints in the cosmic microwave background polarization and may be observed in future ground- and space-based interferometers. We also discuss a specific model where chiral gravitational waves are generated via the production of light chiral fermions during pseudoscalar inflation.

  9. Baryons and Chiral Symmetry

    CERN Document Server

    Liu, Keh-Fei

    2016-01-01

    The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of $\\pi N \\sigma$ term and strangeness. The third one is the role of chiral $U(1)$ anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.

  10. Chiral Rotational Spectroscopy

    CERN Document Server

    Cameron, Robert P; Barnett, Stephen M

    2015-01-01

    We introduce chiral rotational spectroscopy: a new technique that enables the determination of the individual optical activity polarisability components $G_{XX}'$, $G_{YY}'$, $G_{ZZ}'$, $A_{X,YZ}$, $A_{Y,ZX}$ and $A_{Z,XY}$ of chiral molecules, in a manner that reveals the enantiomeric constitution of a sample whilst yielding an incisive signal even for a racemate. Chiral rotational spectroscopy could find particular use in the analysis of molecules that are chiral by virtue of their isotopic constitution and molecules with multiple chiral centres. The principles that underpin chiral rotational spectroscopy can also be exploited in the search for molecular chirality in space, which, if found, may add weight to hypotheses that biological homochirality and indeed life itself are of cosmic origin.

  11. On chiral and non chiral 1D supermultiplets

    Energy Technology Data Exchange (ETDEWEB)

    Toppan, Francesco, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (TEO/CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Fisica Teorica

    2011-07-01

    In this talk I discuss and clarify some issues concerning chiral and non chiral properties of the one-dimensional supermultiplets of the N-extended supersymmetry. Quaternionic chirality can be defined for N = 4, 5, 6, 7, 8. Octonionic chirality for N = 8 and beyond. Inequivalent chiralities only arise when considering several copies of N = 4 or N = 8 supermultiplets. (author)

  12. Chiral symmetry and chiral-symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, M.E.

    1982-12-01

    These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)

  13. Extrinsic electromagnetic chirality in metamaterials

    OpenAIRE

    Plum, E.; Fedotov, V. A.; Zheludev, N. I.

    2009-01-01

    Three- and two-dimensional chirality arising from the mutual orientation of non-chiral planar metamaterial structures and the incident electromagnetic wave (extrinsic chirality) lead to pronounced optical activity, circular dichroism and asymmetric transmission indistinguishable from those seen in media consisting of three- and two-dimensionally chiral molecules (intrinsic chirality).

  14. Gelation induced supramolecular chirality: chirality transfer, amplification and application.

    Science.gov (United States)

    Duan, Pengfei; Cao, Hai; Zhang, Li; Liu, Minghua

    2014-08-14

    Supramolecular chirality defines chirality at the supramolecular level, and is generated from the spatial arrangement of component molecules assembling through non-covalent interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, hydrophobic interactions and so on. During the formation of low molecular weight gels (LMWGs), one kind of fascinating soft material, one frequently encounters the phenomenon of chirality as well as chiral nanostructures, either from chiral gelators or even achiral gelators. A view of gelation-induced supramolecular chirality will be very helpful to understand the self-assembly process of the gelator molecules as well as the chiral structures, the regulation of the chirality in the gels and the development of the "smart" chiral materials such as chiroptical devices, catalysts and chiral sensors. It necessitates fundamental understanding of chirality transfer and amplification in these supramolecular systems. In this review, recent progress in gelation-induced supramolecular chirality is discussed.

  15. Chiral rotational spectroscopy

    Science.gov (United States)

    Cameron, Robert P.; Götte, Jörg B.; Barnett, Stephen M.

    2016-09-01

    We introduce chiral rotational spectroscopy, a technique that enables the determination of the orientated optical activity pseudotensor components BX X, BY Y, and BZ Z of chiral molecules, in a manner that reveals the enantiomeric constitution of a sample and provides an incisive signal even for a racemate. Chiral rotational spectroscopy could find particular use in the analysis of molecules that are chiral solely by virtue of their isotopic constitution and molecules with multiple chiral centers. A basic design for a chiral rotational spectrometer together with a model of its functionality is given. Our proposed technique offers the more familiar polarizability components αX X, αY Y, and αZ Z as by-products, which could see it find use even for achiral molecules.

  16. Chiral Superfluidity for QCD

    CERN Document Server

    Kalaydzhyan, Tigran

    2014-01-01

    We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields or rotation the motion of the "superfluid" component gives rise to the chiral magnetic, chiral vortical, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model.

  17. Emerging chirality in nanoscience.

    Science.gov (United States)

    Wang, Yong; Xu, Jun; Wang, Yawen; Chen, Hongyu

    2013-04-07

    Chirality in nanoscience may offer new opportunities for applications beyond the traditional fields of chirality, such as the asymmetric catalysts in the molecular world and the chiral propellers in the macroscopic world. In the last two decades, there has been an amazing array of chiral nanostructures reported in the literature. This review aims to explore and categorize the common mechanisms underlying these systems. We start by analyzing the origin of chirality in simple systems such as the helical spring and hair vortex. Then, the chiral nanostructures in the literature were categorized according to their material composition and underlying mechanism. Special attention is paid to highlight systems with original discoveries, exceptional structural characteristics, or unique mechanisms.

  18. Mechanical separation of chiral dipoles by chiral light

    CERN Document Server

    Canaguier-Durand, Antoine; Genet, Cyriaque; Ebbesen, Thomas W

    2013-01-01

    Optical forces take on a specific form when involving chiral light fields interacting with chiral objects. We show that optical chirality density and flow can have mechanical effects through reactive and dissipative components of chiral forces exerted on chiral dipoles. Remarkably, these force components are directly related to standard observables: optical rotation and circular dichroism, respectively. As a consequence, resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This leads to promising strategies for the mechanical separation of chiral objects using chiral light forces.

  19. Chiral atomically thin films

    Science.gov (United States)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  20. Chiral Shock Waves

    CERN Document Server

    Sen, Srimoyee

    2016-01-01

    We study shock waves in relativistic chiral matter. We argue that the conventional Rankine- Hugoinot relations are modified due to the presence of chiral transport phenomena. We show that the entropy discontinuity in a weak shock wave is linearly proportional to the pressure discontinuity when the effect of chiral transport becomes sufficiently large. We also show that rarefaction shock waves, which do not exist in usual nonchiral fluids, can appear in chiral matter. These features are exemplified by shock propagation in dense neutrino matter in the hydrodynamic regime.

  1. Anomalous chiral superfluidity

    Energy Technology Data Exchange (ETDEWEB)

    Lublinsky, Michael, E-mail: lublinsky@phys.uconn.ed [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Physics Department, Ben-Gurion University, Beer Sheva 84105 (Israel); Zahed, Ismail [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

    2010-02-08

    We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavor anomalies as an effective theory for flavored chiral phonons in a chiral superfluid with the gauged Wess-Zumino-Witten term. In the mean-field (leading tadpole) approximation the anomalous Cartan currents and the energy-momentum tensor take the form of constitutive currents in the chiral superfluid state. The pertinence of higher order corrections and the Adler-Bardeen theorem is briefly noted.

  2. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  3. Applications of chiral symmetry

    CERN Document Server

    Pisarski, R D

    1995-01-01

    I discuss several topics in the applications of chiral symmetry at nonzero temperature, including: where the rho goes, disoriented chiral condensates, and the phase diagram for QCD with 2+1 flavors. (Based upon talks presented at the "Workshop on Finite Temperature QCD", Wuhan, P.R.C., April, 1994.)

  4. Geometrical approach to central molecular chirality: a chirality selection rule

    OpenAIRE

    Capozziello, S.; Lattanzi, A

    2004-01-01

    Chirality is of primary importance in many areas of chemistry and has been extensively investigated since its discovery. We introduce here the description of central chirality for tetrahedral molecules using a geometrical approach based on complex numbers. According to this representation, for a molecule having n chiral centres, it is possible to define an index of chirality. Consequently a chirality selection rule has been derived which allows the characterization of a molecule as achiral, e...

  5. Molecular model for chirality phenomena.

    Science.gov (United States)

    Latinwo, Folarin; Stillinger, Frank H; Debenedetti, Pablo G

    2016-10-21

    Chirality is a hallmark feature for molecular recognition in biology and chemical physics. We present a three-dimensional continuum model for studying chirality phenomena in condensed phases using molecular simulations. Our model system is based upon a simple four-site molecule and incorporates non-trivial kinetic behavior, including the ability to switch chirality or racemize, as well as thermodynamics arising from an energetic preference for specific chiral interactions. In particular, we introduce a chiral renormalization parameter that can locally favor either homochiral or heterochiral configurations. Using this model, we explore a range of chirality-specific phenomena, including the kinetics of chiral inversion, the mechanism of spontaneous chiral symmetry breaking in the liquid, chirally driven liquid-liquid phase separation, and chiral crystal structures.

  6. Applications of chiral symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Pisarski, R.D.

    1995-03-01

    The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T{sub {chi}} implies that the {rho} and a{sub 1} vector mesons are degenerate in mass. In a gauged linear sigma model the {rho} mass increases with temperature, m{sub {rho}}(T{sub {chi}}) > m{sub {rho}}(0). The author conjectures that at T{sub {chi}} the thermal {rho} - a{sub 1}, peak is relatively high, at about {approximately}1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The {omega} meson also increases in mass, nearly degenerate with the {rho}, but its width grows dramatically with temperature, increasing to at least {approximately}100 MeV by T{sub {chi}}. The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from {open_quotes}quenched{close_quotes} heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates.

  7. Chiral supergravity and anomalies

    CERN Document Server

    Mielke, E W; Macias, Alfredo; Mielke, Eckehard W.

    1999-01-01

    Similarily as in the Ashtekar approach, the translational Chern-Simons term is, as a generating function, instrumental for a chiral reformulation of simple (N=1) supergravity. After applying the algebraic Cartan relation between spin and torsion, the resulting canonical transformation induces not only decomposition of the gravitational fields into selfdual and antiselfdual modes, but also a splitting of the Rarita-Schwinger fields into their chiral parts in a natural way. In some detail, we also analyze the consequences for axial and chiral anomalies.

  8. Spectral signatures of chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We present a new way of measuring chirality, via the spectral shift of photonic band gaps in one-dimensional structures. We derive an explicit mapping of the problem of oblique incidence of circularly polarized light on a chiral one-dimensional photonic crystal with negligible index contrast...... to the formally equivalent problem of linearly polarized light incident on-axis on a non-chiral structure with index contrast. We derive analytical expressions for the first-order shifts of the band gaps for negligible index contrast. These are modified to give good approximations to the band gap shifts also...

  9. Catalysis of Dynamical Chiral Symmetry Breaking by Chiral Chemical Potential

    CERN Document Server

    Braguta, V V

    2016-01-01

    In this paper we study the properties of media with chiral imbalance parameterized by chiral chemical potential. It is shown that depending on the strength of interaction between constituents in the media the chiral chemical potential either creates or enhances dynamical chiral symmetry breaking. Thus the chiral chemical potential plays a role of the catalyst of dynamical chiral symmetry breaking. Physically this effect results from the appearance of the Fermi surface and additional fermion states on this surface which take part in dynamical chiral symmetry breaking. An interesting conclusion which can be drawn is that at sufficiently small temperature chiral plasma is unstable with respect to condensation of Cooper pairs and dynamical chiral symmetry breaking even for vanishingly small interactions between constituents.

  10. Color chiral solitons

    CERN Document Server

    Novozhilov, V Yu; Novozhilov, Victor; Novozhilov, Yuri

    2002-01-01

    We discuss specific features of color chiral solitons (asymptotics, possibility of confainment, quantization) at example of isolated SU(2) color skyrmions, i.e. skyrmions in a background field which is the vacuum field forming the gluon condensate.

  11. Chiral brownian heat pump.

    Science.gov (United States)

    van den Broek, M; Van den Broeck, C

    2008-04-04

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  12. Chiral Brownian heat pump

    OpenAIRE

    Van Den Broek, Martijn; Van Den Broeck, Christian

    2007-01-01

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  13. Electrodynamics of chiral matter

    Science.gov (United States)

    Qiu, Zebin; Cao, Gaoqing; Huang, Xu-Guang

    2017-02-01

    Many-body systems with chiral fermions can exhibit novel transport phenomena that violate parity and time-reversal symmetries, such as the chiral magnetic effect, the anomalous Hall effect, and the anomalous generation of charge. Based on the Maxwell-Chern-Simons electrodynamics, we examine some electromagnetic and optical properties of such systems including the electrostatics, the magnetostatics, the propagation of electromagnetic waves, the novel optical effects, etc.

  14. Chiral Odd GPDs

    Directory of Open Access Journals (Sweden)

    Goldstein Gary R.

    2015-01-01

    Full Text Available Nucleon spin structure, transversity and the tensor charge are of central importance to understanding the role of QCD in hadronic physics. A new approach to measuring orbital angular momenta of quarks in the proton via twist 3 GPDs is shown. The “flexible parametrization” of chiral even GPDs is reviewed and its transformation into the chiral odd sector is discussed. The resulting parametrization is applied to recent data on π0 and η electroproduction.

  15. Chiral Random Matrix Theory and Chiral Perturbation Theory

    CERN Document Server

    Damgaard, P H

    2011-01-01

    Spontaneous breaking of chiral symmetry in QCD has traditionally been inferred indirectly through low-energy theorems and comparison with experiments. Thanks to the understanding of an unexpected connection between chiral Random Matrix Theory and chiral Perturbation Theory, the spontaneous breaking of chiral symmetry in QCD can now be shown unequivocally from first principles and lattice simulations. In these lectures I give an introduction to the subject, starting with an elementary discussion of spontaneous breaking of global symmetries.

  16. Chiral Random Matrix Theory and Chiral Perturbation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Damgaard, Poul H, E-mail: phdamg@nbi.dk [Niels Bohr International Academy and Discovery Center, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)

    2011-04-01

    Spontaneous breaking of chiral symmetry in QCD has traditionally been inferred indirectly through low-energy theorems and comparison with experiments. Thanks to the understanding of an unexpected connection between chiral Random Matrix Theory and chiral Perturbation Theory, the spontaneous breaking of chiral symmetry in QCD can now be shown unequivocally from first principles and lattice simulations. In these lectures I give an introduction to the subject, starting with an elementary discussion of spontaneous breaking of global symmetries.

  17. Chiral Graphene Quantum Dots.

    Science.gov (United States)

    Suzuki, Nozomu; Wang, Yichun; Elvati, Paolo; Qu, Zhi-Bei; Kim, Kyoungwon; Jiang, Shuang; Baumeister, Elizabeth; Lee, Jaewook; Yeom, Bongjun; Bahng, Joong Hwan; Lee, Jaebeom; Violi, Angela; Kotov, Nicholas A

    2016-02-23

    Chiral nanostructures from metals and semiconductors attract wide interest as components for polarization-enabled optoelectronic devices. Similarly to other fields of nanotechnology, graphene-based materials can greatly enrich physical and chemical phenomena associated with optical and electronic properties of chiral nanostructures and facilitate their applications in biology as well as other areas. Here, we report that covalent attachment of l/d-cysteine moieties to the edges of graphene quantum dots (GQDs) leads to their helical buckling due to chiral interactions at the "crowded" edges. Circular dichroism (CD) spectra of the GQDs revealed bands at ca. 210-220 and 250-265 nm that changed their signs for different chirality of the cysteine edge ligands. The high-energy chiroptical peaks at 210-220 nm correspond to the hybridized molecular orbitals involving the chiral center of amino acids and atoms of graphene edges. Diverse experimental and modeling data, including density functional theory calculations of CD spectra with probabilistic distribution of GQD isomers, indicate that the band at 250-265 nm originates from the three-dimensional twisting of the graphene sheet and can be attributed to the chiral excitonic transitions. The positive and negative low-energy CD bands correspond to the left and right helicity of GQDs, respectively. Exposure of liver HepG2 cells to L/D-GQDs reveals their general biocompatibility and a noticeable difference in the toxicity of the stereoisomers. Molecular dynamics simulations demonstrated that d-GQDs have a stronger tendency to accumulate within the cellular membrane than L-GQDs. Emergence of nanoscale chirality in GQDs decorated with biomolecules is expected to be a general stereochemical phenomenon for flexible sheets of nanomaterials.

  18. Chiral anomalies and differential geometry

    Energy Technology Data Exchange (ETDEWEB)

    Zumino, B.

    1983-10-01

    Some properties of chiral anomalies are described from a geometric point of view. Topics include chiral anomalies and differential forms, transformation properties of the anomalies, identification and use of the anomalies, and normalization of the anomalies. 22 references. (WHK)

  19. Superconductivity in a chiral nanotube

    Science.gov (United States)

    Qin, F.; Shi, W.; Ideue, T.; Yoshida, M.; Zak, A.; Tenne, R.; Kikitsu, T.; Inoue, D.; Hashizume, D.; Iwasa, Y.

    2017-02-01

    Chirality of materials are known to affect optical, magnetic and electric properties, causing a variety of nontrivial phenomena such as circular dichiroism for chiral molecules, magnetic Skyrmions in chiral magnets and nonreciprocal carrier transport in chiral conductors. On the other hand, effect of chirality on superconducting transport has not been known. Here we report the nonreciprocity of superconductivity--unambiguous evidence of superconductivity reflecting chiral structure in which the forward and backward supercurrent flows are not equivalent because of inversion symmetry breaking. Such superconductivity is realized via ionic gating in individual chiral nanotubes of tungsten disulfide. The nonreciprocal signal is significantly enhanced in the superconducting state, being associated with unprecedented quantum Little-Parks oscillations originating from the interference of supercurrent along the circumference of the nanotube. The present results indicate that the nonreciprocity is a viable approach toward the superconductors with chiral or noncentrosymmetric structures.

  20. Quarkyonic Chiral Spirals

    CERN Document Server

    Kojo, Toru; McLerran, Larry; Pisarski, Robert D

    2009-01-01

    We consider the formation of chiral density waves in Quarkyonic matter, which is a phase where cold, dense quarks experience confining forces. We model confinement following Gribov and Zwanziger, taking the gluon propagator, in Coulomb gauge and momentum space, as 1/(p^2)^2. We assume that the number of colors, N, is large, and that the quark chemical potential, mu, is much larger than renormalization mass scale, Lambda_QCD. To leading order in 1/N and Lambda_QCD, a gauge theory with Nf flavors of massless quarks in 3+1 dimensions naturally reduces to a gauge theory in 1+1 dimensions, with an enlarged flavor symmetry of SU(2Nf). Through an anomalous chiral rotation, in two dimensions a Fermi sea of massless quarks maps directly onto the corresponding theory in vacuum. A chiral condensate forms locally, and varies with the spatial position, z, as . Following Schon and Thies, we term this two dimensional pion condensate a (Quarkyonic) chiral spiral. Massive quarks also exhibit chiral spirals, with the magnitude...

  1. Chiral Synthons in Pesticide Syntheses

    NARCIS (Netherlands)

    Feringa, Bernard

    1988-01-01

    The use of chiral synthons in the preparation of enantiomerically pure pesticides is described in this chapter. Several routes to chiral synthons based on asymmetric synthesis or on natural products are illustrated. Important sources of chiral building blocks are reviewed. Furthermore the implicatio

  2. Chiral fermions on the lattice

    CERN Document Server

    Jahn, O; Jahn, Oliver; Pawlowski, Jan M.

    2002-01-01

    We discuss topological obstructions to putting chiral fermions on an even dimensional lattice. The setting includes Ginsparg-Wilson fermions, but is more general. We prove a theorem which relates the total chirality to the difference of generalised winding numbers of chiral projection operators. For an odd number of Weyl fermions this implies that particles and anti-particles live in topologically different spaces.

  3. Chiral Quantum Optics

    CERN Document Server

    Lodahl, Peter; Stobbe, Søren; Schneeweiss, Philipp; Volz, Jürgen; Rauschenbeutel, Arno; Pichler, Hannes; Zoller, Peter

    2016-01-01

    At the most fundamental level, the interaction between light and matter is manifested by the emission and absorption of single photons by single quantum emitters. Controlling light--matter interaction is the basis for diverse applications ranging from light technology to quantum--information processing. Many of these applications are nowadays based on photonic nanostructures strongly benefitting from their scalability and integrability. The confinement of light in such nanostructures imposes an inherent link between the local polarization and propagation direction of light. This leads to {\\em chiral light--matter interaction}, i.e., the emission and absorption of photons depend on the propagation direction and local polarization of light as well as the polarization of the emitter transition. The burgeoning research field of {\\em chiral quantum optics} offers fundamentally new functionalities and applications both for single emitters and ensembles thereof. For instance, a chiral light--matter interface enables...

  4. Doped Chiral Polymer Metamaterials

    Science.gov (United States)

    Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Gordon, Keith L. (Inventor); Sauti, Godfrey (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert G. (Inventor)

    2017-01-01

    Some implementations provide a composite material that includes a first material and a second material. In some implementations, the composite material is a metamaterial. The first material includes a chiral polymer (e.g., crystalline chiral helical polymer, poly-.gamma.-benzyl-L-glutamate (PBLG), poly-L-lactic acid (PLA), polypeptide, and/or polyacetylene). The second material is within the chiral polymer. The first material and the second material are configured to provide an effective index of refraction value for the composite material of 1 or less. In some implementations, the effective index of refraction value for the composite material is negative. In some implementations, the effective index of refraction value for the composite material of 1 or less is at least in a wavelength of one of at least a visible spectrum, an infrared spectrum, a microwave spectrum, and/or an ultraviolet spectrum.

  5. [Chirality and drugs].

    Science.gov (United States)

    Testa, B; Reist, M; Carrupt, P A

    2000-07-01

    The two enantiomers of a chiral drug may have vastly different pharmacodynamic and pharmacokinetic properties. As a result, the research and development of chiral drugs raises specific problems some of which are discussed here. Thus, various pharmacokinetic interactions may involve two enantiomers, as seen for example when one enantiomer inhibits the metabolism of the other and modifies its effects. A different situation occurs when a third compound stereoselectively inhibits the metabolism of one of the two enantiomers. Another problem examined here results from the lack of configurational stability of some chiral drugs, a little known phenomenon whose consequences can be of pharmacological or pharmaceutical significance depending on the rate of the reaction of racemization or epimerisation. In-depth investigations are needed before choosing between a eutomer or a racemate.

  6. Chiral quark model

    Indian Academy of Sciences (India)

    H Weigel

    2003-11-01

    In this talk I review studies of hadron properties in bosonized chiral quark models for the quark flavor dynamics. Mesons are constructed from Bethe–Salpeter equations and baryons emerge as chiral solitons. Such models require regularization and I show that the two-fold Pauli–Villars regularization scheme not only fully regularizes the effective action but also leads the scaling laws for structure functions. For the nucleon structure functions the present approach serves to determine the regularization prescription for structure functions whose leading moments are not given by matrix elements of local operators. Some numerical results are presented for the spin structure functions.

  7. Interweaving Chiral Spirals

    CERN Document Server

    Kojo, Toru; Fukushima, Kenji; McLerran, Larry; Pisarski, Robert D

    2011-01-01

    We elaborate how to construct the interweaving chiral spirals in (2+1) dimensions, that is defined as a superposition of differently oriented chiral spirals. We divide the two-dimensional Fermi sea into distinct wedges characterized by the opening angle 2 Theta and the depth Q \\simeq pF, where pF is the Fermi momentum. Each wedge earns an energy gain by forming a single chiral spiral. The optimal values for Theta and Q are chosen by the balance between this energy gain and the energy costs from the deformed Fermi surface (dominant at large Theta) and patch-patch interactions (dominant at small Theta). We estimate these energy gains and costs by means of the expansions in terms of 1/Nc, Lambda_QCD/Q, and Theta using a non-local four-Fermi interaction model: At small 1/Nc the mass gap (chiral condensate) is large enough and the interaction among quarks and the condensate is local in momentum space thanks to the form factor in our non-local model. The fact that patch-patch interactions lie only near the patch bo...

  8. Simplicial chiral models

    CERN Document Server

    Rossi, P; Rossi, Paolo; Tan, Chung I

    1995-01-01

    Principal chiral models on a d-1 dimensional simplex are introduced and studied analytically in the large N limit. The d = 0 , 2, 4 and \\infty models are explicitly solved. Relationship with standard lattice models and with few-matrix systems in the double scaling limit are discussed.

  9. Chiral magnetic effect without chirality source in asymmetric Weyl semimetals

    CERN Document Server

    Kharzeev, Dmitri; Meyer, Rene

    2016-01-01

    We describe a new type of the Chiral Magnetic Effect (CME) that should occur in Weyl semimetals with an asymmetry in the dispersion relations of the left- and right-handed chiral Weyl fermions. In such materials, time-dependent pumping of electrons from a non-chiral external source generates a non-vanishing chiral chemical potential. This is due to the different capacities of the left- and right-handed (LH and RH) chiral Weyl cones arising from the difference in the density of states in the LH and RH cones. The chiral chemical potential then generates, via the chiral anomaly, a current along the direction of an applied magnetic field even in the absence of an external electric field. The source of chirality imbalance in this new setup is thus due to the band structure of the system and the presence of (non-chiral) electron source, and not due to the parallel electric and magnetic fields. We illustrate the effect by an argument based on the effective field theory, and by the chiral kinetic theory calculation f...

  10. Detecting the chirality for coupled quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Cao Huijuan [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China); Hu Lian [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)], E-mail: huliancaohj@yahoo.com

    2008-04-21

    We propose a scheme to detect the chirality for a system consisting of three coupled quantum dots. The chirality is found to be determined by the frequency of the transition between chiral states under the chiral symmetry broken perturbation. The results are important to construct quantum gates and to demonstrate chiral entangle states in the triangle spin dots.

  11. Soldering Chiralities; 2, Non-Abelian Case

    CERN Document Server

    Wotzasek, C

    1996-01-01

    We study the non-abelian extension of the soldering process of two chiral WZW models of opposite chiralities, resulting in a (non-chiral) WZW model living in a 2D space-time with non trivial Riemanian curvature.

  12. Spiral Galaxies as Chiral Objects?

    CERN Document Server

    Capozziello, S; Capozziello, Salvatore; Lattanzi, Alessandra

    2005-01-01

    Spiral galaxies show axial symmetry and an intrinsic 2D-chirality. Environmental effects can influence the chirality of originally isolated stellar systems and a progressive loss of chirality can be recognised in the Hubble sequence. We point out a preferential modality for genetic galaxies as in microscopic systems like aminoacids, sugars or neutrinos. This feature could be the remnant of a primordial symmetry breaking characterizing systems at all scales.

  13. Chiral Dynamics 2006

    Science.gov (United States)

    Ahmed, Mohammad W.; Gao, Haiyan; Weller, Henry R.; Holstein, Barry

    2007-10-01

    pt. A. Plenary session. Opening remarks: experimental tests of chiral symmetry breaking / A. M. Bernstein. [Double pie symbols] scattering / H. Leutwyler. Chiral effective field theory in a [Triangle]-resonance region / V. Pascalutsa. Some recent developments in chiral perturbation theory / Ulf-G. Mei ner. Chiral extrapolation and nucleon structure from the lattice / R.D. Young. Recent results from HAPPEX / R. Michaels. Chiral symmetries and low energy searches for new physics / M.J. Ramsey-Musolf. Kaon physics: recent experimental progress / M. Moulson. Status of the Cabibbo angle / V. Cirigliano. Lattice QCD and nucleon spin structure / J.W. Negele. Spin sum rules and polarizabilities: results from Jefferson lab / J-P Chen. Compton scattering and nucleon polarisabilities / Judith A. McGovern. Virtual compton scattering at MIT-bates / R. Miskimen. Physics results from the BLAST detector at the BATES accelerator / R.P. Redwine. The [Pie sympbol]NN system, recent progress / C. Hanhart. Application of chiral nuclear forces to light nuclei / A. Nogga. New results on few-body experiments at low energy / Y. Nagai. Few-body lattice calculations / M.J. Savage. Research opportunities at the upgraded HI?S facility / H.R. Weller -- pt. B. Goldstone boson dynamics. Working group summary: Goldstone Boson dynamics / G. Colangelo and S. Giovannella. Recent results on radiative Kaon decays from NA48 and NA48/2 / S.G. López. Cusps in K-->3 [Pie symbol] decays / B. Kubis. Recent KTeV results on radiative Kaon decays / M.C. Ronquest. The [Double pie symbols] scattering amplitude / J.R. Peláez. Determination of the Regge parameters in the [Double pie symbols] scattering amplitude / I. Caprini. e+e- Hadronic cross section measurement at DA[symbol]NE with the KLOE detector / P. Beltrame. Measurement of the form factors of e+e- -->2([Pie symbol]+[Pie symbol]-), pp and the resonant parameters of the heavy charmonia at BES / H. Hu. Measurement of e+e- multihadronic cross section below 4

  14. Chiral Biomarkers in Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-01-01

    The chirality of organic molecules with the asymmetric location of group radicals was discovered in 1848 by Louis Pasteur during his investigations of the rotation of the plane of polarization of light by crystals of sodium ammonium paratartrate. It is well established that the amino acids in proteins are exclusively Levorotary (L-aminos) and the sugars in DNA and RNA are Dextrorotary (D-sugars). This phenomenon of homochirality of biological polymers is a fundamental property of all life known on Earth. Furthermore, abiotic production mechanisms typically yield recemic mixtures (i.e. equal amounts of the two enantiomers). When amino acids were first detected in carbonaceous meteorites, it was concluded that they were racemates. This conclusion was taken as evidence that they were extraterrestrial and produced by abiologically. Subsequent studies by numerous researchers have revealed that many of the amino acids in carbonaceous meteorites exhibit a significant L-excess. The observed chirality is much greater than that produced by any currently known abiotic processes (e.g. Linearly polarized light from neutron stars; Circularly polarized ultraviolet light from faint stars; optically active quartz powders; inclusion polymerization in clay minerals; Vester-Ulbricht hypothesis of parity violations, etc.). This paper compares the measured chirality detected in the amino acids of carbonaceous meteorites with the effect of these diverse abiotic processes. IT is concluded that the levels observed are inconsistent with post-arrival biological contamination or with any of the currently known abiotic production mechanisms. However, they are consistent with ancient biological processes on the meteorite parent body. This paper will consider these chiral biomarkers in view of the detection of possible microfossils found in the Orgueil and Murchison carbonaceous meteorites. Energy dispersive x-ray spectroscopy (EDS) data obtained on these morphological biomarkers will be

  15. Generalized simplicial chiral models

    CERN Document Server

    Alimohammadi, M

    2000-01-01

    Using the auxiliary field representation of the simplicial chiral models on a (d-1)-dimensional simplex, we generalize the simplicial chiral models by replacing the term Tr$(AA^{\\d})$ in the Lagrangian of these models, by an arbitrary class function of $AA^{\\d}; V(AA^{\\d})$. This is the same method that has been used in defining the generalized two-dimensional Yang-Mills theories (gYM_2) from ordinary YM_2. We call these models, the " generalized simplicial chiral models ". With the help of the results of one-link integral over a U(N) matrix, we compute the large-N saddle-point equations for eigenvalue density function $\\ro (z)$ in the weak ($\\b >\\b_c$) and strong ($\\b <\\b_c$) regions. In d=2, where the model somehow relates to gYM_2 theory, we solve the saddle-point equations and find $\\ro (z)$ in two region, and calculate the explicit value of critical point $\\b_c$ for $V(B)=TrB^n (B=AA^{\\d})$. For $V(B)=Tr B^2,Tr B^3$ and Tr$B^4$, we study the critical behaviour of the model at d=2, and by calculating t...

  16. Chiral nuclear thermodynamics

    CERN Document Server

    Fiorilla, Salvatore; Weise, Wolfram

    2011-01-01

    We calculate the equation of state of nuclear matter for arbitrary isospin-asymmetry up to three loop order in the free energy density in the framework of in-medium chiral perturbation theory. In our approach 1\\pi- and 2\\pi-exchange dynamics with the inclusion of the \\Delta-isobar excitation as an explicit degree of freedom, corresponding to the long- and intermediate-range correlations, are treated explicitly. Few contact terms fixed to reproduce selected known properties of nuclear matter encode the short-distance physics. Two-body as well as three-body forces are systematically included. We find a critical temperature of about 15 MeV for symmetric nuclear matter. We investigate the dependence of the liquid-gas first-order phase transition on isospin-asymmetry. In the same chiral framework we calculate the chiral condensate of isospin-symmetric nuclear matter at finite temperatures. The contribution of the \\Delta-isobar excitation is essential for stabilizing the condensate. As a result, we find no indicati...

  17. Free-standing chiral plasmonics

    Science.gov (United States)

    Leong, Eunice Sok Ping; Deng, Jie; Wu, Siji; Khoo, Eng Huat; Liu, Yan Jun

    2014-11-01

    Chiral plasmonic nanostructures offer the ability to achieve strong optical circular dichroism (CD) activity over a broad spectral range, which has been challenging for chiral molecules. Chiral plasmonic nanostructures have been extensively studied based on top-down and bottom-up fabrication techniques. Particularly, in the top-down electron-beam lithography, 3D plasmonic nanostructure fabrication involves layer-by-layer patterning and complex alignment, which is time-consuming and causes many defects in the structures. Here, we present a free-standing 3D chiral plamonic nanostructures using the electron-beam lithography technique with much simplified fabrication processes. The 3D chiral plasmonic nanostructures consist of a free-standing ultrathin silicon nitride membrane with well-aligned L-shape metal nanostructures on one side and disk-shape ones on the other side. The free-standing membrane provides an ultra-smooth metal/dielectric interface and uniformly defines the gap between the upper and lower layers in an array of chiral nanostructures. Such free-standing chiral plasmonic nanostructures exhibit strong CD at optical frequencies, which can be engineered by simply changing the disk size on one side of the membrane. Experimental results are in good agreement with the finite-difference time-domain simulations. Such free-standing chiral plasmonics holds great potential for chirality analysis of biomolecules, drugs, and chemicals.

  18. Chiral nanophotonics chiral optical properties of plasmonic systems

    CERN Document Server

    Schäferling, Martin

    2017-01-01

    This book describes the physics behind the optical properties of plasmonic nanostructures focusing on chiral aspects. It explains in detail how the geometry determines chiral near-fields and how to tailor their shape and strength. Electromagnetic fields with strong optical chirality interact strongly with chiral molecules and, therefore, can be used for enhancing the sensitivity of chiroptical spectroscopy techniques. Besides a short review of the latest results in the field of plasmonically enhanced enantiomer discrimination, this book introduces the concept of chiral plasmonic near-field sources for enhanced chiroptical spectroscopy. The discussion of the fundamental properties of these light sources provides the theoretical basis for further optimizations and is of interest for researchers at the intersection of nano-optics, plasmonics and stereochemistry. .

  19. Isothermal Titration Calorimetry of Chiral Polymeric Nanoparticles.

    Science.gov (United States)

    Werber, Liora; Preiss, Laura C; Landfester, Katharina; Muñoz-Espí, Rafael; Mastai, Yitzhak

    2015-09-01

    Chiral polymeric nanoparticles are of prime importance, mainly due to their enantioselective potential, for many applications such as catalysis and chiral separation in chromatography. In this article we report on the preparation of chiral polymeric nanoparticles by miniemulsion polymerization. In addition, we describe the use of isothermal titration calorimetry (ITC) to measure the chiral interactions and the energetics of the adsorption of enantiomers from aqueous solutions onto chiral polymeric nanoparticles. The characterization of chirality in nano-systems is a very challenging task; here, we demonstrate that ITC can be used to accurately determine the thermodynamic parameters associated with the chiral interactions of nanoparticles. The use of ITC to measure the energetics of chiral interactions and recognition at the surfaces of chiral nanoparticles can be applied to other nanoscale chiral systems and can provide further insight into the chiral discrimination processes of nanomaterials. © 2015 Wiley Periodicals, Inc.

  20. Quark structure of chiral solitons

    CERN Document Server

    Diakonov, D

    2004-01-01

    There is a prejudice that the chiral soliton model of baryons is something orthogonal to the good old constituent quark models. In fact, it is the opposite: the spontaneous chiral symmetry breaking in strong interactions explains the appearance of massive constituent quarks of small size thus justifying the constituent quark models, in the first place. Chiral symmetry ensures that constituent quarks interact very strongly with the pseudoscalar fields. The ``chiral soliton'' is another word for the chiral field binding constituent quarks. We show how the old SU(6) quark wave functions follow from the ``soliton'', however, with computable relativistic corrections and additional quark-antiquark pairs. We also find the 5-quark wave function of the exotic baryon Theta+.

  1. Applications Of Chiral Perturbation Theory

    CERN Document Server

    Mohta, V

    2005-01-01

    Effective field theory techniques are used to describe the spectrum and interactions of hadrons. The mathematics of classical field theory and perturbative quantum field theory are reviewed. The physics of effective field theory and, in particular, of chiral perturbation theory and heavy baryon chiral perturbation theory are also reviewed. The geometry underlying heavy baryon chiral perturbation theory is described in detail. Results by Coleman et. al. in the physics literature are stated precisely and proven. A chiral perturbation theory is developed for a multiplet containing the recently- observed exotic baryons. A small coupling expansion is identified that allows the calculation of self-energy corrections to the exotic baryon masses. Opportunities in lattice calculations are discussed. Chiral perturbation theory is used to study the possibility of two multiplets of exotic baryons mixed by quark masses. A new symmetry constraint on reduced partial widths is identified. Predictions in the literature based ...

  2. Dileptons and Chiral Symmetry Restoration

    CERN Document Server

    Hohler, P M

    2015-01-01

    We report on recent work relating the medium effects observed in dilepton spectra in heavy-ion collisions to potential signals of chiral symmetry restoration. The key connection remains the approach to spectral function degeneracy between the vector-isovector channel with its chiral partner, the axialvector-isovector channel. Several approaches are discussed to elaborate this connection, namely QCD and Weinberg sum rules with input for chiral order parameters from lattice QCD, and chiral hadronic theory to directly evaluate the medium effects of the axialvector channel and the pertinent pion decay constant as function of temperature. A pattern emerges where the chiral mass splitting between rho and a_1 burns off and is accompanied by a strong broadening of the spectral distributions.

  3. Chiral Nuclear Dynamics II

    CERN Document Server

    Rho, Mannque

    2008-01-01

    This is the sequel to the first volume to treat in one effective field theory framework the physics of strongly interacting matter under extreme conditions. This is vital for understanding the high temperature phenomena taking place in relativistic heavy ion collisions and in the early Universe, as well as the high-density matter predicted to be present in compact stars. The underlying thesis is that what governs hadronic properties in a heat bath and/or a dense medium is hidden local symmetry which emerges from chiral dynamics of light quark systems and from the duality between QCD in 4D and

  4. Observing Disoriented Chiral Condensates

    CERN Document Server

    Bjorken, James D; Taylor, C C

    1993-01-01

    We speculate that, in very high energy hadronic collisions, large fireballs may be produced with interiors which have anomalous chiral order parameters. Such a process would result in radiation of pions with distinctive momentum and isospin distributions, and may provide an explanation of Centauro and related phenomena in cosmic-ray events. The phenomenology of such events is reviewed, with emphasis on the possibility of observing such phenomena at Fermilab experiment T-864 (MiniMax), or at a Full Acceptance Detector (FAD) at the SSC.

  5. Spontaneous Chiral Symmetry Breaking as Condensation of Dynamical Chirality

    CERN Document Server

    Alexandru, Andrei

    2012-01-01

    The occurrence of spontaneous chiral symmetry breaking (SChSB) is equivalent to sufficient abundance of Dirac near-zeromodes. However, dynamical mechanism leading to breakdown of chiral symmetry should be naturally reflected in chiral properties of the modes. Here we offer such connection, presenting evidence that SChSB in QCD proceeds via the appearance of modes exhibiting dynamical tendency for local chiral polarization. These modes form a band of finite width Lambda_ch (chiral polarization scale) around the surface of otherwise anti--polarized Dirac sea, and condense. Lambda_ch characterizes the dynamics of the breaking phenomenon and can be converted to a quark mass scale, thus offering conceptual means to determine which quarks of nature are governed by broken chiral dynamics. It is proposed that, within the context of SU(3) gauge theories with fundamental Dirac quarks, mode condensation is equivalent to chiral polarization, making Lambda_ch an "order parameter" of SChSB. Several uses of these features, ...

  6. Repulsive Casimir Force in Chiral Metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, R.; Zhou, J.; Koschny, Th.; Economou, E.N.; Soukoulis, C.M.

    2009-09-04

    We demonstrate theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials. By extending the Lifshitz theory to treat chiral metamaterials, we find that a repulsive force and a minimum of the interaction energy possibly exist for strong chirality, under realistic frequency dependencies and correct limiting values (for zero and infinite frequencies) of the permittivity, permeability, and chiral coefficients.

  7. Repulsive Casimir Force in Chiral Metamaterials

    OpenAIRE

    Zhao, R.; J. Zhou; Koschny, Th.; Economou, E. N.; C M Soukoulis

    2009-01-01

    We demonstrate theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials. By extending the Lifshitz theory to treat chiral metamaterials, we find that a repulsive force and a minimum of the interaction energy exist for strong chirality, under realistic frequency dependencies and correct limiting values (for zero and infinite frequencies) of the permittivity, permeability, and chiral coefficients.

  8. Repulsive Casimir Force in Chiral Metamaterials

    Science.gov (United States)

    Zhao, R.; Zhou, J.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.

    2009-09-01

    We demonstrate theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials. By extending the Lifshitz theory to treat chiral metamaterials, we find that a repulsive force and a minimum of the interaction energy possibly exist for strong chirality, under realistic frequency dependencies and correct limiting values (for zero and infinite frequencies) of the permittivity, permeability, and chiral coefficients.

  9. Nanoscale chirality in metal and semiconductor nanoparticles.

    Science.gov (United States)

    Kumar, Jatish; Thomas, K George; Liz-Marzán, Luis M

    2016-10-18

    The field of chirality has recently seen a rejuvenation due to the observation of chirality in inorganic nanomaterials. The advancements in understanding the origin of nanoscale chirality and the potential applications of chiroptical nanomaterials in the areas of optics, catalysis and biosensing, among others, have opened up new avenues toward new concepts and design of novel materials. In this article, we review the concept of nanoscale chirality in metal nanoclusters and semiconductor quantum dots, then focus on recent experimental and theoretical advances in chiral metal nanoparticles and plasmonic chirality. Selected examples of potential applications and an outlook on the research on chiral nanomaterials are additionally provided.

  10. Nonequilibrium chiral perturbation theory and disoriented chiral condensates

    CERN Document Server

    Nicola, A G

    1999-01-01

    We analyse the extension of Chiral Perturbation Theory to describe a meson gas out of thermal equilibrium. For that purpose, we let the pion decay constant be a time-dependent function and work within the Schwinger-Keldysh contour technique. A useful connection with curved space-time QFT allows to consistently renormalise the model, introducing two new low-energy constants in the chiral limit. We discuss the applicability of our approach within a Relativistic Heavy-Ion Collision environment. In particular, we investigate the formation of Disoriented Chiral Condensate domains in this model, via the parametric resonance mechanism.

  11. Chiral quantum optics.

    Science.gov (United States)

    Lodahl, Peter; Mahmoodian, Sahand; Stobbe, Søren; Rauschenbeutel, Arno; Schneeweiss, Philipp; Volz, Jürgen; Pichler, Hannes; Zoller, Peter

    2017-01-25

    Advanced photonic nanostructures are currently revolutionizing the optics and photonics that underpin applications ranging from light technology to quantum-information processing. The strong light confinement in these structures can lock the local polarization of the light to its propagation direction, leading to propagation-direction-dependent emission, scattering and absorption of photons by quantum emitters. The possibility of such a propagation-direction-dependent, or chiral, light-matter interaction is not accounted for in standard quantum optics and its recent discovery brought about the research field of chiral quantum optics. The latter offers fundamentally new functionalities and applications: it enables the assembly of non-reciprocal single-photon devices that can be operated in a quantum superposition of two or more of their operational states and the realization of deterministic spin-photon interfaces. Moreover, engineered directional photonic reservoirs could lead to the development of complex quantum networks that, for example, could simulate novel classes of quantum many-body systems.

  12. Chiral imbalance in QCD

    Directory of Open Access Journals (Sweden)

    Andrianov Alexander

    2017-01-01

    Full Text Available The chiral imbalance (ChI is given by a difference between the numbers of RH and LH quarks which may occur in the fireball after heavy ion collision. To characterize it adiabatically a quark chiral (axial chemical potential must be introduced taking into account emergence of a ChI in such a phase. In this report the phenomenology of formation of Local spatial Parity Breaking (LPB in the hot and dense baryon matter is discussed and its simulation within a number of QCD-inspired models is outlined. The appearance of new states in the spectra of scalar, pseudoscalar and vector particles in such a matter is elucidated. In particular, from the effective vector meson theory in the presence of Chern-Simons interaction it is demonstrated that the spectrum of massive vector mesons splits into three polarization components with different effective masses. The asymmetry in production of longitudinally and transversely polarized states of ρ and ω mesons for various values of the dilepton invariant mass can serve as a characteristic indication of the LPB in PHENIX, STAR and ALICE experiments.

  13. Chirally extended quantum chromodynamics

    CERN Document Server

    Brower, R C; Tan, C I; Richard C Brower; Yue Shen; Chung-I Tan

    1994-01-01

    We propose an extended Quantum Chromodynamics (XQCD) Lagrangian in which the fermions are coupled to elementary scalar %\\sigma and \\pi fields through a Yukawa coupling which preserves chiral invariance. Our principle motivation is to find a new lattice formulation for QCD which avoids the source of critical slowing down usually encountered as the bare quark mass is tuned to the chiral limit. The phase diagram and the weak coupling limit for XQCD are studied. They suggest a conjecture that the continuum limit of XQCD is the same as the continuum limit of conventional lattice formulation of QCD. As examples of such universality, we present the large N solutions of two prototype models for XQCD, in which the mass of the spurious pion and sigma resonance go to infinity with the cut-off. Even if the universality conjecture turns out to be false, we believe that XQCD will still be useful as a low energy effective action for QCD phenomenology on the lattice. Numerical simulations are recommended to further investiga...

  14. Chiral quantum dot based materials

    Science.gov (United States)

    Govan, Joseph; Loudon, Alexander; Baranov, Alexander V.; Fedorov, Anatoly V.; Gun'ko, Yurii

    2014-05-01

    Recently, the use of stereospecific chiral stabilising molecules has also opened another avenue of interest in the area of quantum dot (QD) research. The main goal of our research is to develop new types of technologically important quantum dot materials containing chiral defects, study their properties and explore their applications. The utilisation of chiral penicillamine stabilisers allowed the preparation of new water soluble white emitting CdS quantum nanostructures which demonstrated circular dichroism in the band-edge region of the spectrum. It was also demonstrated that all three types of QDs (D-, L-, and Rac penicillamine stabilised) show very broad emission bands between 400 and 700 nm due to defects or trap states on the surfaces of the nanocrystals. In this work the chiral CdS based quantum nanostructures have also been doped by copper metal ions and new chiral penicilamine stabilized CuS nanoparticles have been prepared and investigated. It was found that copper doping had a strong effect at low levels in the synthesis of chiral CdS nanostructures. We expect that this research will open new horizons in the chemistry of chiral nanomaterials and their application in biotechnology, sensing and asymmetric synthesis.

  15. [A comment on chiral thin layer chromatography].

    Science.gov (United States)

    Chen, Xuexian; Yuan, Liming

    2016-01-01

    In recent eight years, authors' group has repeated a lot of experiments of chiral thin layer chromatography coming from literature. From the practical opinion, we summarized that there are nine characteristics for chiral thin layer chromatography. Some progresses of chiral thin layer chromatography are reviewed, and the enantioselectivity of a commercial chiral thin layer plate is introduced. The study of vancomycin as the chiral selector in thin layer chromatography is also reported.

  16. Chiral Fermions on the Lattice

    CERN Document Server

    Bietenholz, Wolfgang

    2010-01-01

    In the last century the non-perturbative regularization of chiral fermions was a long-standing problem. We review how this problem was finally overcome by the formulation of a modified but exact form of chiral symmetry on the lattice. This also provides a sound definition of the topological charge of lattice gauge configurations. We illustrate a variety of applications to QCD in the p-, the epsilon- and the delta-regime, where simulation results can now be related to Random Matrix Theory and Chiral Perturbation Theory. The latter contains Low Energy Constants as free parameters, and we comment on their evaluation from first principles of QCD.

  17. Coupling chiral bosons to gravity

    CERN Document Server

    Braga, N R F; Braga, N R F; Wotzasek, C

    1995-01-01

    chiral boson actions of Floreanini and Jackiw (FJ), and of McClain,Wu and Yu (MWY) have been recently shown to be different representations of the same chiral boson theory. MWY displays manifest covariance and also a (gauge) symmetry that is hidden in the FJ side, which, on the other hand, displays the physical spectrum in a simple manner. We make use of the covariance of the MWY representation for the chiral boson to couple it to background gravity showing explicitly the equivalence with the previous results for the FJ representation

  18. Chiral gravity in higher dimensions

    CERN Document Server

    Ootsuka, T; Ura, K; Ootsuka, Takayoshi; Tanaka, Erico; Ura, Kousuke

    2003-01-01

    We construct a chiral theory of gravity in 7 and 8 dimensions, which are equivalent to Einstein-Cartan theory using less variables. In these dimensions, we can construct such higher dimensional chiral gravity because of the existence of gravitational instanton. The octonionic-valued variables in the theory represent the deviation from the gravitational instanton, and from their non-associativity, prevents the theory to be SO(n) gauge invariant. Still the chiral gravity holds G_2 (7-D), and Spin(7) (8-D) gauge symmetry.

  19. Chiral Relaxation Time at the Chiral Crossover of Quantum Chromodynamics

    CERN Document Server

    Ruggieri, M; Chernodub, M

    2016-01-01

    We study microscopic processes responsible for chirality flips in the thermal bath of Quantum Chromodynamics at finite temperature and zero baryon chemical potential. We focus on the temperature range where the crossover from chirally broken phase to quark-gluon plasma takes place, namely $T \\simeq (150, 200)$ MeV. The processes we consider are quark-quark scatterings mediated by collective excitations with the quantum number of pions and $\\sigma$-meson, hence we refer to these processes simply as \\sugg{to} one-pion (one-$\\sigma$) exchange\\sugg{s}. We use a Nambu-Jona-Lasinio model to compute equilibrium properties of the thermal bath, as well as the relevant scattering kernel to be used in the collision integral to estimate the chiral relaxation time $\\tau$. We find $\\tau\\simeq 0.1 \\div 1$ fm/c around the chiral crossover.

  20. Consistent chiral kinetic theory in Weyl materials: chiral magnetic plasmons

    CERN Document Server

    Gorbar, E V; Shovkovy, I A; Sukhachov, P O

    2016-01-01

    We argue that the correct definition of the electric current in the chiral kinetic theory for Weyl materials should include the Chern--Simons contribution that makes the theory consistent with the local conservation of the electric charge in electromagnetic and strain-induced pseudoelectromagnetic fields. By making use of such a kinetic theory, we study the plasma frequencies of collective modes in Weyl materials in constant magnetic and pseudomagnetic fields taking into account the effects of dynamical electromagnetism. We show that the collective modes are chiral plasmons. While the plasma frequency of the longitudinal collective mode coincides with the Langmuir one, this mode is unusual because it is characterized not only by oscillations of the electric current density, but also oscillations of the chiral current density. The latter are triggered by a dynamical version of the chiral electric separation effect. We also find that the plasma frequencies of the transverse modes split up in a magnetic field. T...

  1. Field induced spin chirality and chirality switching in magnetic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tartakovskaya, Elena V., E-mail: elena_tartakovskaya@yahoo.com [Institute of Magnetism NAS of Ukraine, Vernadsky blvd 36b, 03142 Kiev (Ukraine); Institute of High Technologies, Taras Shevchenko National University of Kiev, 03022 Kiev (Ukraine)

    2015-05-01

    The physical origin of the field-induced spin chirality experimentally observed in rare earth multilayers is determined. It is shown that the effect is possible due to the interplay between solid-state exchange interactions (the Ruderman–Kittel–Kasuya–Yosida and the Dsyaloshinsky–Moriya interactions), the external magnetic field and a special confinement of magnetic constituents. The presented model describes a certain temperature dependence of the chirality factor in agreement with experimental data and opens a new way to design nanostructured objects with predicted handedness. - Highlights: • Field-induced spin chirality in magnetic multilayers is explained. • The roles of the RKKY, the DM and the Zeeman interactions are clarified. • Theoretical analysis of the chirality factor is in agreement with experimental data.

  2. Reducible chiral metamaterials

    CERN Document Server

    Ciattoni, Alessandro; Rizza, Carlo

    2016-01-01

    We introduce the concept of 3D reducible metamaterials whose constituent permittivity can be modelled by a factorized profile. The separated cartesian coordinates dependence, easily achieved in all-optical reconfigurable materials, allows to physically regard a reducible metamaterial as a superposition of three fictitious 1D generating media. We prove that, in the long-wavelength limit, the electromagnetic response of reducible metamaterials can be reconstructed from the properties of the 1D generating media whose interplay provides large freedom to control the electromagnetic chirality. Our approach introduces an unprecedented decomposition strategy in metamaterial science which allows the full ab-initio and flexible design of a complex 3D bianisotropic response by using 1D metamaterials as basic building blocks.

  3. Chirality in photonic systems

    Science.gov (United States)

    Solnyshkov, Dmitry; Malpuech, Guillaume

    2016-10-01

    The optical modes of photonic structures are the so-called TE and TM modes that bring intrinsic spin-orbit coupling and chirality to these systems. This, combined with the unique flexibility of design of the photonic potential, and the possibility to mix photon states with excitonic resonances, sensitive to magnetic field and interactions, allows us to achieve many phenomena, often analogous to other solid-state systems. In this contribution, we review in a qualitative and comprehensive way several of these realizations, namely the optical spin Hall effect, the creation of spin currents protected by a non-trivial geometry, the Berry curvature for photons, and the photonic/polaritonic topological insulator.

  4. Amino Acids and Chirality

    Science.gov (United States)

    Cook, Jamie E.

    2012-01-01

    Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

  5. Chiral Dynamics With Wilson Fermions

    CERN Document Server

    Splittorff, K

    2012-01-01

    Close to the continuum the lattice spacing affects the smallest eigenvalues of the Wilson Dirac operator in a very specific manner determined by the way in which the discretization breaks chiral symmetry. These effects can be computed analytically by means of Wilson chiral perturbation theory and Wilson random matrix theory. A number of insights on chiral Dynamics with Wilson fermions can be obtained from the computation of the microscopic spectrum of the Wilson Dirac operator. For example, the unusual volume scaling of the smallest eigenvalues observed in lattice simulations has a natural explanation. The dynamics of the eigenvalues of the Wilson Dirac operator also allow us to determine the additional low energy constants of Wilson chiral perturbation theory and to understand why the Sharpe-Singleton scenario is only realized in unquenched simulations.

  6. Domains of Disoriented Chiral Condensate

    CERN Document Server

    Amado, R D; Lu, Yang

    1996-01-01

    The probability distribution of neutral pion fraction from independent domains of disoriented chiral condensate is characterized. The signal for the condensate is clear for a small number of domains but is greatly reduced for more than three.

  7. Chiral Quark Model of Mesons

    CERN Document Server

    Wang, X J; Wang, Xiao-Jun; Yan, Mu-Lin

    1999-01-01

    We study SU(3)$_L\\timesSU(3)_R$ chiral quark model of mesons up to next leading order of $1/N_c$ expansion. Composite vector and axial-vector mesons resonances are introduced via non-linear realization of chiral SU(3) and vector meson dominant. Effects of one-loop graphs of pseudoscalar, vector and axial-vector mesons is calculated systematically and the significant results are obtained. Correction of effective gluon interaction is studied too. The light quark masses are introduced via new mechanism which agree with phenomenology and the requirement of chiral symmetry. Up to powers four of derivatives, chiral effective lagrangian of mesons is derived and evaluated to next leading order of $1/N_c$. Low energy limit of the model is examined. Ten low energy coupling constants $L_i(i=1,2,...,10)$ in ChPT are obtained and agree with ChPT well.

  8. Chirally motivated K - nuclear potentials

    Science.gov (United States)

    Cieplý, A.; Friedman, E.; Gal, A.; Gazda, D.; Mareš, J.

    2011-08-01

    In-medium subthreshold Kbar N scattering amplitudes calculated within a chirally motivated meson-baryon coupled-channel model are used self consistently to confront K- atom data across the periodic table. Substantially deeper K- nuclear potentials are obtained compared to the shallow potentials derived in some approaches from threshold Kbar N amplitudes, with Re VK-chiral = - (85 ± 5) MeV at nuclear matter density. When Kbar NN contributions are incorporated phenomenologically, a very deep K- nuclear potential results, Re VK-chiral + phen . = - (180 ± 5) MeV, in agreement with density dependent potentials obtained in purely phenomenological fits to the data. Self consistent dynamical calculations of K--nuclear quasibound states generated by VK-chiral are reported and discussed.

  9. Review of chiral perturbation theory

    Indian Academy of Sciences (India)

    B Ananthanarayan

    2003-11-01

    A review of chiral perturbation theory and recent developments on the comparison of its predictions with experiment is presented. Some interesting topics with scope for further elaboration are touched upon.

  10. Meta-Chirality: Fundamentals, Construction and Applications

    Directory of Open Access Journals (Sweden)

    Xiaoliang Ma

    2017-05-01

    Full Text Available Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced.

  11. Meta-Chirality: Fundamentals, Construction and Applications

    Science.gov (United States)

    Ma, Xiaoliang; Pu, Mingbo; Li, Xiong; Guo, Yinghui; Gao, Ping; Luo, Xiangang

    2017-01-01

    Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced. PMID:28513560

  12. Homogenization of resonant chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Menzel, C.; Rockstuhl, Carsten

    2010-01-01

    Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as, e.g., propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size...... an analytical criterion for performing the homogenization and a tool to predict the homogenization limit. We show that strong coupling between meta-atoms of chiral metamaterials may prevent their homogenization at all....

  13. Homogenization of resonant chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Menzel, C.; Rockstuhl, Carsten

    2010-01-01

    Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as, e.g., propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size...... an analytical criterion for performing the homogenization and a tool to predict the homogenization limit. We show that strong coupling between meta-atoms of chiral metamaterials may prevent their homogenization at all....

  14. Chiral thermodynamics of nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Fiorilla, Salvatore

    2012-10-23

    The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

  15. Baryon spectrum and chiral dynamics

    CERN Document Server

    Glozman, L Ya

    1995-01-01

    New results on baryon structure and spectrum developed in collaboration with Dan Riska [1-4] are reported. The main idea is that beyond the chiral symmetry spontaneous breaking scale light and strange baryons should be considered as systems of three constituent quarks with an effective confining interaction and a chiral interaction that is mediated by the octet of Goldstone bosons (pseudoscalar mesons) between the constituent quarks.

  16. Bottom-up synthesis of chiral covalent organic frameworks and their bound capillaries for chiral separation.

    Science.gov (United States)

    Qian, Hai-Long; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2016-07-12

    Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.

  17. Bottom-up synthesis of chiral covalent organic frameworks and their bound capillaries for chiral separation

    Science.gov (United States)

    Qian, Hai-Long; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2016-07-01

    Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.

  18. Chirality in Bare and Passivated Gold Nanoclusters

    CERN Document Server

    Garzon, I L; Rodrigues-Hernandez, J I; Sigal, I; Beltran, M R; Michaelian, K

    2002-01-01

    Chiral structures have been found as the lowest-energy isomers of bare (Au$_{28}$ and Au$_{55}) and thiol-passivated (Au$_{28}(SCH$_{3})$_{16}$ and Au$_{38}$(SCH$_{3}$)$_{24}) gold nanoclusters. The degree of chirality existing in the chiral clusters was calculated using the Hausdorff chirality measure. We found that the index of chirality is higher in the passivated clusters and decreases with the cluster size. These results are consistent with the observed chiroptical activity recently reported for glutahione-passivated gold nanoclusters, and provide theoretical support for the existence of chirality in these novel compounds.

  19. Using the Chiral Organophosphorus Derivatizing Agents for Determination of the Enantiomeric Composition of Chiral Carboxylic Acids by 31PNMR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Chao CHE; Zhong Ning ZHANG; Gui Lan HUANG; Xin Xing WANG; Zhao Hai QIN

    2004-01-01

    The use of chiral organophosphorus derivatizing agents prepared in situ from chiral tartrate or chiral diamine for the 31PNMR determination of the enantiomeric composition of chiral carboxylic acids is described. The method is accurate, reliable and convenient.

  20. Consistent Chiral Kinetic Theory in Weyl Materials: Chiral Magnetic Plasmons

    Science.gov (United States)

    Gorbar, E. V.; Miransky, V. A.; Shovkovy, I. A.; Sukhachov, P. O.

    2017-03-01

    We argue that the correct definition of the electric current in the chiral kinetic theory for Weyl materials should include the Chern-Simons contribution that makes the theory consistent with the local conservation of the electric charge in electromagnetic and strain-induced pseudoelectromagnetic fields. By making use of such a kinetic theory, we study the plasma frequencies of collective modes in Weyl materials in constant magnetic and pseudomagnetic fields, taking into account the effects of dynamical electromagnetism. We show that the collective modes are chiral plasmons. While the plasma frequency of the longitudinal collective mode coincides with the Langmuir one, this mode is unusual because it is characterized not only by oscillations of the electric current density, but also by oscillations of the chiral current density. The latter are triggered by a dynamical version of the chiral electric separation effect. We also find that the plasma frequencies of the transverse modes split up in a magnetic field. This finding suggests an efficient means of extracting the chiral shift parameter from the measurement of the plasma frequencies in Weyl materials.

  1. An Inherent Chiral Calix[4]arene Bearing Chiral Groups without Forming Sub-ring

    Institute of Scientific and Technical Information of China (English)

    Xian Xian LIU; Yan Song ZHENG; Wan Ling MO

    2006-01-01

    The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes bearing optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the interaction of the two chiral groups, which hinder the substituents' free rotation. Thus, these chiral calix[4]arenes display good chiral recognition ability.

  2. Can a Non-Chiral Object Be Made of Two Identical Chiral Moieties?

    Science.gov (United States)

    LeMarechal, Jean Francois

    2008-01-01

    Several pedagogical objects can be used to discuss chirality. Here, we use the cut of an apple to show that the association of identical chiral moieties can form a non-chiral object. Octahedral chirality is used to find situations equivalent to the cut of the apple. (Contains 5 figures.)

  3. Chaos of chiral condensate

    CERN Document Server

    Hashimoto, Koji; Yoshida, Kentaroh

    2016-01-01

    Assigning a chaos index for vacua of generic quantum field theories is a challenging problem. We find chaotic behavior of chiral condensates of a quantum gauge theory at strong coupling limit, by using the AdS/CFT correspondence. We evaluate the time evolution of homogeneous quark condensates and in an N=2 supersymmetric QCD with the SU(N_c) gauge group at large N_c and at large 't Hooft coupling lambda. At an equivalent classical gravity picture, a Lyapunov exponent is readily defined. We show that the condensates exhibit chaotic behavior for energy density E > (6x10^2) (N_c/lambda^2) (m_q)^4 where m_q is the quark mass. The energy region of the chaotic vacua of the N=2 supersymmetric QCD increases for smaller N_c or larger lambda. The Lyapunov exponent is calculated as a function of the theory (N_c,lambda,E), showing that the N=2 supersymmetric QCD is more chaotic for smaller N_c.

  4. Chiral Thirring–Wess model

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Anisur, E-mail: anisur.rahman@saha.ac.in

    2015-10-15

    The vector type of interaction of the Thirring–Wess model was replaced by the chiral type and a new model was presented which was termed as chiral Thirring–Wess model in Rahaman (2015). The model was studied there with a Faddeevian class of regularization. Few ambiguity parameters were allowed there with the apprehension that unitarity might be threatened like the chiral generation of the Schwinger model. In the present work it has been shown that no counter term containing the regularization ambiguity is needed for this model to be physically sensible. So the chiral Thirring–Wess model is studied here without the presence of any ambiguity parameter and it has been found that the model not only remains exactly solvable but also does not lose the unitarity like the chiral generation of the Schwinger model. The phase space structure and the theoretical spectrum of this new model have been determined in the present scenario. The theoretical spectrum is found to contain a massive boson with ambiguity free mass and a massless boson.

  5. Chiral Logs in Quenched QCD

    CERN Document Server

    Dong, S J; Horváth, I; Lee, F X; Liu, K F; Mathur, N; Zhang, J B

    2003-01-01

    The quenched chiral logs are examined on a $16^3 \\times 28$ lattice with Iwasaki gauge action and overlap fermions. The pion decay constant $f_{\\pi}$ is used to set the lattice spacing, $a = 0.200(3)$ fm. With pion mass as low as $\\sim 180 {\\rm MeV}$, we see the quenched chiral logs clearly in $m_{\\pi}^2/m$ and $f_P$, the pseudoscalar decay constant. We analyze the data to determine how low the pion mass needs to be in order for the quenched one-loop chiral perturbation theory ($\\chi$PT) to apply. With the constrained curve fitting, we are able to extract the quenched chiral log parameter $\\delta$ together with the chiral cutoff $\\Lambda_{\\chi}$ and other parameters. Only for $m_{\\pi} \\leq 300 {\\rm MeV}$ do we obtain a consistent and stable fit with a constant $\\delta$ which we determine to be 0.23(2). By comparing to the $12^3 \\times 28$ lattice, we estimate the finite volume effect to be about 1.8% for the smallest pion mass. We also study the quenched non-analytic terms in the nucleon and the $\\rho$ masses...

  6. Orientation-dependent handedness and chiral design

    OpenAIRE

    Efrati, Efi; Irvine, William T. M.

    2013-01-01

    Chirality occupies a central role in fields ranging from biological self-assembly to the design of optical metamaterials. The definition of chirality, as given by Lord Kelvin, associates chirality with the lack of mirror symmetry: the inability to superpose an object on its mirror image. While this definition has guided the classification of chiral objects for over a century, the quantification of handed phenomena based on this definition has proven elusive, if not impossible, as manifest in ...

  7. Chiral gap effect in curved space

    CERN Document Server

    Flachi, Antonino

    2014-01-01

    We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

  8. Chirality: a relational geometric-physical property.

    Science.gov (United States)

    Gerlach, Hans

    2013-11-01

    The definition of the term chirality by Lord Kelvin in 1893 and 1904 is analyzed by taking crystallography at that time into account. This shows clearly that chirality is a relational geometric-physical property, i.e., two relations between isometric objects are possible: homochiral or heterochiral. In scientific articles the relational term chirality is often mistaken for the two valued measure for the individual (absolute) sense of chirality, an arbitrary attributive term.

  9. Bifurcated, modular syntheses of chiral annulet triazacyclononanes.

    Science.gov (United States)

    Argouarch, Gilles; Stones, Graham; Gibson, Colin L; Kennedy, Alan R; Sherrington, David C

    2003-12-21

    Three chiral 2,6-disubstituted tri-N-methyl azamacrocycles have been prepared by modular methods. These macrocycles were accessed from three chiral 1,4,7-triazaheptanes intermediates that were prepared by two independent routes. The first of these routes involved the benzylamine opening of chiral tosyl aziridines followed by debenzylation but was problematic on solubility grounds. A second, more effective, route was developed which avoided debenzylation by using ammonia in the nucleophilic opening of chiral tosyl aziridines.

  10. Chiral Decomposition For Non-Abelian Bosons

    CERN Document Server

    Braga, N R F; Braga, Nelson R. F.; Wotzasek, Clovis

    1996-01-01

    We study the non-abelian extension for the splitting of a scalar field into chiral components. Using this procedure we find a non ambiguous way of coupling a non abelian chiral scalar field to gravity. We start with a (non-chiral) WZW model covariantly coupled to a background metric and, after the splitting, arrive at two chiral Wess-Zumino-Witten (WZW) models coupled to gravity.

  11. On the Biological Advantage of Chirality

    OpenAIRE

    1999-01-01

    The presence of chirality in the main molecules of life may well be not just a structural artifact, but of pure biological advantage. The possibility of the existence of a phenomenon of a special mode of interaction, labeled as "chiral interaction" (CI), for which structural chirality is a necessary condition, is the main reason for such an advantage. In order to demonstrate such a possibility, macroscopic chiral devices are introduced and presented as analogies for such an interaction. For t...

  12. Chiral dynamics of baryons in the perturbative chiral quark model

    Energy Technology Data Exchange (ETDEWEB)

    Pumsa-ard, K.

    2006-07-01

    In this work we develop and apply variants of a perturbative chiral quark model (PCQM) to the study of baryonic properties dominantly in the low-energy region. In a first step we consider a noncovariant form of the PCQM, where confinement is modelled by a static, effective potential and chiral corrections are treated to second order, in line with similar chiral quark models. We apply the PCQM to the study of the electromagnetic form factors of the baryon octet. We focus in particular on the low-energy observables such as the magnetic moments, the charge and magnetic radii. In addition, the electromagnetic N-delta transition is also studied in the framework of the PCQM. In the chiral loop calculations we consider a quark propagator, which is restricted to the quark ground state, or in hadronic language to nucleon and delta intermediate states, for simplicity. We furthermore include the low-lying excited states to the quark propagator. In particular, the charge radius of the neutron and the transverse helicity amplitudes of the N-delta transition are considerably improved by this additional effect. In a next step we develop a manifestly Lorentz covariant version of the PCQM, where in addition higher order chiral corrections are included. The full chiral quark Lagrangian is motivated by and in analogy to the one of Chiral Perturbation Theory (ChPT). This Lagrangian contains a set of low energy constants (LECs), which are parameters encoding short distance effects and heavy degrees of freedom. We evaluate the chiral Lagrangian to order O(p{sup 4}) and to one loop to generate the dressing of the bare quark operators by pseudoscalar mesons. In addition we include the vector meson degrees of freedom in our study. Projection of the dressed quark operators on the baryonic level serves to calculate the relevant matrix elements. In a first application of this scheme, we resort to a parameterization of the valence quark form factors in the electromagnetic sector. Constraints

  13. Field induced spin chirality and chirality switching in magnetic multilayers

    Science.gov (United States)

    Tartakovskaya, Elena V.

    2015-05-01

    The physical origin of the field-induced spin chirality experimentally observed in rare earth multilayers is determined. It is shown that the effect is possible due to the interplay between solid-state exchange interactions (the Ruderman-Kittel-Kasuya-Yosida and the Dsyaloshinsky-Moriya interactions), the external magnetic field and a special confinement of magnetic constituents. The presented model describes a certain temperature dependence of the chirality factor in agreement with experimental data and opens a new way to design nanostructured objects with predicted handedness.

  14. Neutrino Oscillation Induced by Chiral Phase Transition

    Institute of Scientific and Technical Information of China (English)

    MU Cheng-Fu; SUN Gao-Feng; ZHUANG Peng-Fei

    2009-01-01

    Electric charge neutrality provides a relationship between chiral dynamics and neutrino propagation in compact stars.Due to the sudden drop of the electron density at the first-order chiral phase transition,the oscillation for low energy neutrinos is significant and can be regarded as a signature of chiral symmetry restoration in the core of compact stars.

  15. Quenched Chiral Perturbation Theory to one loop

    NARCIS (Netherlands)

    Colangelo, G.; Pallante, E.

    1998-01-01

    The divergences of the generating functional of quenched Chiral Perturbation theory (qCHPT) to one loop are computed in closed form. We show how the quenched chiral logarithms can be reabsorbed in the renormalization of the B0 parameter of the leading order Lagrangian. Finally, we do the chiral powe

  16. Shear Viscosity of Turbulent Chiral Plasma

    CERN Document Server

    Kumar, Avdhesh; Das, Amita; Kaw, P K

    2016-01-01

    It is well known that the difference between the chemical potentials of left-handed and right-handed particles in a parity violating (chiral) plasma can lead to an instability. We show that the chiral instability may drive turbulent transport. Further we estimate the anomalous viscosity of chiral plasma arising from the enhanced collisionality due to turbulence.

  17. Exact Chiral Symmetry on the Lattice

    CERN Document Server

    Neuberger, H

    2001-01-01

    Developments during the last eight years have refuted the folklore that chiral symmetries cannot be preserved on the lattice. The mechanism that permits chiral symmetry to coexist with the lattice is quite general and may work in Nature as well. The reconciliation between chiral symmetry and the lattice is likely to revolutionize the field of numerical QCD.

  18. Synthetic Applications of Chiral Furanboronate

    Institute of Scientific and Technical Information of China (English)

    CHAN; KinFai

    2001-01-01

    We recently uncovered that consecutive reactions of chiral furfural-boronate 1 with a lithium alkoxide and a nucleophile led to the formation of alcohols 2 with good diastereoselection in favor of S-configuration at the newly generated chiral carbon. In addition, it was also found that 2a and 2b were chromatographically separable on a silica gel column. This reaction is believed to involve a tetrahedral borate intermediate, as can be substantiated by 11BNMR spectroscopic studies. Chiral furanmethanolboronates 2a(or 2b) underwent a palladium-catalyzed Suzuki coupling to form enantiomerically pure furans 3, which can be further converted to the synthetically useful hydroxypyranones 4.1,2,3 In addition, Mukaiyama reaction of 1 also led to chromatographically separable diastereomeric aldol-products. The scope and limitation of these conversions will be discussed.  ……

  19. Chiral separation of agricultural fungicides.

    Science.gov (United States)

    Pérez-Fernández, Virginia; García, Maria Ángeles; Marina, Maria Luisa

    2011-09-23

    Fungicides are very important and diverse environmental and agricultural concern species. Their determination in commercial formulations or environmental matrices, requires highly efficient, selective and sensitive methods. A significant number of these chemicals are chiral with the activity residing usually in one of the enantiomers. The different toxicological and degradation behavior observed in many cases for fungicide enantiomers, results in the need to investigate them separately. For this purpose, separation techniques such as GC, HPLC, supercritical fluid chromatography (SFC) and CE have widely been employed although, at present, HPLC still dominates chromatographic chiral analysis of fungicides. This review covers the literature concerning the enantiomeric separation of fungicides usually employed in agriculture grouping the chiral separation methodologies developed for their analysis in environmental, biological, and food samples.

  20. Chirality and gravitational parity violation.

    Science.gov (United States)

    Bargueño, Pedro

    2015-06-01

    In this review, parity-violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long-range spin-dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short-range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity-violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented.

  1. Chiral cardiovascular drugs: an overview.

    Science.gov (United States)

    Ranade, Vasant V; Somberg, John C

    2005-01-01

    Stereochemistry in drug molecules is rapidly becoming an important aspect in drug research, design, and development. Recently, individual stereoisomers of drug molecules with asymmetric centers such as fexofenadine, cetirizine, verapamil, fluoxetine, levalbutarol, and amphetamine, for example, have been separated and developed as individual drugs. These stereoisomers have different therapeutic activity, and each isomer has contributed differently with respect to its formulation's pharmacologic activity, side effects, and toxicity. The present overview discusses chirality among a select group of cardiovascular drugs, their stereochemical synthesis/preparation, isolation techniques using chiral chromatography, methods for confirmation of their enantiomeric purity, pharmacodynamics, and pharmacokinetics. Chirality has been visualized as an important factor in cardiovascular research. It is also becoming evident in other areas of therapeutics.

  2. Synthetic Applications of Chiral Furanboronate

    Institute of Scientific and Technical Information of China (English)

    CHAN KinFai; WONG Henry N,C.

    2001-01-01

    @@ We recently uncovered that consecutive reactions of chiral furfural-boronate 1 with a lithium alkoxide and a nucleophile led to the formation of alcohols 2 with good diastereoselection in favor of S-configuration at the newly generated chiral carbon. In addition, it was also found that 2a and 2b were chromatographically separable on a silica gel column. This reaction is believed to involve a tetrahedral borate intermediate, as can be substantiated by 11BNMR spectroscopic studies. Chiral furanmethanolboronates 2a(or 2b) underwent a palladium-catalyzed Suzuki coupling to form enantiomerically pure furans 3, which can be further converted to the synthetically useful hydroxypyranones 4.1,2,3 In addition, Mukaiyama reaction of 1 also led to chromatographically separable diastereomeric aldol-products. The scope and limitation of these conversions will be discussed.

  3. Strange chiral nucleon form factors

    CERN Document Server

    Hemmert, T R; Meißner, Ulf G; Hemmert, Thomas R.; Kubis, Bastian; Meissner, Ulf-G.

    1999-01-01

    We investigate the strange electric and magnetic form factors of the nucleon in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. All counterterms can be fixed from data. In particular, the two unknown singlet couplings can be deduced from the parity-violating electron scattering experiments performed by the SAMPLE and the HAPPEX collaborations. Within the given uncertainties, our analysis leads to a small and positive electric strangeness radius, $ = (0.05 \\pm 0.16) fm^2$. We also deduce the consequences for the upcoming MAMI A4 experiment.

  4. Asymmetric Synthesis via Chiral Aziridines

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Harden, Adrian; Wyatt, Paul

    1996-01-01

    A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b......A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines...

  5. Collisions in Chiral Kinetic Theory

    CERN Document Server

    Chen, Jing-Yuan; Stephanov, Mikhail A

    2015-01-01

    Using a covariant formalism, we construct a chiral kinetic theory Lorentz invariant to order $\\mathcal O(\\hbar)$ which includes collisions. We find a new contribution to the particle number current due to the side jumps required by the conservation of angular momentum during collisions. We also find a conserved symmetric stress-energy tensor as well as the $H$-function obeying Boltzmann's $H$-theorem. We demonstrate their use by finding a general equilibrium solution and the values of the anomalous transport coefficients characterizing chiral vortical effect.

  6. Novel Chiral Auxiliaries of BIAZOLs

    Institute of Scientific and Technical Information of China (English)

    CHEN; Arh-Hwang

    2001-01-01

    Asymmetric catalysis is one of the most challenging and formidable endeavor in organic synthesis. The development of chiral auxiliaries is a key in the asymmetric catalysis. Azulenoids, a parent structure of bicyclo[5.3.0]decapentaene with 10 πelectrons, are useful as dye materials, medical treatment of inflammation and hypertension, and the development of liquid crystals. In continuing to investigate synthetic application of azulenoids, we have studied to develop novel chiral auxiliaries of BIAZOLs. The BIAZOLs were synthesized from dicyclopentadiene and characterized using spectroscopies.  ……

  7. Novel Chiral Auxiliaries of BIAZOLs

    Institute of Scientific and Technical Information of China (English)

    CHEN Arh-Hwang; YUAN Shou-Bin; CHIU Shu-Ching

    2001-01-01

    @@ Asymmetric catalysis is one of the most challenging and formidable endeavor in organic synthesis. The development of chiral auxiliaries is a key in the asymmetric catalysis. Azulenoids, a parent structure of bicyclo[5.3.0]decapentaene with 10 πelectrons, are useful as dye materials, medical treatment of inflammation and hypertension, and the development of liquid crystals. In continuing to investigate synthetic application of azulenoids, we have studied to develop novel chiral auxiliaries of BIAZOLs. The BIAZOLs were synthesized from dicyclopentadiene and characterized using spectroscopies.

  8. Dynamic chirality, chirality transfer and aggregation behaviour of dithienylethene switches

    NARCIS (Netherlands)

    de Jong, Jaap J. D.; van Rijn, Patrick; Tiemersma-Wegeman, Theodora D.; Lucas, Linda N.; Browne, Wesley R.; Kellogg, Richard M.; Uchida, Kingo; Van Esch, Jan H.; Feringa, Ben L.

    2008-01-01

    The synthesis and characterisation of a series of chiral and achiral low molecular weight organogelators (LMWGs) based on bis-amide substituted dithienylethene photochromic switches is reported. The LMWGs gelate a range of solvents depending on the specific functionalisation of the hydrogen bonding

  9. K stability and stability of chiral ring

    CERN Document Server

    Collins, Tristan C; Yau, Shing-Tung

    2016-01-01

    We define a notion of stability for chiral ring of four dimensional N=1 theory by introducing test chiral rings and generalized a maximization. We conjecture that a chiral ring is the chiral ring of a superconformal field theory if and only if it is stable. We then study N=1 field theory derived from D3 branes probing a three-fold singularity X, and show that the K stability which implies the existence of Ricci-flat conic metric on X is equivalent to the stability of chiral ring of the corresponding field theory.

  10. Thermal chiral vortical and magnetic waves: new excitation modes in chiral fluids

    CERN Document Server

    Kalaydzhyan, Tigran

    2016-01-01

    In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark-gluon plasma, liquid helium 3He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in a external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density, the chiral vortical and chiral magnetic waves. We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the excitation reduces to a charge diffusion mode or is completely absent. We also correct the dispersion relation for the chiral magnetic wave.

  11. Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate

    Science.gov (United States)

    Jiang, Wenge; Pacella, Michael S.; Athanasiadou, Dimitra; Nelea, Valentin; Vali, Hojatollah; Hazen, Robert M.; Gray, Jeffrey J.; McKee, Marc D.

    2017-04-01

    Chirality is ubiquitous in biology, including in biomineralization, where it is found in many hardened structures of invertebrate marine and terrestrial organisms (for example, spiralling gastropod shells). Here we show that chiral, hierarchically organized architectures for calcium carbonate (vaterite) can be controlled simply by adding chiral acidic amino acids (Asp and Glu). Chiral, vaterite toroidal suprastructure having a `right-handed' (counterclockwise) spiralling morphology is induced by L-enantiomers of Asp and Glu, whereas `left-handed' (clockwise) morphology is induced by D-enantiomers, and sequentially switching between amino-acid enantiomers causes a switch in chirality. Nanoparticle tilting after binding of chiral amino acids is proposed as a chiral growth mechanism, where a `mother' subunit nanoparticle spawns a slightly tilted, consequential `daughter' nanoparticle, which by amplification over various length scales creates oriented mineral platelets and chiral vaterite suprastructures. These findings suggest a molecular mechanism for how biomineralization-related enantiomers might exert hierarchical control to form extended chiral suprastructures.

  12. Chiral magnetic plasmons in anomalous relativistic matter

    CERN Document Server

    Gorbar, E V; Shovkovy, I A; Sukhachov, P O

    2016-01-01

    The chiral plasmon modes of relativistic matter in background magnetic and strain-induced pseudomagnetic fields are studied in detail using the consistent chiral kinetic theory. The results reveal a number of anomalous features of these chiral magnetic and pseudomagnetic plasmons that could be used to identify them in experiment. In a system with nonzero electric (chiral) chemical potential, the background magnetic (pseudomagnetic) fields not only modify the values of the plasmon frequencies in the long wavelength limit, but also affect the qualitative dependence on the wave-vector. Similar modifications can be also induced by the chiral shift parameter in Weyl materials. Interestingly, even in the absence of the chiral shift and external fields, the chiral chemical potential alone leads to a splitting of plasmon energies at linear order in the wave vector.

  13. Algebraic study of chiral anomalies

    Indian Academy of Sciences (India)

    Juan Mañes; Raymond Stora; Bruno Zumino

    2012-06-01

    The algebraic structure of chiral anomalies is made globally valid on non-trivial bundles by the introduction of a fixed background connection. Some of the techniques used in the study of the anomaly are improved or generalized, including a systematic way of generating towers of ‘descent equations’.

  14. Single chirality through crystal grinding

    NARCIS (Netherlands)

    Noorduin, W.L.

    2010-01-01

    The properties of chiral molecules in living organisms can be different for left- and right-handed molecules. Therefore, ways to produce molecules of single handedness are of paramount importance, especially for economical, high yielding processes to synthesize pharmaceutical compounds that must be

  15. Chiral Perturbation Theory and Unitarization

    CERN Document Server

    Ruiz-Arriola, E; Nieves, J; Peláez, J R

    2000-01-01

    We review our recent work on unitarization and chiral perturbation theory both in the $\\pi\\pi$ and the $\\pi N$ sectors. We pay particular attention to the Bethe-Salpeter and Inverse Amplitude unitarization methods and their recent applications to $\\pi\\pi$ and $\\pi N$ scattering.

  16. Nuclear chiral dynamics and thermodynamics

    Science.gov (United States)

    Holt, Jeremy W.; Kaiser, Norbert; Weise, Wolfram

    2013-11-01

    This presentation reviews an approach to nuclear many-body systems based on the spontaneously broken chiral symmetry of low-energy QCD. In the low-energy limit, for energies and momenta small compared to a characteristic symmetry breaking scale of order 1 GeV, QCD is realized as an effective field theory of Goldstone bosons (pions) coupled to heavy fermionic sources (nucleons). Nuclear forces at long and intermediate distance scales result from a systematic hierarchy of one- and two-pion exchange processes in combination with Pauli blocking effects in the nuclear medium. Short distance dynamics, not resolved at the wavelengths corresponding to typical nuclear Fermi momenta, are introduced as contact interactions between nucleons. Apart from a set of low-energy constants associated with these contact terms, the parameters of this theory are entirely determined by pion properties and low-energy pion-nucleon scattering observables. This framework (in-medium chiral perturbation theory) can provide a realistic description of both isospin-symmetric nuclear matter and neutron matter, with emphasis on the isospin-dependence determined by the underlying chiral NN interaction. The importance of three-body forces is emphasized, and the role of explicit Δ(1232)-isobar degrees of freedom is investigated in detail. Nuclear chiral thermodynamics is developed and a calculation of the nuclear phase diagram is performed. This includes a successful description of the first-order phase transition from a nuclear Fermi liquid to an interacting Fermi gas and the coexistence of these phases below a critical temperature Tc. Density functional methods for finite nuclei based on this approach are also discussed. Effective interactions, their density dependence and connections to Landau Fermi liquid theory are outlined. Finally, the density and temperature dependences of the chiral (quark) condensate are investigated.

  17. Chiral non-Fermi liquids

    Science.gov (United States)

    Sur, Shouvik; Lee, Sung-Sik

    2014-07-01

    A non-Fermi liquid state without time-reversal and parity symmetries arises when a chiral Fermi surface is coupled with a soft collective mode in two space dimensions. The full Fermi surface is described by a direct sum of chiral patch theories, which are decoupled from each other in the low-energy limit. Each patch includes low-energy excitations near a set of points on the Fermi surface with a common tangent vector. General patch theories are classified by the local shape of the Fermi surface, the dispersion of the critical boson, and the symmetry group, which form the data for distinct universality classes. We prove that a large class of chiral non-Fermi liquid states exists as stable critical states of matter. For this, we use a renormalization group scheme where low-energy excitations of the Fermi surface are interpreted as a collection of (1+1)-dimensional chiral fermions with a continuous flavor labeling the momentum along the Fermi surface. Due to chirality, the Wilsonian effective action is strictly UV finite. This allows one to extract the exact scaling exponents although the theories flow to strongly interacting field theories at low energies. In general, the low-energy effective theory of the full Fermi surface includes patch theories of more than one universality classes. As a result, physical responses include multiple universal components at low temperatures. We also point out that, in quantum field theories with extended Fermi surface, a noncommutative structure naturally emerges between a coordinate and a momentum which are orthogonal to each other. We show that the invalidity of patch description for Fermi liquid states is tied with the presence of UV/IR mixing associated with the emergent noncommutativity. On the other hand, UV/IR mixing is suppressed in non-Fermi liquid states due to UV insensitivity, and the patch description is valid.

  18. Molecular chirality and chiral capsule-type dimer formation of cyclic triamides via hydrogen-bonding interactions.

    Science.gov (United States)

    Fujimoto, Noriko; Matsumura, Mio; Azumaya, Isao; Nishiyama, Shizuka; Masu, Hyuma; Kagechika, Hiroyuki; Tanatani, Aya

    2012-05-18

    Chiral properties of bowl-shaped cyclic triamides bearing functional groups with hydrogen-bonding ability were examined. Chiral induction of cyclic triamide 3a was observed by addition of chiral amine in solution, and chiral separation was achieved by simple crystallization to afford chiral capsule-type dimer structure of 4a.

  19. Chiral extraction of ketoprofen enantiomers with chiral selector tartaric esters

    Institute of Scientific and Technical Information of China (English)

    ZHOU Dan; LIU Jia-jia; TANG Ke-wen; HUANG Ke-long

    2007-01-01

    Distribution behavior of ketoprofen enantiomers was examined in methanol aqueous and organic solvent mixture containing tartaric esters. The influence of length of alkyl chain of tartaric esters, concentration of L-tartaric esters and methanol aqueous, kind of organic solvent on partition ratio and separation factors was investigated. The results show that L-tartaric and D-tartaric esters have different chiral recognition abilities. S-ketoprofen is easily extracted by L-tartaric esters, and R-ketoprofen is easily extracted by D-tartaric esters. L-tartaric esters form more stable diastereomeric complexes with S-enantiomer than that with R-enantiomer. This distribution behavior is consistent with chiral recognition mechanism. With the increase of the concentration of tartaric ester from 0 to 0.3 mol/L, partition coefficient K and separation factor α increase. Also, the kind of organic solvent and the concentration of the methanol aqueous have significant influence on K and α.

  20. Spectral study of a chiral limit without chiral condensate

    CERN Document Server

    Bietenholz, Wolfgang

    2009-01-01

    Random Matrix Theory (RMT) has elaborated successful predictions for Dirac spectra in field theoretical models. However, a generic assumption by RMT has been a non-vanishing chiral condensate $\\Sigma$ in the chiral limit. Here we consider the 2-flavour Schwinger model, where this assumption does not hold. We simulated this model with dynamical overlap hypercube fermions, and entered terra incognita by analysing this Dirac spectrum. The usual RMT prediction for the unfolded level spacing distribution in a unitary ensemble is precisely confirmed. The microscopic spectrum does not perform a Banks-Casher plateau. Instead the obvious expectation is a density of the lowest eigenvalue $\\lambda_{1}$ which increases $\\propto \\lambda_{1}^{1/3}$. That would correspond to a scale-invariant parameter $\\propto \\lambda V^{3/4}$, which is, however, incompatible with our data. Instead we observe to high precision a scale-invariant parameter $z \\propto \\lambda V^{5/8}$. This surprising result implies a microscopic spectral den...

  1. Chiral Lagrangian and chiral quark model from confinement in QCD

    CERN Document Server

    Simonov, Yu A

    2015-01-01

    The effective chiral Lagrangian in both nonlocal form $L_{ECCL}$ and standard local form $L_{ECL}$ are derived in QCD using the confining kernel, obtained in the vacuum correlator formalism. As a result all coefficients of $L_{ECL}$ can be computed via $q\\bar q$ Green's functions. In the $p^2$ order of $L_{ECL}$ one obtains GOR relations and quark decay constants $f_a$ are calculated $a=1,...8$, while in the $p^4$ order the coefficients $L_1, L_2, L_3,L_4, L_5, L_6$ are obtained in good agreement with the values given by data. The chiral quark model is shown to be a simple consequence of $L_{ECCL}$ with defined coefficients. It is demonstrated that $L_{ECCL}$ gives an extension of the limiting low-energy Lagrangian $L_{ECL}$ to arbitrary momenta.

  2. Chiral heat wave and mixing of magnetic, vortical and heat waves in chiral media

    Energy Technology Data Exchange (ETDEWEB)

    Chernodub, M.N. [CNRS, Laboratoire de Mathématiques et Physique Théorique,Université de Tours, 37200 (France); Soft Matter Physics Laboratory, Far Eastern Federal University,Sukhanova 8, Vladivostok (Russian Federation); Department of Physics and Astronomy, University of Gent,Krijgslaan 281, S9, Gent (Belgium)

    2016-01-18

    We show that a hot rotating fluid of relativistic chiral fermions possesses a new gapless collective mode associated with coherent propagation of energy density and chiral density waves along the axis of rotation. This mode, which we call the Chiral Heat Wave, emerges due to a mixed gauge-gravitational anomaly. At finite density the Chiral Heat Wave couples to the Chiral Vortical Wave while in the presence of an external magnetic field it mixes with the Chiral Magnetic Wave. The coupling of the Chiral Magnetic and Chiral Vortical Waves is also demonstrated. We find that the coupled waves — which are coherent fluctuations of the vector, axial and energy currents — have generally different velocities compared to the velocities of the individual waves.

  3. Mechanism of chirality conversion by periodic change of temperature: Role of chiral clusters

    Science.gov (United States)

    Katsuno, Hiroyasu; Uwaha, Makio

    2016-01-01

    By grinding crystals in a solution, the chirality of crystal structure (and the molecular chirality for the case of chiral molecules as well) can be converted, and the cause of the phenomenon is attributed to crystal growth with chiral clusters. We show that the recently found chirality conversion with a periodic change of temperature can also be explained by crystal growth with chiral clusters. With the use of a generalized Becker-Döring model, which includes enantio-selective incorporation of small chiral clusters to large solid clusters, the change of cluster distribution and the mass flow between clusters are studied. The chiral clusters act as a reservoir to pump out the minority species to the majority, and the exponential amplification of the enantiomeric excess found in the experiment is reproduced in the numerical calculation.

  4. Focusing, Power Tunneling and Rejection from Chiral and/or Chiral Nihility/Nihility Metamaterials Layers

    CERN Document Server

    Shah, Syed Touseef Hussain; Syed, Aqeel A; Naqvi, Qaisar Abbas

    2013-01-01

    Focusing of electromagnetic plane wave from a large size paraboloidal reflector, composed of layers of chiral and/or chiral nihility metamaterials, has been studied us- ing Maslov's method. First, the transmission and reflection of electromagnetic plane wave from two parallel layers of chiral and/or chiral nihility metamaterials are cal- culated using transfer matrix method. The effects of change of angle of incidence, chirality parameters and impedances of layers are noted and discussed. Special cases by taking very large and small values of permittivity of second layer, while assuming value of corresponding chirality equal to zero, are also treated. These special cases are equivalent to reflection from a perfect electric conductor backed chiral layer and nihility backed chiral layer, respectively. Results of reflection from parallel layers have been utilized to study focusing from a large size paraboloidal reflector. The present study, on focusing from a paraboloidal re{\\deg}ector, not only unifies several ...

  5. Chiral nanoparticles in singular light fields

    Science.gov (United States)

    Vovk, Ilia A.; Baimuratov, Anvar S.; Zhu, Weiren; Shalkovskiy, Alexey G.; Baranov, Alexander V.; Fedorov, Anatoly V.; Rukhlenko, Ivan D.

    2017-04-01

    The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre-Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 109 times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams.

  6. Symmetries of Ginsparg-Wilson Chiral Fermions

    CERN Document Server

    Mandula, Jeffrey E

    2009-01-01

    The group structure of the variant chiral symmetry discovered by Luscher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of this extended chiral group, and the CP transformation properties of the symmetry generators are found. The group has an infinite-parameter subgroup, and the factor group whose elements are its cosets is isomorphic to the continuum chiral symmetry group. Features of the currents associated with these symmetries are discussed, including the fact that some different, non-commuting symmetry generators lead to the same Noether current. These are universal features of lattice chiral fermions based on the Ginsparg-Wilson relation; they occur in the overlap, domain-wall, and perfect-action formulations. In a solvable example - free overlap fermions - these non-canonical elements of lattice chiral symmetry are...

  7. Enantioselective recognition at mesoporous chiral metal surfaces

    Science.gov (United States)

    Wattanakit, Chularat; Côme, Yémima Bon Saint; Lapeyre, Veronique; Bopp, Philippe A.; Heim, Matthias; Yadnum, Sudarat; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander

    2014-02-01

    Chirality is widespread in natural systems, and artificial reproduction of chiral recognition is a major scientific challenge, especially owing to various potential applications ranging from catalysis to sensing and separation science. In this context, molecular imprinting is a well-known approach for generating materials with enantioselective properties, and it has been successfully employed using polymers. However, it is particularly difficult to synthesize chiral metal matrices by this method. Here we report the fabrication of a chirally imprinted mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and chiral template molecules. The porous platinum retains a chiral character after removal of the template molecules. A matrix obtained in this way exhibits a large active surface area due to its mesoporosity, and also shows a significant discrimination between two enantiomers, when they are probed using such materials as electrodes.

  8. Molecular chirality: language, history, and significance.

    Science.gov (United States)

    Gal, Joseph

    2013-01-01

    In this chapter some background material concerning molecular chirality and enantiomerism is presented. First some basic chemical-molecular aspects of chirality are reviewed, after which certain relevant terminology whose use in the literature has been problematic is discussed. Then an overview is provided of some of the early discoveries that laid the foundations of the science of molecular chirality in chemistry and biology, including the discovery of the phenomenon of molecular chirality by L. Pasteur, the proposals for the asymmetric carbon atom by J.H. van 't Hoff and J.A. Lebel, Pasteur's discovery of biological enantioselectivity, the discovery of enantioselectivity at biological receptors by A. Piutti, the studies of enzymatic stereoselectivity by E. Fischer, and the work on enantioselectivity in pharmacology by A. Cushny. Finally, the role of molecular chirality in pharmacotherapy and new-drug development, arguably one of the main driving forces for the current intense interest in the phenomenon of molecular chirality, is discussed.

  9. Spatial control of chirality in supramolecular aggregates

    Science.gov (United States)

    Castriciano, Maria A.; Gentili, Denis; Romeo, Andrea; Cavallini, Massimiliano; Scolaro, Luigi Monsù

    2017-01-01

    Chirality is one of the most intriguing properties of matter related to a molecule’s lack of mirror symmetry. The transmission of chirality from the molecular level up to the macroscopic scale has major implications in life sciences but it is also relevant for many chemical applications ranging from catalysis to spintronic. These technological applications require an accurate control of morphology, homogeneity and chiral handedness of thin films and nanostructures. We demonstrate a simple approach to specifically transfer chirality to the model supramolecular system of J aggregates of the protonated form of tetrakis(4-sulfonatophenyl)-porphyrin by utilizing a soft lithography technique. This approach successfully allows the fabrication of an ordered distribution of sub-micrometric structures in precise and controllable positions with programmed chirality, providing a fundamental breakthrough toward the exploitation of chiral supramolecular aggregates in technological applications, such as sensors, non-linear optics and spintronic. PMID:28275239

  10. Spatial control of chirality in supramolecular aggregates.

    Science.gov (United States)

    Castriciano, Maria A; Gentili, Denis; Romeo, Andrea; Cavallini, Massimiliano; Scolaro, Luigi Monsù

    2017-03-09

    Chirality is one of the most intriguing properties of matter related to a molecule's lack of mirror symmetry. The transmission of chirality from the molecular level up to the macroscopic scale has major implications in life sciences but it is also relevant for many chemical applications ranging from catalysis to spintronic. These technological applications require an accurate control of morphology, homogeneity and chiral handedness of thin films and nanostructures. We demonstrate a simple approach to specifically transfer chirality to the model supramolecular system of J aggregates of the protonated form of tetrakis(4-sulfonatophenyl)-porphyrin by utilizing a soft lithography technique. This approach successfully allows the fabrication of an ordered distribution of sub-micrometric structures in precise and controllable positions with programmed chirality, providing a fundamental breakthrough toward the exploitation of chiral supramolecular aggregates in technological applications, such as sensors, non-linear optics and spintronic.

  11. Asymmetric synthesis using chiral-encoded metal

    Science.gov (United States)

    Yutthalekha, Thittaya; Wattanakit, Chularat; Lapeyre, Veronique; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander

    2016-08-01

    The synthesis of chiral compounds is of crucial importance in many areas of society and science, including medicine, biology, chemistry, biotechnology and agriculture. Thus, there is a fundamental interest in developing new approaches for the selective production of enantiomers. Here we report the use of mesoporous metal structures with encoded geometric chiral information for inducing asymmetry in the electrochemical synthesis of mandelic acid as a model molecule. The chiral-encoded mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and the chiral template molecule, perfectly retains the chiral information after removal of the template. Starting from a prochiral compound we demonstrate enantiomeric excess of the (R)-enantiomer when using (R)-imprinted electrodes and vice versa for the (S)-imprinted ones. Moreover, changing the amount of chiral cavities in the material allows tuning the enantioselectivity.

  12. ENANTIOMERIC RATIOS OF CHIRAL PCB ATROPISOMERS IN RADIODATED SEDIMENT CORES

    Science.gov (United States)

    Enantiomeric ratios (ERs)) of chiral polychlorinated biphenyl (PCB) atropisomers were quantified in radiodated sediment cores of Lake Hartwell SC, a reservoir heavily impacted by PCBS, to study spatial and temporal changes in chirality. A chiral analysis of cores showed accumulat...

  13. Objects of maximum electromagnetic chirality

    CERN Document Server

    Fernandez-Corbaton, Ivan

    2015-01-01

    We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. The upper bound is attained if and only if the object is transparent for fields of one handedness (helicity). Additionally, electromagnetic duality symmetry, i.e. helicity preservation upon scattering, turns out to be a necessary condition for reciprocal scatterers to attain the upper bound. We use these results to provide requirements for the design of such extremal scatterers. The requirements can be formulated as constraints on the polarizability tensors for dipolar scatterers or as material constitutive relations. We also outline two applications for objects of maximum electromagnetic chirality: A twofold resonantly enhanced and background free circular dichroism measurement setup, and angle independent helicity filtering glasses.

  14. Negative refractive index in chiral metamaterials.

    Science.gov (United States)

    Zhang, Shuang; Park, Yong-Shik; Li, Jensen; Lu, Xinchao; Zhang, Weili; Zhang, Xiang

    2009-01-16

    We experimentally demonstrate a chiral metamaterial exhibiting negative refractive index at terahertz frequencies. The presence of strong chirality in the terahertz metamaterial lifts the degeneracy for the two circularly polarized waves and allows for the achievement of negative refractive index without requiring simultaneously negative permittivity and negative permeability. The realization of terahertz chiral negative index metamaterials offers opportunities for investigation of their novel electromagnetic properties, such as negative refraction and negative reflection, as well as important terahertz device applications.

  15. Enantioselective Biotransformation of Chiral Persistent Organic Pollutants.

    Science.gov (United States)

    Zhang, Ying; Ye, Jing; Liu, Min

    2017-01-01

    Enantiomers of chiral compounds commonly undergo enantioselective transformation in most biologically mediated processes. As chiral persistent organic pollutants (POPs) are extensively distributed in the environment, differences between enantiomers in biotransformation should be carefully considered to obtain exact enrichment and specific health risks. This review provides an overview of in vivo biotransformation of chiral POPs currently indicated in the Stockholm Convention and their chiral metabolites. Peer-reviewed journal articles focused on the research question were thoroughly searched. A set of inclusion and exclusion criteria were developed to identify relevant studies. We mainly compared the results from different animal models under controlled laboratory conditions to show the difference between enantiomers in terms of distinct transformation potential. Interactions with enzymes involved in enantioselective biotransformation, especially cytochrome P450 (CYP), were discussed. Further research areas regarding this issue were proposed. Limited evidence for a few POPs has been found in 30 studies. Enantioselective biotransformation of α-hexachlorocyclohexane (α-HCH), chlordane, dichlorodiphenyltrichloroethane (DDT), heptachlor, hexabromocyclododecane (HBCD), polychlorinated biphenyls (PCBs), and toxaphene, has been investigated using laboratory mammal, fish, bird, and worm models. Tissue and excreta distributions, as well as bioaccumulation and elimination kinetics after administration of racemate and pure enantiomers, have been analyzed in these studies. Changes in enantiomeric fractions have been considered as an indicator of enantioselective biotransformation of chiral POPs in most studies. Results of different laboratory animal models revealed that chiral POP biotransformation is seriously affected by chirality. Pronounced results of species-, tissue-, gender-, and individual-dependent differences are observed in in vivo biotransformation of chiral POPs

  16. Constructions of Chiral Polytopes of Small Rank

    CERN Document Server

    D'Azevedo, Antonio Breda; Schulte, Egon

    2010-01-01

    An abstract polytope of rank n is said to be chiral if its automorphism group has precisely two orbits on the flags, such that adjacent flags belong to distinct orbits. The present paper describes a general method for deriving new finite chiral polytopes from old finite chiral polytopes of the same rank. In particular, the technique is used to construct many new examples in ranks 3, 4 and 5.

  17. A spectral route to determining chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We show how one-dimensional structured media can be used to measure chirality, via the spectral shift of the photonic band gap edges. Analytically, we show that a chiral contrast can, in some cases, be mapped unto an index contrast, thereby greatly simplifying the analysis of such structures. Using...... this mapping, we derive a first-order shift of the band gap edges with chirality. Potentially, this effect could be used for measuring enantiomeric excess....

  18. Infinite Chiral Symmetry in Four Dimensions

    CERN Document Server

    Beem, Christopher; Liendo, Pedro; Peelaers, Wolfger; Rastelli, Leonardo; van Rees, Balt C

    2015-01-01

    We describe a new correspondence between four-dimensional conformal field theories with extended supersymmetry and two-dimensional chiral algebras. The meromorphic correlators of the chiral algebra compute correlators in a protected sector of the four-dimensional theory. Infinite chiral symmetry has far-reaching consequences for the spectral data, correlation functions, and central charges of any four-dimensional theory with ${\\mathcal N}=2$ superconformal symmetry.

  19. Chiral near fields generated from plasmonic lattices

    CERN Document Server

    Canaguier-Durand, Antoine

    2014-01-01

    Plasmonic fields are usually considered non-chiral because of the transverse magnetic polarization of surface plasmon modes. We however show here that plasmonic lattices built from coherent superpositions of surface plasmons can generate optical chirality in the interfering near field. We reveal in particular the emergence of plasmonic potentials relevant to the generation of near-field chiral forces. This draws promising perspectives for performing enantiomeric separation schemes within the near field.

  20. Chiral Plasmonic Nanostructures on Achiral Nanopillars

    Science.gov (United States)

    2013-10-10

    0704-0188 3. DATES COVERED (From - To) - UU UU UU UU Approved for public release; distribution is unlimited. Chiral Plasmonic Nanostructures on Achiral...Nanopillars Chirality of plasmonic films can be strongly enhanced by threedimensional (3D) out-of-plane geometries. The complexity of lithographic...methods currently used to produce such structures and other methods utilizing chiral templates impose limitations on spectral windows of chiroptical

  1. Chirality and the angular momentum of light

    Science.gov (United States)

    Cameron, Robert P.; Götte, Jörg B.; Barnett, Stephen M.; Yao, Alison M.

    2017-02-01

    Chirality is exhibited by objects that cannot be rotated into their mirror images. It is far from obvious that this has anything to do with the angular momentum of light, which owes its existence to rotational symmetries. There is nevertheless a subtle connection between chirality and the angular momentum of light. We demonstrate this connection and, in particular, its significance in the context of chiral light-matter interactions. This article is part of the themed issue 'Optical orbital angular momentum'.

  2. Chiral phases of fundamental and adjoint quarks

    Energy Technology Data Exchange (ETDEWEB)

    Natale, A. A. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC 09210-170, Santo André, SP (Brazil); Instituto de Física Teórica - UNESP Rua Dr. Bento T. Ferraz, 271, Bl.II - 01140-070, São Paulo, SP (Brazil)

    2016-01-22

    We consider a QCD chiral symmetry breaking model where the gap equation contains an effective confining propagator and a dressed gluon propagator with a dynamically generated mass. This model is able to explain the ratios between the chiral transition and deconfinement temperatures in the case of fundamental and adjoint quarks. It also predicts the recovery of the chiral symmetry for a large number of quarks (n{sub f} ≈ 11 – 13) in agreement with lattice data.

  3. Chiral Separation of Erythromycin as a New Chiral Selector on CE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Erythromycin as a new chiral selector was first used for chrial separation of four derivatives of biphenyldimethylester enantiomers on CE. The influence of pH, the chiral selector concentration and organic modifiers were preliminarily studied. Experiments show that the erythromycin as chiral selector is useful to CE.

  4. Chiral Induction with Chiral Conformational Switches in the Limit of Low "Sergeants to Soldiers" Ratio

    DEFF Research Database (Denmark)

    Nuermaimaiti, Ajiguli; Bombis, Christian; Knudsen, Martin Markvard

    2014-01-01

    " mechanism for an oligo(phenylene ethynylene) based chiral conformational switch by coadsorbing it with an intrinsically chiral seed on Au(111). Through statistical analysis of scanning tunneling microscopy (STM) data we demonstrate successful chiral induction with a very low concentration of seeding...

  5. Staggered chiral random matrix theory

    CERN Document Server

    Osborn, James C

    2010-01-01

    We present a random matrix theory (RMT) for the staggered lattice QCD Dirac operator. The staggered RMT is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.

  6. Chiral methyl-branched pheromones.

    Science.gov (United States)

    Ando, Tetsu; Yamakawa, Rei

    2015-07-01

    Insect pheromones are some of the most interesting natural products because they are utilized for interspecific communication between various insects, such as beetles, moths, ants, and cockroaches. A large number of compounds of many kinds have been identified as pheromone components, reflecting the diversity of insect species. While this review deals only with chiral methyl-branched pheromones, the chemical structures of more than one hundred non-terpene compounds have been determined by applying excellent analytical techniques. Furthermore, their stereoselective syntheses have been achieved by employing trustworthy chiral sources and ingenious enantioselective reactions. The information has been reviewed here not only to make them available for new research but also to understand the characteristic chemical structures of the chiral pheromones. Since biosynthetic studies are still limited, it might be meaningful to examine whether the structures, particularly the positions and configurations of the branched methyl groups, are correlated with the taxonomy of the pheromone producers and also with the function of the pheromones in communication systems.

  7. Chiral symmetry breaking and monopoles

    CERN Document Server

    Di Giacomo, Adriano; Pucci, Fabrizio

    2015-01-01

    To understand the relation between the chiral symmetry breaking and monopoles, the chiral condensate which is the order parameter of the chiral symmetry breaking is calculated in the $\\overline{\\mbox{MS}}$ scheme at 2 [GeV]. First, we add one pair of monopoles, varying the monopole charges $m_{c}$ from zero to four, to SU(3) quenched configurations by a monopole creation operator. The low-lying eigenvalues of the Overlap Dirac operator are computed from the gauge links of the normal configurations and the configurations with additional monopoles. Next, we compare the distributions of the nearest-neighbor spacing of the low-lying eigenvalues with the prediction of the random matrix theory. The low-lying eigenvalues not depending on the scale parameter $\\Sigma$ are compared to the prediction of the random matrix theory. The results show the consistency with the random matrix theory. Thus, the additional monopoles do not affect the low-lying eigenvalues. Moreover, we discover that the additional monopoles increa...

  8. Effects from inhomogeneities in the chiral transition

    CERN Document Server

    Taketani, B G; Taketani, Bruno G.; Fraga, Eduardo S.

    2006-01-01

    We consider an approximation procedure to evaluate the finite-temperature one-loop fermionic density in the presence of a chiral background field which systematically incorporates effects from inhomogeneities in the chiral field through a derivative expansion. We apply the method to the case of a simple low-energy effective chiral model which is commonly used in the study of the chiral phase transition, the linear sigma-model coupled to quarks. The modifications in the effective potential and their consequences for the bubble nucleation process are discussed.

  9. Supramolecular Chirality in Dynamic Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Hiroyuki Miyake

    2014-10-01

    Full Text Available Labile metal complexes have a useful coordination bond; which is weaker than a covalent C–C bond and is reversibly and dynamically formed and dissociated. Such labile metal complexes also can be used to construct chiral shapes and offer dynamic conversion of chiral molecular shapes in response to external stimuli. This review provides recent examples of chirality induction and describes the dynamic conversion systems produced by chiral metal complexes including labile metal centers, most of which respond to external stimuli by exhibiting sophisticated conversion phenomena.

  10. Laser Writing of Multiscale Chiral Polymer Metamaterials

    Directory of Open Access Journals (Sweden)

    E. P. Furlani

    2012-01-01

    Full Text Available A new approach to metamaterials is presented that involves laser-based patterning of novel chiral polymer media, wherein chirality is realized at two distinct length scales, intrinsically at the molecular level and geometrically at a length scale on the order of the wavelength of the incident field. In this approach, femtosecond-pulsed laser-induced two-photon lithography (TPL is used to pattern a photoresist-chiral polymer mixture into planar chiral shapes. Enhanced bulk chirality can be realized by tuning the wavelength-dependent chiral response at both the molecular and geometric level to ensure an overlap of their respective spectra. The approach is demonstrated via the fabrication of a metamaterial consisting of a two-dimensional array of chiral polymer-based L-structures. The fabrication process is described and modeling is performed to demonstrate the distinction between molecular and planar geometric-based chirality and the effects of the enhanced multiscale chirality on the optical response of such media. This new approach to metamaterials holds promise for the development of tunable, polymer-based optical metamaterials with low loss.

  11. Plasmonic lateral forces on chiral spheres

    CERN Document Server

    Canaguier-Durand, Antoine

    2015-01-01

    We show that the optical force exerted on a finite size chiral sphere by a surface plasmon mode has a component along a direction perpendicular to the plasmon linear momentum. We reveal how this chiral lateral force, pointing in opposite directions for opposite enantiomers, stems from an angular-to-linear crossed momentum transfer involving the plasmon transverse spin angular momentum density and mediated by the chirality of the sphere. Our multipolar approach allows us discussing the inclusion of the recoil term in the force on a small sphere taken in the dipolar limit and observing sign inversions of the lateral chiral force when the size of the sphere increases.

  12. On the gauging of chiral bosons

    CERN Document Server

    Wotzasek, C

    1995-01-01

    We study the coupling of chiral bosons to external electromagnetic fields. It is observed that a naive gauging procedure leaves the gauge invariant chirality condition incompatible with the field equations. We propose the use of this feature as a consistency test to select the appropriate way to perform the gauge coupling. We verify that among all the possible gauging schemes, only the coupling of gauge fields with chiral currents passes the consistency test. As an application, we use this gauging scheme to show how the introduction of a gauge field becomes necessary in order to sold together a right and a left chiral boson.

  13. Synthesis and Chiral Recognition of a New Type of Chiral Calix[4]arene Derivatives

    Institute of Scientific and Technical Information of China (English)

    HE,Yong-Bing; LI,Jian-Feng; XIAO,Yuan-Jing; WEI,Lan-Hua; WU,Xiao-Jun; MENG,Ling-Zhi

    2003-01-01

    Two new chiral calix[4] arenes bearing chiral pendants, which were from by-product of the antibiotic industry, were synthesized and characterized by 1H NMR, MS-FAB and elemental analysis. Studies of 1H NMR of the two calix [4] arene derivatives indicate that they exist in cone conformation in solution. Results of chiral recognition of the two chiral ligands 2a and 2b towards the tartaric acid derivative 3 show that ligand 2a exhibited good chiral recognition abilities compared to ligand 2b.

  14. Chiral memory via chiral amplification and selective depolymerization of porphyrin aggregates.

    Science.gov (United States)

    Helmich, Floris; Lee, Cameron C; Schenning, Albertus P H J; Meijer, E W

    2010-12-01

    Chiral memory at the supramolecular level is obtained via a new approach using chiral Zn porphrins and achiral Cu porphyrins. In a "sergeant-and-soldiers" experiment, the Zn "sergeant" transfers its own chirality to Cu "soldiers" and, after chiral amplification, the "sergeant" is removed from the coaggregates by axial ligation with a Lewis base. After this extraction, the preferred helicity observed for the aggregates containing achiral Cu porphyrins reveals a chiral memory effect that is stable and can be erased and partially restored upon subsequent heating and cooling.

  15. The Optical Chirality Flux as a Useful Far-Field Probe of Chiral Near Fields

    CERN Document Server

    Poulikakos, Lisa V; McPeak, Kevin M; Burger, Sven; Niegemann, Jens; Hafner, Christian; Norris, David J

    2016-01-01

    To optimize the interaction between chiral matter and highly twisted light, quantities that can help characterize chiral electromagnetic fields near nanostructures are needed. Here, by analogy with Poynting's theorem, we formulate the time-averaged conservation law of optical chirality in lossy dispersive media and identify the optical chirality flux as an ideal far-field observable for characterizing chiral optical near fields. Bounded by the conservation law, we show that it provides precise information, unavailable from circular dichroism spectroscopy, on the magnitude and handedness of highly twisted fields near nanostructures.

  16. Cofactor-Controlled Chirality of Tropoisomeric Ligand

    NARCIS (Netherlands)

    Théveau, L.; Bellini, R.; Dydio, P.; Szabo, Z.; van der Werf, A.; Sander, R.A.; Reek, J.N.H.; Moberg, C.

    2016-01-01

    A new tropos ligand with an integrated anion receptor receptor site has been prepared. Chiral carboxylate and phosphate anions that bind in the anion receptor unit proved capable of stabilizing chiral conformations of the achiral flexible bidentate biaryl phosphite ligand, as shown by variable

  17. Chiral magnetic effect in condensed matter systems

    Science.gov (United States)

    Li, Qiang; Kharzeev, Dmitri E.

    2016-12-01

    The chiral magnetic effect (CME) is the generation of electrical current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum chiral anomaly [S. L. Adler. Axial-vector vertex in spinor electrodynamics. Physical Review, 177, 2426 (1969), J. S. Bell and R. Jackiw. A PCAC puzzle: π 0 γγin the σ-model. Il Nuovo Cimento A, 60, 47-61 (1969)] in systems possessing charged chiral fermions. In quark-gluon plasma containing nearly massless quarks, the chirality imbalance is sourced by the topological transitions. In condensed matter systems, the chiral quasiparticles emerge in gapless semiconductors with two energy bands having pointlike degeneracies opening the path to the study of chiral anomaly [H. B. Nielsen and M. Ninomiya. The Adler-Bell-Jackiw anomaly and Weyl fermions in a crystal. Physics Letters B, 130, 389-396 (1983)]. Recently, these novel materials - so-called Dirac and Weyl semimetals have been discovered experimentally, are suitable for the investigation of the CME in condensed matter experiments. Here we report on the first experimental observation of the CME in a 3D Dirac semimetal ZrTe5 [Q. Li, D. E. Kharzeev, C. Zhang, Y. Huang, I. Pletikosić, A. V. Fedorov, R. D. Zhong, J. A. Schneeloch, G. D. Gu, and T. Valla. Chiral magnetic effect in ZrTe5. Nature Physics (2016) doi:10.1038/nphys3648].

  18. A NEW CHIRAL ALLOTROPE C80

    Institute of Scientific and Technical Information of China (English)

    詹克明

    1994-01-01

    The theoretical prophecy is given on a new chiral allotrope of Fullerene-C80.C80 molecuule should have 3C2 symmetric axes,which should be vertical each othyer.C80 should have two chiral allotropes,13C-NMR spectra of C80 should consist of 20 lines of equal intensity.

  19. Quenched chiral perturbation theory to one loop

    NARCIS (Netherlands)

    Colangelo, Gilberto; Pallante, Elisabetta

    1998-01-01

    We calculate the divergences of the generating functional of quenched chiral perturbation theory at one loop, and renormalize the theory by an appropriate definition of the counterterms. We show that the quenched chiral logarithms can be accounted for by defining a renormalized B0 parameter which, a

  20. Orientation-Dependent Handedness and Chiral Design

    Directory of Open Access Journals (Sweden)

    Efi Efrati

    2014-01-01

    Full Text Available Chirality occupies a central role in fields ranging from biological self-assembly to the design of optical metamaterials. The definition of chirality, as given by Lord Kelvin, associates chirality with the lack of mirror symmetry: the inability to superpose an object on its mirror image. While this definition has guided the classification of chiral objects for over a century, the quantification of handed phenomena based on this definition has proven elusive, if not impossible, as manifest in the paradox of chiral connectedness. In this work, we put forward a quantification scheme in which the handedness of an object depends on the direction in which it is viewed. While consistent with familiar chiral notions, such as the right-hand rule, this framework allows objects to be simultaneously right and left handed. We demonstrate this orientation dependence in three different systems—a biomimetic elastic bilayer, a chiral propeller, and optical metamaterial—and find quantitative agreement with chirality pseudotensors whose form we explicitly compute. The use of this approach resolves the existing paradoxes and naturally enables the design of handed metamaterials from symmetry principles.

  1. Monitoring molecular chirality exchange by photon echoes

    Directory of Open Access Journals (Sweden)

    Mukamel Shaul

    2013-03-01

    Full Text Available We construct pulse polarization configurations in heterodyne four wave mixing for monitoring ultrafast(picosecondexchange rates between optical isomers with axial chirality.This information is not available from linear circular dichroism,since enantiomers may not be isolated and racemate shows no chiral signal.

  2. Chiral metamaterials reduce the attractive Casimir force

    Science.gov (United States)

    Zhao, R.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.

    2010-08-01

    In our previous work [R. Zhao, J. Zhou, Th. Koschny, E. N. Economou, and C. M. Soukoulis, Phys. Rev. Lett. 103, 103602 (2009)], we demonstrated theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials if the chirality is strong enough. In our recent work [R. Zhao, Th. Koschny, E.N. Economou, and C.M. Soukoulis, Phys. Rev. B 81, 235126 (2010)], we checked some chiral metamaterial designs and found that the artificial chiral metamaterials constructed by passive materials is very difficult to reach the critical chirality to realize repulsive Casimir force. Therefore, in this paper, we give a four-folded rotated Ω-particle chiral metamaterial as an example, use the effective medium approximation to retrieval the constitutive parameters, and take the same procedure as we did before to see how much the chiral metamaterial can reduce the attractive force. It shows that this un-optimized chiral metamaterial can reduce the Casimir attraction by 70%.

  3. LINEARLY POLARIZED PROBES OF SURFACE CHIRALITY

    NARCIS (Netherlands)

    VERBIEST, T; KAURANEN, M; MAKI, JJ; TEERENSTRA, MN; SCHOUTEN, AJ; NOLTE, RJM; PERSOONS, A

    1995-01-01

    We present a new nonlinear optical technique to study surface chirality. We demonstrate experimentally that the efficiency of second-harmonic generation from isotropic chiral surfaces is different for excitation with fundamental light that is +45 degrees and -45 degrees linearly polarized with respe

  4. DEVELOPMENT AND REGISTRATION OF CHIRAL DRUGS

    NARCIS (Netherlands)

    WITTE, DT; ENSING, K; FRANKE, JP; DEZEEUW, RA

    1993-01-01

    In this review we describe the impact of chirality on drug development and registration in the United States, Japan and the European Community. Enantiomers may have differences in their pharmacological profiles, and, therefore, chiral drugs ask for special analytical and pharmacological attention du

  5. LINEARLY POLARIZED PROBES OF SURFACE CHIRALITY

    NARCIS (Netherlands)

    VERBIEST, T; KAURANEN, M; MAKI, JJ; TEERENSTRA, MN; SCHOUTEN, AJ; NOLTE, RJM; PERSOONS, A

    1995-01-01

    We present a new nonlinear optical technique to study surface chirality. We demonstrate experimentally that the efficiency of second-harmonic generation from isotropic chiral surfaces is different for excitation with fundamental light that is +45 degrees and -45 degrees linearly polarized with respe

  6. An Extended Chiral SU(3) Quark Model

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zong-Ye; YU You-Wen; WANG Ping; DAI Lian-Rong

    2003-01-01

    The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiralfields are considered, the phase shifts of 1 So wave are obviously improved.

  7. Chiral THz metamaterial with tunable optical activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jiangfeng [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; O' Hara, John [Los Alamos National Laboratory; Chowdhury, Roy [Los Alamos National Laboratory; Zhao, Rongkuo [IOWA STATE UNIV; Soukoullis, Costas M [IOWA STATE UNIV

    2010-01-01

    Optical activity in chiral metamaterials is demonstrated in simulation and shows actively tunable giant polarization rotation at THz frequencies. Electric current distributions show that pure chirality is achieved by our bi-Iayer chiral metamaterial design. The chirality can be optically controlled by illumination with near-infrared light. Optical activity, occurring in chiral materials such as DNA, sugar and many other bio-molecules, is a phenomenon of great importance to many areas of science including molecular biology, analytical chemistry, optoelectronics and display applications. This phenomenon is well understood at an effective medium level as a magnetic/electric moment excited by the electric/magnetic field of the incident electromagnetic (EM) wave. Usually, natural chiral materials exhibit very weak optical activity e.g. a gyrotropic quartz crystal. The optical activity of chiral metamaterials, however, can be five orders of magnitude stronger. Chiral metamaterials are made of sub-wavelength resonators lacking symmetry planes. The asymmetry allows magnetic moments to be excited by the electric field of the incident EM wave and vice versa. Recently, chiral metamaterials have been demonstrated and lead to prospects in giant optical activity, circular dichroism, negative refraction and reversing the Casmir force. These fascinating optical properties require strong chirality, which may be designed through the microscopic structure of chiral metamaterials. However, these metamaterials have a fixed response function, defined by the geometric structuring, which limits their ability to manipulate EM waves. Active metamaterials realize dynamic control of response functions and have produced many influential applications such as ultra-fast switching devices, frequency and phase modulation and memory devices. Introducing active designs to chiral metamaterials will give additional freedom in controlling the optical activity, and therefore enable dynamic manipulation

  8. Large Chiroptical Effects in Planar Chiral Metamaterials

    Science.gov (United States)

    Ye, Weimin; Yuan, Xiaodong; Guo, Chucai; Zhang, Jianfa; Yang, Biao; Zhang, Shuang

    2017-05-01

    Chiroptical effects characterized by different optical responses for left- (LCP) and right-handed circularly polarized light (RCP) are powerful and valuable tools in optics with wide applications in polarization-resolved imaging and sensing. Previously observed strong chiroptical effects are limited to metamaterials with complex three-dimensional chiral structures at the subwavelength scale. Although asymmetrical transmission of LCP and RCP have been investigated in planar chiral metasurfaces, the observed weak chiroptical effects result from anisotropic Ohmic dissipation of the metal constituents. Here, we demonstrate by theory and proof-of-concept experiments that a large difference in transmittances of LCP and RCP can be attained in a single-layer planar chiral metamaterial with a subwavelength thickness. Without violating the reciprocity and mirror symmetry, the strong chiroptical effect, independent of dielectric loss, arises from a mechanism of multimode interference. The described effect may lead to a gateway towards chiral manipulations of light and chiral optical devices.

  9. Lambda Hypernuclei in a Chiral Hadronic Model

    Institute of Scientific and Technical Information of China (English)

    LIANG Yin-Hua; GUO Hua

    2005-01-01

    @@ Nuclear matter calculations in a chiral hadronic model have been performed. It has been found that the scalar and the vector potentials and binding energies per nucleon in the chiral hadronic model are very close to those of the microscopic relativistic Brueckner-Hartree-Fock calculations. The good results for finite nuclei can be obtained in the mean field approximation only if scalar mass ms and coupling constant gs have been improved with the fixed values of cs2 ≡ g2s(M/ms)2 as those given by the original parameter sets of the chiral hadronic model. Then the chiral hadronic model is extended to lambda hypernuclei. Our results predicted by the chiral hadronic model are compared with those by the nonlinear Walecka model. It has been shown that the hadronic model can also be used to describe lambda hypernuclei successfully.

  10. Microwave chirality discrimination in enantiomeric liquids

    Science.gov (United States)

    Hollander, E.; Kamenetskii, E. O.; Shavit, R.

    2017-07-01

    Chirality discrimination is of fundamental interest in biology, chemistry, and metamaterial studies. In optics, near-field plasmon-resonance spectroscopy with superchiral probing fields is effectively applicable for analyses of large biomolecules with chiral properties. We show possibility for microwave near-field chirality discrimination analysis based on magnon-resonance spectroscopy. Newly developed capabilities in microwave sensing using magnetoelectric (ME) probing fields originated from multiresonance magnetic-dipolar-mode oscillations in quasi-2D yttrium-iron-garnet disks provide potential for unprecedented measurements of chemical and biological objects. We report on microwave near-field chirality discrimination for aqueous D- and L-glucose solutions. The shown ME-field sensing is addressed to deepen our understanding of microwave-biosystem interactions. It can also be important for an analysis and design of microwave chiral metamaterials.

  11. Chiral Superfluidity for the Heavy Ion Collisions

    CERN Document Server

    Kalaydzhyan, T

    2013-01-01

    We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the "superfluid" component gives rise to the chiral magnetic, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model. By considering probe quarks one can show that the fermionic spectrum at the intermediate tempera...

  12. Cosmic chirality both true and false.

    Science.gov (United States)

    Barron, Laurence D

    2012-12-01

    The discrete symmetries of parity P, time reversal T, and charge conjugation C may be used to characterize the properties of chiral systems. It is well known that parity violation infiltrates into ordinary matter via an interaction between the nucleons and electrons, mediated by the Z(0) particle, that lifts the degeneracy of the mirror-image enantiomers of a chiral molecule. Being odd under P but even under T, this P-violating interaction exhibits true chirality and so may induce absolute enantioselection under all circumstances. It has been suggested that CP violation may also infiltrate into ordinary matter via a P-odd, T-odd interaction mediated by the (as yet undetected) axion. This CP-violating interaction exhibits false chirality and so may induce absolute enantioselection in processes far from equilibrium. Both true and false cosmic chirality should be considered together as possible sources of homochirality in the molecules of life.

  13. A liquid crystalline chirality balance for vapours

    Science.gov (United States)

    Ohzono, Takuya; Yamamoto, Takahiro; Fukuda, Jun-Ichi

    2014-04-01

    Chiral discrimination of vapours plays an important role in olfactory perception of biological systems and its realization by artificial sensors has been an intriguing challenge. Here, we report a simple method that tangibly visualizes the chirality of a diverse variety of molecules dissolved from vapours with high sensitivity, by making use of a structural change in a periodic microstructure of a nematic liquid crystal confined in open microchannels. This microstructure is accompanied by a topological line defect of a zigzag form with equal lengths of ‘zig’ and ‘zag.’ We find that a tiny amount of vapour of chiral molecules injected onto the liquid crystal induces the imbalance of ‘zig’ and ‘zag’ depending on its enantiomeric excess within a few seconds. Our liquid-crystal-based ‘chirality balance’ offers a simple, quick and versatile chirality-sensing/-screening method for gas-phase analysis (for example, for odours, environmental chemicals or drugs).

  14. Chirality on Surfaces: Modeling and Behaviour.

    Energy Technology Data Exchange (ETDEWEB)

    Paci, Irina; Szleifer, Igal; Ratner, Mark A.

    2007-09-01

    The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Chirality has been a fascinating topic in chemistry, ever since its first observation by Biot in 1815. Its molecular basis was first understood by Pasteur in 1848. Enantiomers, identical in every way but mirror-images of each other, have similar physical properties, behave identically in chemical reactions with achiral molecules, but have very different interactions with chiral molecules. In recent decades, chirality has become an important direction in pharmaceutical research, as many drugs have stereoselective activity. This review focuses on a new aspect of chiral resolution on solid surfaces, and relationships between molecular structure, thermodynamic effects, and the result of chiral surface self-organization.

  15. Radiation pressure of active dispersive chiral slabs.

    Science.gov (United States)

    Wang, Maoyan; Li, Hailong; Gao, Dongliang; Gao, Lei; Xu, Jun; Qiu, Cheng-Wei

    2015-06-29

    We report a mechanism to obtain optical pulling or pushing forces exerted on the active dispersive chiral media. Electromagnetic wave equations for the pure chiral media using constitutive relations containing dispersive Drude models are numerically solved by means of Auxiliary Differential Equation Finite Difference Time Domain (ADE-FDTD) method. This method allows us to access the time averaged Lorentz force densities exerted on the magnetoelectric coupling chiral slabs via the derivation of bound electric and magnetic charge densities, as well as bound electric and magnetic current densities. Due to the continuously coupled cross-polarized electromagnetic waves, we find that the pressure gradient force is engendered on the active chiral slabs under a plane wave incidence. By changing the material parameters of the slabs, the total radiation pressure exerted on a single slab can be directed either along the propagation direction or in the opposite direction. This finding provides a promising avenue for detecting the chirality of materials by optical forces.

  16. Chiral Anomaly in Contorted Spacetimes

    CERN Document Server

    Mielke, E W

    1999-01-01

    The Dirac equation in Riemann-Cartan spacetimes with torsion is reconsidered. As is well-known, only the axial covector torsion $A$, a one-form, couples to massive Dirac fields. Using diagrammatic techniques, we show that besides the familiar Riemannian term only the Pontrjagin type four-form $dA\\wedge dA$ does arise additionally in the chiral anomaly, but not the Nieh-Yan term $d ^* A$, as has been claimed recently. Implications for cosmic strings in Einstein-Cartan theory as well as for Ashtekar's canonical approach to quantum gravity are discussed.

  17. Status of chiral meson physics

    Energy Technology Data Exchange (ETDEWEB)

    Bijnens, Johan [Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, SE 22362 Lund (Sweden)

    2016-01-22

    This talk includes a short introduction to Chiral Perturbation Theory in the meson sector concentrating on a number of recent developments. I discuss the latest fit of the low-energy constants. Finite volume corrections are discussed for the case with twisted boundary conditions for form-factors and first results at two-loops for three flavours for masses. The last part discusses the extension to other symmetry breaking patterns relevant for technicolour and related theories as well as the calculation of leading logarithms to high loop orders.

  18. Principal chiral model on superspheres

    Energy Technology Data Exchange (ETDEWEB)

    Mitev, V.; Schomerus, V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Quella, T. [Amsterdam Univ. (Netherlands). Inst. for Theoretical Physics

    2008-09-15

    We investigate the spectrum of the principal chiral model (PCM) on odd-dimensional superspheres as a function of the curvature radius R. For volume-filling branes on S{sup 3} {sup vertical} {sup stroke} {sup 2}, we compute the exact boundary spectrum as a function of R. The extension to higher dimensional superspheres is discussed, but not carried out in detail. Our results provide very convincing evidence in favor of the strong-weak coupling duality between supersphere PCMs and OSP(2S+2 vertical stroke 2S) Gross-Neveu models that was recently conjectured by Candu and Saleur. (orig.)

  19. Synthesis and characterization of mixed ligand chiral nanoclusters

    KAUST Repository

    Guven, Zekiye P.

    2016-06-22

    Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

  20. Chirality controlled responsive self-assembled nanotubes in water

    NARCIS (Netherlands)

    van Dijken, D. J.; Stacko, P.; Stuart, M. C. A.; Browne, W. R.; Feringa, B. L.

    2017-01-01

    The concept of using chirality to dictate dimensions and to store chiral information in self-assembled nanotubes in a fully controlled manner is presented. We report a photoresponsive amphiphile that co-assembles with its chiral counterpart to form nanotubes and demonstrate how chirality can be used

  1. New possibilities for the gauging of chiral bosons

    CERN Document Server

    Abreu, Everton M C; Wotzasek, C; Abreu, Everton M. C.; Dutra, Alvaro de Souza; Wotzasek, Clovis

    2003-01-01

    We study a new mechanism for the electromagnetic gauging of chiral bosons showing that new possibilities emerge for the interacting theory of chiral scalars. We introduce a chirally coupled gauge field necessary to mod out the degree of freedom that obstructs gauge invariance in a system of two opposite chiral bosons soldering them together.

  2. Chiral transition with magnetic fields

    CERN Document Server

    Ayala, Alejandro; Mizher, Ana Julia; Rojas, Juan Cristobal; Villavicencio, Cristian

    2014-01-01

    We study the nature of the chiral transition for an effective theory with spontaneous breaking of symmetry, where charged bosons and fermions are subject to the effects of a constant external magnetic field. The problem is studied in terms of the relative intensity of the magnetic field with respect to the mass and the temperature. When the former is the smallest of the scales, we present a suitable method to obtain magnetic and thermal corrections up to ring order at high temperature. By these means, we solve the problem of the instability in the boson sector for these theories, where the squared masses, taken as functions of the order parameter, can vanish and even become negative. The solution is found by considering the screening properties of the plasma, encoded in the resummation of the ring diagrams at high temperature. We also study the case where the magnetic field is the intermediate of the three scales and explore the nature of the chiral transition as we vary the field strength, the coupling const...

  3. Chiral differential operators and topology

    CERN Document Server

    Cheung, Pokman

    2010-01-01

    The first part of this paper provides a new formulation of chiral differential operators (CDOs) in terms of global geometric quantities. The main result is a recipe to define essentially all sheaves of smooth CDOs on a cs-manifold; its ingredients consist of an affine connection and an even 3-form that trivializes the first Pontrjagin form. With the connection fixed, two suitable 3-forms define isomorphic sheaves of CDOs if and only if their difference is exact. Moreover, conformal structures are in one-to-one correspondence with even 1-forms that trivialize the first Chern form. The second part of this paper concerns the construction of what may be called "chiral Dolbeault complexes". The classical Dolbeault complex of a complex manifold M may be viewed as the functions on an associated cs-manifold with the action of an odd vector field Q that satisfies Q^2=0. Motivated by this, we study the condition under which a conformal sheaf of CDOs on that cs-manifold admits an odd derivation Q' that extends Q and sat...

  4. Nucleic acids, proteins, and chirality

    Science.gov (United States)

    Usher, D. A.; Profy, A. T.; Walstrum, S. A.; Needels, M. C.; Bulack, S. C.; Lo, K. M.

    1984-01-01

    The present investigation is concerned with experimental results related, in one case, to the chirality of nucleotides, and, in another case, to the possibility of a link between the chirality of nucleic acids, and that of peptides. It has been found that aminoacylation of the 'internal' hydroxyl group of a dinucleoside monophosphate can occur stereoselectively. However, this reaction has not yet been made a part of a working peptide synthesis scheme. The formation and cleavage of oligonucleotides is considered. In the event of the formation of a helical complex between the oligonucleotide and the polymer, 1-prime,5-prime-bonds in the oligomer are found to become more resistant towards cleavage. The conditions required for peptide bond formation are examined, taking into account the known structures of RNA and possible mechanisms for prebiotic peptide bond formation. The possibility is considered that the 2-prime,5-prime-internucleotide linkage could have played an important part in the early days of biological peptide synthesis.

  5. Nuclear chiral dynamics and thermodynamics

    CERN Document Server

    Holt, J W; Weise, W

    2013-01-01

    This presentation reviews an approach to nuclear many-body systems based on the spontaneously broken chiral symmetry of low-energy QCD. In the low-energy limit, for energies and momenta small compared to a characteristic symmetry breaking scale of order 1 GeV, QCD is realized as an effective field theory of Goldstone bosons (pions) coupled to heavy fermionic sources (nucleons). Nuclear forces at long and intermediate distance scales result from a systematic hierarchy of one- and two-pion exchange processes in combination with Pauli blocking effects in the nuclear medium. Short distance dynamics, not resolved at the wavelengths corresponding to typical nuclear Fermi momenta, are introduced as contact interactions between nucleons. Apart from a set of low-energy constants associated with these contact terms, the parameters of this theory are entirely determined by pion properties and low-energy pion-nucleon scattering observables. This framework (in-medium chiral perturbation theory) can provide a realistic des...

  6. Chlorophylls, Symmetry, Chirality, and Photosynthesis

    Directory of Open Access Journals (Sweden)

    Mathias O. Senge

    2014-09-01

    Full Text Available Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.

  7. Chiral Ionic Liquids in Chromatographic Separation and Spectroscopic Discrimination

    Science.gov (United States)

    Li, Min; Bwambok, David K.; Fakayode, Sayo O.; Warner, Isiah M.

    Chiral ionic liquids (CILs) are a subclass of ionic liquids (ILs) in which the cation, anion, or both may be chiral. The chirality can be central, axial, or planar. CILs possess a number of unique advantageous properties which are inherited from ionic liquids including negligible vapor pressure, wide liquidus temperature range, high thermal stability, and high tunability. Due to their dual functionalities as chiral selectors and chiral solvents simultaneously, CILs recently have been widely used both in enantiomeric chromatographic separation and in chiral spectroscopic discrimination. In this chapter, the various applications of CILs in chiral chromatographic separations such as GC, HPLC, CE, and MEKC are reviewed. The applications of CILs in enantiomeric spectroscopic discrimination using techniques such as NMR, fluorescence, and NIR are described. In addition, chiral recognition and separation mechanism using the CILs as chiral selectors or chiral solvents is also discussed.

  8. Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite.

    Science.gov (United States)

    Engel, M H; Macko, S A

    1997-09-18

    Many amino acids contain an asymmetric centre, occurring as laevorotatory, L, or dextrorotatory, D, compounds. It is generally assumed that abiotic synthesis of amino acids on the early Earth resulted in racemic mixtures (L- and D-enantiomers in equal abundance). But the origin of life required, owing to conformational constraints, the almost exclusive selection of either L- or D-enantiomers, and the question of why living systems on the Earth consist of L-enantiomers rather than D-enantiomers is unresolved. A substantial fraction of the organic compounds on the early Earth may have been derived from comet and meteorite impacts. It has been reported previously that amino acids in the Murchison meteorite exhibit an excess of L-enantiomers, raising the possibility that a similar excess was present in the initial inventory of organic compounds on the Earth. The stable carbon isotope compositions of individual amino acids in Murchison support an extraterrestrial origin -- rather than a terrestrial overprint of biological amino acids-although reservations have persisted. Here we show that individual amino-acid enantiomers from Murchison are enriched in 15N relative to their terrestrial counterparts, so confirming an extraterrestrial source for an L-enantiomer excess in the Solar System that may predate the origin of life on the Earth.

  9. Spontaneous Planar Chiral Symmetry Breaking in Cells

    Science.gov (United States)

    Hadidjojo, Jeremy; Lubensky, David

    Recent progress in animal development has highlighted the central role played by planar cell polarity (PCP) in epithelial tissue morphogenesis. Through PCP, cells have the ability to collectively polarize in the plane of the epithelium by localizing morphogenetic proteins along a certain axis. This allows direction-dependent modulation of tissue mechanical properties that can translate into the formation of complex, non-rotationally invariant shapes. Recent experimental observations[1] show that cells, in addition to being planar-polarized, can also spontaneously develop planar chirality, perhaps in the effort of making yet more complex shapes that are reflection non-invariant. In this talk we will present our work in characterizing general mechanisms that can lead to spontaneous chiral symmetry breaking in cells. We decompose interfacial concentration of polarity proteins in a hexagonal cell packing into irreducible representations. We find that in the case of polar concentration distributions, a chiral state can only be reached from a secondary instability after the cells are polarized. However in the case of nematic distributions, we show that a finite-amplitude (subcritical, or ``first-order'') nematic transition can send the system from disorder directly to a chiral state. In addition, we find that perturbing the system by stretching the hexagonal packing enables direct (supercritical, or ``second-order'') chiral transition in the nematic case. Finally, we do a Landau expansion to study competition between stretch-induced chirality and the tendency towards a non-chiral state in packings that have retained the full 6-fold symmetry.

  10. New Chiral Calixarene Derivatives: Syntheses and Their Chiral Recognition Toward Amino Acids by UV-Vis Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Three novel types of chiral calixarene derivatives 5, 8, and 10 were designed and synthesized by introducing chiral units to parent calixarenes. Their chiralities were confirmed by rotational analysis. Chiral recognition properties of these host compounds towards L- and D-threonine were studied by UV-Vis spectroscopy. The results indicated that calixarene derivatives 5 and 8 exhibited good chiral recognition capabilities toward L- or D-threonine. Although calixarene derivative 10 had no evident chiral recognition ability, the supramolecules of calixarene derivative 10 with L- or D-threonine showed a hypochromic effect or hyperchromic effect respectively. Therefore, calixarene derivative 10 might serve as a good chiral UV-indicator.

  11. Dirac operator normality and chiral properties

    Science.gov (United States)

    Kerler, W.

    Normality and γ5-hermiticity are what gives rise to chiral properties and rules. The Ginsparg-Wilson (GW) relation is only one of the possible spectral constraints. The sum rule for chiral differences of real modes has important consequences. The alternative transformation of Lüscher gives the same Ward identity as the usual chiral one (if zero modes are properly treated). Imposing normality on a general function of the hermitean Wilson-Dirac operator H leads at same time to the GW relation and to the Neuberger operator.

  12. Enhanced Chiral Recognition by Cyclodextrin Dimers

    Directory of Open Access Journals (Sweden)

    Bart Jan Ravoo

    2011-07-01

    Full Text Available In this article we investigate the effect of multivalency in chiral recognition. To this end, we measured the host-guest interaction of a β-cyclodextrin dimer with divalent chiral guests. We report the synthesis of carbohydrate-based water soluble chiral guests functionalized with two borneol, menthol, or isopinocampheol units in either (+ or (– configuration. We determined the interaction of these divalent guests with a β-cyclodextrin dimer using isothermal titration calorimetry. It was found that—in spite of a highly unfavorable conformation—the cyclodextrin dimer binds to guest dimers with an increased enantioselectivity, which clearly reflects the effect of multivalency.

  13. Interplay between Deconfinement and Chiral Properties

    CERN Document Server

    Suganuma, Hideo; Redlich, Krzysztof; Sasaki, Chihiro

    2016-01-01

    We study interplay between confinement/deconfinement and chiral properties. We derive some analytical relations of the Dirac modes with the confinement quantities, such as the Polyakov loop, its susceptibility and the string tension. For the confinement quantities, the low-lying Dirac eigenmodes are found to give negligible contribution, while they are essential for chiral symmetry breaking. This indicates no direct, one-to-one correspondence between confinement/deconfinement and chiral properties in QCD. We also investigate the Polyakov loop in terms of the eigenmodes of the Wilson, the clover and the domain-wall fermion kernels, respectively.

  14. Biocatalysis: synthesis of chiral intermediates for drugs.

    Science.gov (United States)

    Patel, Ramesh N

    2006-11-01

    Chirality is a key factor in the safety and efficacy of many drug products and thus the production of single enantiomers of drug intermediates has become increasingly important in the pharmaceutical industry. Chiral intermediates and fine chemicals are in high demand for the bulk preparation of drug substances and agricultural products. There has been an increasing awareness of the enormous potential of the use of microorganisms and microorganism-derived enzymes for the transformation of synthetic chemicals with high chemo-, regio- and enantioselectivities. In this article, biocatalytic processes are described for the synthesis of chiral intermediates for drugs.

  15. The convoluted evolution of snail chirality

    Science.gov (United States)

    Schilthuizen, M.; Davison, A.

    2005-11-01

    The direction that a snail (Mollusca: Gastropoda) coils, whether dextral (right-handed) or sinistral (left-handed), originates in early development but is most easily observed in the shell form of the adult. Here, we review recent progress in understanding snail chirality from genetic, developmental and ecological perspectives. In the few species that have been characterized, chirality is determined by a single genetic locus with delayed inheritance, which means that the genotype is expressed in the mother's offspring. Although research lags behind the studies of asymmetry in the mouse and nematode, attempts to isolate the loci involved in snail chirality have begun, with the final aim of understanding how the axis of left-right asymmetry is established. In nature, most snail taxa (>90%) are dextral, but sinistrality is known from mutant individuals, populations within dextral species, entirely sinistral species, genera and even families. Ordinarily, it is expected that strong frequency-dependent selection should act against the establishment of new chiral types because the chiral minority have difficulty finding a suitable mating partner (their genitalia are on the ‘wrong’ side). Mixed populations should therefore not persist. Intriguingly, however, a very few land snail species, notably the subgenus Amphidromus sensu stricto, not only appear to mate randomly between different chiral types, but also have a stable, within-population chiral dimorphism, which suggests the involvement of a balancing factor. At the other end of the spectrum, in many species, different chiral types are unable to mate and so could be reproductively isolated from one another. However, while empirical data, models and simulations have indicated that chiral reversal must sometimes occur, it is rarely likely to lead to so-called ‘single-gene’ speciation. Nevertheless, chiral reversal could still be a contributing factor to speciation (or to divergence after speciation) when

  16. Critical Temperature of Chiral Symmetry Restoration for Quark Matter with a Chiral Chemical Potential

    CERN Document Server

    Ruggieri, M

    2016-01-01

    In this article we study restoration of chiral symmetry at finite temperature for quark matter with a chiral chemical potential, $\\mu_5$, by means of a quark-meson model with vacuum fluctuations included. Vacuum fluctuations give a divergent contribution to the vacuum energy, so the latter has to be renormalized before computing physical quantities. The vacuum term is important for restoration of chiral symmetry at finite temperature and $\\mu_5\

  17. Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

    Energy Technology Data Exchange (ETDEWEB)

    Kalaydzhyan, Tigran, E-mail: tigran@caltech.edu [Department of Physics, University of Illinois, 845 W Taylor Street, Chicago, IL 60607 (United States); Jet Propulsion Laboratory, 4800 Oak Grove Dr, M/S 298, Pasadena, CA 91109 (United States); Murchikova, Elena [TAPIR, California Institute of Technology, MC 350-17, Pasadena, CA 91125 (United States)

    2017-06-15

    In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark–gluon plasma, liquid helium {sup 3}He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiral magnetic waves) and transverse velocity (chiral Alfvén wave). We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.

  18. New Chiral Metal Cluster Systems for Catalytic Asymmetric Syntheses of Chiral Alcohols

    Institute of Scientific and Technical Information of China (English)

    LI Yan-yun; CHEN Jian-shan; YANG Chuan-bo; DONG Zhen-rong; LI Bao-zhu; ZHANG Hui; GAO Jing-xing; TAKAO Ikariya

    2004-01-01

    The efficient chiral Ru3(CO)12 systems were prepared in situ from Ru3(CO)12 and various chiral diiminoor diamino-diphosphine tetradentate ligands. The systems have been used for the asymmetric transfer hydrogenation of propiophenone in 2-propanol, leading to 1-phenyl-1-propanol in a 98% yield and 96% e.e. The IR study suggests that the carbonyl hydride anion [HRu3(CO)11]- most probably exists as a principal species under the reaction conditions. The high chiral efficiency may be due to the synergetic effect produced by the neighboring ruthenium atoms and a special chiral micro-environment involving the polydentate ligand and the Ru3 framework.

  19. Resolution of the Chiral Drugs

    Institute of Scientific and Technical Information of China (English)

    DENG JinGen; ZHU Jin

    2001-01-01

    @@ Chiral drugs are generally not permitted to be used in racemic form so that unintended side effects and unnecessary environmental hazards are avoided. Moreover, homochiral molecules are required immediately to progress key toxicological and clinical studies in the drug discovery. One series of technologies which can rapidly supply homochiral compounds is the separation of racemates, and of those the technique of crystallization of diastereomers is extremely effective-principally because it is simple to operate and it affords both enantiomers. In classical resolution via diastereoisomeric salt formation, the resolved compounds are limited to a given racemic acid or base and the choice of a suitable resolving agent for a racemic target compound is achieved by time-consuming trial-and-error procedure.

  20. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  1. Chiral exceptional points in metasurfaces

    Science.gov (United States)

    Kang, Ming; Chen, Jing; Chong, Y. D.

    2016-09-01

    An exceptional point (EP) is a degeneracy occurring in a non-energy-conserving system, in which two eigenvectors of a non-Hermitian Hamiltonian coalesce. We explore how EPs can be realized in a metamaterial surface, or metasurface, consisting of a pair of lossy coupled linear antennas in each unit cell. EPs appear in the eigenvectors of the transmission matrix by tuning the frequency and the coupling and loss rates of the metasurface. Each EP is associated with the appearance of a circularly polarized transmission eigenstate; hence, within the parameter space of the system, the EPs lie along pairs of curves with distinct chirality. Our results are obtained using finite-difference time-domain simulations, as well as a fitted coupled-mode theory. The coupled-mode theory agrees well with the numerical results and is capable of accurately predicting the EP f curves.

  2. Resolution of the Chiral Drugs

    Institute of Scientific and Technical Information of China (English)

    DENG; JinGen

    2001-01-01

    Chiral drugs are generally not permitted to be used in racemic form so that unintended side effects and unnecessary environmental hazards are avoided. Moreover, homochiral molecules are required immediately to progress key toxicological and clinical studies in the drug discovery. One series of technologies which can rapidly supply homochiral compounds is the separation of racemates, and of those the technique of crystallization of diastereomers is extremely effective-principally because it is simple to operate and it affords both enantiomers. In classical resolution via diastereoisomeric salt formation, the resolved compounds are limited to a given racemic acid or base and the choice of a suitable resolving agent for a racemic target compound is achieved by time-consuming trial-and-error procedure.  ……

  3. Chiral transition of fundamental and adjoint quarks

    Energy Technology Data Exchange (ETDEWEB)

    Capdevilla, R.M. [Instituto de Física Teórica, UNESP – Universidade Estadual Paulista, Rua Dr. Bento T. Ferraz, 271, Bloco II, 01140-070 São Paulo, SP (Brazil); Doff, A., E-mail: agomes@utfpr.edu.br [Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR (Brazil); Natale, A.A., E-mail: natale@ift.unesp.br [Instituto de Física Teórica, UNESP – Universidade Estadual Paulista, Rua Dr. Bento T. Ferraz, 271, Bloco II, 01140-070 São Paulo, SP (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil)

    2014-01-20

    The chiral symmetry breaking transition of quarks in the fundamental and adjoint representation is studied in a model where the gap equation contains two contributions, one containing a confining propagator and another corresponding to the exchange of one-dressed dynamically massive gluons. When quarks are in the fundamental representation the confinement effect dominates the chiral symmetry breaking while the gluon exchange is suppressed due to the dynamical gluon mass effect in the propagator and in the coupling constant. In this case the chiral and deconfinement transition temperatures are approximately the same. For quarks in the adjoint representation, due to the larger Casimir eigenvalue, the gluon exchange is operative and the chiral transition happens at a larger temperature than the deconfinement one.

  4. Pasteur and the art of chirality

    Science.gov (United States)

    Gal, Joseph

    2017-07-01

    Louis Pasteur was a scientific giant of the nineteenth century, but, as Joseph Gal asks, was his most famous contribution to the understanding of chemistry -- chirality -- influenced more by his artistic talents?

  5. Enzymic synthesis of labelled chiral substances.

    Science.gov (United States)

    Battersby, A R

    1985-01-01

    The enzymic synthesis of chiral substances in which one hydrogen atom of a methylene group has been replaced by deuterium or tritium is illustrated. Such labelled products can be used to determine the stereochemistry of other enzyme-catalysed reactions.

  6. New Advances in Chiral Catalyst Immobilization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Asymmetric catalysis of organic reactions is one of the most efficient ways to obtain optically pure chiral compounds, which are crucially important to the development of modern pharmaceutical and fine chemical industries, as well as material science.

  7. Notes on conservation laws in chiral hydrodynamics

    CERN Document Server

    Zakharov, V I

    2016-01-01

    We consider chiral fluids within the standard framework of a chiral-invariant underlying field theory, anomalous in presence of electromagnetic fields. Apart from the Noether axial current of the underlying theory, in the limit of ideal fluid there exist extra conserved currents, corresponding to classical helical motions. The extra conservation laws are known to break down once viscosity is non-vanishing. Which looks puzzling, as if introduction of viscosity were inconsistent with chiral invariance. As a resolution of the puzzle, we argue that locally one can introduce an inertial frame where an extra conservation law still holds. In other words, the extra currents are covariantly conserved. The emergent gravitational field is determined by dynamics of the viscous fluid. We turn then to instabilities of chiral plasma against decays into helical magnetic or vortical configurations. We emphasise similarity between the two cases in the far infrared region, responsible for the decays. This similarity is not appa...

  8. Chirality in thiolate-protected gold clusters.

    Science.gov (United States)

    Knoppe, Stefan; Bürgi, Thomas

    2014-04-15

    Over recent years, research on thiolate-protected gold clusters Au(m)(SR)n has gained significant interest. Milestones were the successful determination of a series of crystal structures (Au102(SR)44, Au25(SR)18, Au38(SR)24, Au36(SR)24, and Au28(SR)20). For Au102(SR)44, Au38(SR)24, and Au28(SR)20, intrinsic chirality was found. Strong Cotton effects (circular dichroism, CD) of gold clusters protected by chiral ligands have been reported a long time ago, indicating the transfer of chiral information from the ligand into the cluster core. Our lab has done extensive studies on chiral thiolate-protected gold clusters, including those protected with chiral ligands. We demonstrated that vibrational circular dichroism can serve as a useful tool for the determination of conformation of the ligand on the surface of the cluster. The first reports on crystal structures of Au102(SR)44 and Au38(SR)24 revealed the intrinsic chirality of these clusters. Their chirality mainly arises from the arrangement of the ligands on the surface of the cluster cores. As achiral ligands are used to stabilize the clusters, racemic mixtures are obtained. However, the separation of the enantiomers by HPLC was demonstrated which enabled the measurement of their CD spectra. Thermally induced inversion allows determination of the activation parameters for their racemization. The inversion demonstrates that the gold-thiolate interface is anything but fixed; in contrast, it is rather flexible. This result is of fundamental interest and needs to be considered in future applications. A second line of our research is the selective introduction of chiral, bidentate ligands into the ligand layer of intrinsically chiral gold clusters. The ligand exchange reaction is highly diastereoselective. The bidentate ligand connects two of the protecting units on the cluster surface and thus effectively stabilizes the cluster against thermally induced inversion. A minor (but significant) influence of chiral ligands to

  9. Development of safer molecules through chirality

    Directory of Open Access Journals (Sweden)

    Patil P

    2006-10-01

    Full Text Available Many of the drugs currently used in medical practice are mixtures of enantiomers (racemates. Many a times, the two enantiomers differ in their pharmacokinetic and pharmacodynamic properties. Replacing existing racemates with single isomers has resulted in improved safety and/or efficacy profile of various racemates. In this review, pharmacokinetic and pharmacodynamic implications of chirality are discussed in brief, followed by an overview of some important chiral switches that have yielded safer alternatives. These include levosalbutamol, S-ketamine, levobupivacaine, S-zopiclone, levocetirizine, S-amlodipine, S-atenolol, S-metoprolol, S-omeprazole, S-pantoprazole and R-ondansetron. Few potential chiral switches under evaluation and some chiral switches that have not been successful are also discussed.

  10. Random matrix model approach to chiral symmetry

    CERN Document Server

    Verbaarschot, J J M

    1996-01-01

    We review the application of random matrix theory (RMT) to chiral symmetry in QCD. Starting from the general philosophy of RMT we introduce a chiral random matrix model with the global symmetries of QCD. Exact results are obtained for universal properties of the Dirac spectrum: i) finite volume corrections to valence quark mass dependence of the chiral condensate, and ii) microscopic fluctuations of Dirac spectra. Comparisons with lattice QCD simulations are made. Most notably, the variance of the number of levels in an interval containing $n$ levels on average is suppressed by a factor $(\\log n)/\\pi^2 n$. An extension of the random matrix model model to nonzero temperatures and chemical potential provides us with a schematic model of the chiral phase transition. In particular, this elucidates the nature of the quenched approximation at nonzero chemical potential.

  11. Chiral Magnetic Effect in Heavy Ion Collisions

    CERN Document Server

    Liao, Jinfeng

    2016-01-01

    The Chiral Magnetic Effect (CME) is a remarkable phenomenon that stems from highly nontrivial interplay of QCD chiral symmetry, axial anomaly, and gluonic topology. It is of fundamental importance to search for the CME in experiments. The heavy ion collisions provide a unique environment where a hot chiral-symmetric quark-gluon plasma is created, gluonic topological fluctuations generate chirality imbalance, and very strong magnetic fields $|\\vec{\\bf B}|\\sim m_\\pi^2$ are present during the early stage of such collisions. Significant efforts have been made to look for CME signals in heavy ion collision experiments. In this contribution we give a brief overview on the status of such efforts.

  12. Chirality and angular momentum in optical radiation

    CERN Document Server

    Coles, Matt M

    2012-01-01

    This paper develops, in precise quantum electrodynamic terms, photonic attributes of the "optical chirality density", one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends insights into some recent interpretations of chiroptical experiments, in which this measure, and an associated chirality flux, have been treated as representing physically distinctive "superchiral" phenomena. In the fully quantized formalism the chirality density is promoted to operator status, whose exploration with reference to an arbitrary polarization basis reveals relationships to optical angular momentum and helicity operators. Analyzing multi-mode beams with complex wave-front structures, notably Laguerre-Gaussian modes, affords a deeper understanding of the interplay between optical chirality and optical angular momentum. By developing theory with due cognizance of the photonic character of light, it emerges that only the spin angular momentum of light is engaged in such...

  13. Organocatalytic atroposelective synthesis of axially chiral styrenes

    Science.gov (United States)

    Zheng, Sheng-Cai; Wu, San; Zhou, Qinghai; Chung, Lung Wa; Ye, Liu; Tan, Bin

    2017-05-01

    Axially chiral compounds are widespread in biologically active compounds and are useful chiral ligands or organocatalysts in asymmetric catalysis. It is well-known that styrenes are one of the most abundant and principal feedstocks and thus represent excellent prospective building blocks for chemical synthesis. Driven by the development of atroposelective synthesis of axially chiral styrene derivatives, we discovered herein the asymmetric organocatalytic approach via direct Michael addition reaction of substituted diones/ketone esters/malononitrile to alkynals. The axially chiral styrene compounds were produced with good chemical yields, enantioselectivities and almost complete E/Z-selectivities through a secondary amine-catalysed iminium activation strategy under mild conditions. Such structural motifs are important precursors for further transformations into biologically active compounds and synthetic useful intermediates and may have potential applications in asymmetric synthesis as olefin ligands or organocatalysts.

  14. Chiral dynamics with (non)strange quarks

    Science.gov (United States)

    Kubis, Bastian; Meißner, Ulf-G.

    2017-01-01

    We review the results and achievements of the project B.3. Topics addressed include pion photoproduction off the proton and off deuterium, three-flavor chiral perturbation theory studies, chiral symmetry tests in Goldstone boson decays, the development of unitarized chiral perturbation theory to next-to-leading order, the two-pole structure of the Λ(1405), the dynamical generation of the lowest S11 resonances, the theory of hadronic atoms and its application to various systems, precision studies in light-meson decays based on dispersion theory, the Roy-Steiner analysis of pion-nucleon scattering, a high-precision extraction of the elusive pion-nucleon σ-term, and aspects of chiral dynamics in few-nucleon systems.

  15. NN Interaction in Chiral Constituent Quark Models

    CERN Document Server

    Valcarce, A; González, P

    2003-01-01

    We review the actual state in the description of the NN interaction by means of chiral constituent quark models. We present a series of relevant features that are nicely explained within the quark model framework.

  16. Large Enhancement of Circular Dichroism Using an Embossed Chiral Metamaterial

    CERN Document Server

    Mousavi, S Hamed Shams; El-Sayed, Mostafa A; Eftekhar, Ali A; Adibi, Ali

    2016-01-01

    In the close vicinity of a chiral nanostructure, the circular dichroism of a biomolecule could be greatly enhanced, due to the interaction with the local superchiral fields. Modest enhancement of optical activity using a planar metamaterial, with some chiral properties, and achiral nanoparticles has been previously reported. A more substantial chirality enhancement can be achieved in the local filed of a chiral nanostructure with a three-dimensional arrangement. Using an embossed chiral nanostructure designed for chiroptical sensing, we measure the circular dichroism spectra of two biomolecules, Chlorophylls A and B, at the molecular level, using a simple polarization resolved reflection measurement. This experiment is the first realization of the on-resonance surface-enhanced circular dichroism, achieved by matching the chiral resonances of a strongly chiral metamaterial with that of a chiral molecule, resulting in an unprecedentedly large differential CD spectrum from a monolayer of a chiral material.

  17. Bringing chiral optical forces to dominance with optical nanofibers

    CERN Document Server

    Alizadeh, M H

    2016-01-01

    Transverse spin angular momentum (SAM) of light and associated transverse chiral optical forces have received tremendous attention recently as the latter may lead to an optical separation of chiral biomolecules. Previous schemes to generate chiral forces are plagued by the fact that the chiral optical forces are orders of magnitude smaller than conventional gradient and scattering forces. The relative magnitude of chiral and non-chiral forces represents a fundamental challenge for the implementation of chiral separation schemes. In this work we demonstrate that, by spatially separating the maxima of transverse spin density from the gradient of field intensity, in the vicinity of optical nanofibers and nanowires, chiral optical forces can emerge that are stronger than gradient and scattering forces. This finding has important implications for the design of improved optical separation schemes for chiral biomolecules.

  18. Insights on some chiral smectic phases

    Indian Academy of Sciences (India)

    B Pansu

    2003-08-01

    Combining layered positional order as smectic order and chirality can generate complex architectures since twist parallel to the layers is not allowed. This paper will review some new experimental results on different phases resulting from the competition between smectic positional order and twist orientational order. It concerns the TGBA and the NL*, that is the liquid line phase as well as the SmQ phase. Chiral effects in the isotropic phase will also be discussed.

  19. Open Problems in Understanding the Nuclear Chirality

    CERN Document Server

    Meng, Jie

    2010-01-01

    Open problems in the interpretation of the observed pair of near degenerate $\\Delta I = 1$ bands with the same parity as the chiral doublet bands are discussed. The ambiguities for the existing fingerprints of the chirality in atomic nuclei and problems in existing theory are discussed, including the description of quantum tunneling in the mean field approximation as well as the deformation, core polarization and configuration of particle rotor model (PRM). Future developments of the theoretical approach are prospected.

  20. Chiral symmetry and lattice gauge theory

    CERN Document Server

    Creutz, M

    1994-01-01

    I review the problem of formulating chiral symmetry in lattice gauge theory. I discuss recent approaches involving an infinite tower of additional heavy states to absorb Fermion doublers. For hadronic physics this provides a natural scheme for taking quark masses to zero without requiring a precise tuning of parameters. A mirror Fermion variation provides a possible way of extending the picture to chirally coupled light Fermions. Talk presented at "Quark Confinement and the Hadron Spectrum," Como, Italy, 20-24 June 1994.

  1. Development of safer molecules through chirality

    OpenAIRE

    Patil P; Kothekar M

    2006-01-01

    Many of the drugs currently used in medical practice are mixtures of enantiomers (racemates). Many a times, the two enantiomers differ in their pharmacokinetic and pharmacodynamic properties. Replacing existing racemates with single isomers has resulted in improved safety and/or efficacy profile of various racemates. In this review, pharmacokinetic and pharmacodynamic implications of chirality are discussed in brief, followed by an overview of some important chiral switches that have yielded ...

  2. A liquid crystalline chirality balance for vapours

    OpenAIRE

    Ohzono, Takuya; Yamamoto, Takahiro; Fukuda, Jun-Ichi

    2014-01-01

    Chiral discrimination of vapours plays an important role in olfactory perception of biological systems and its realization by artificial sensors has been an intriguing challenge. Here, we report a simple method that tangibly visualizes the chirality of a diverse variety of molecules dissolved from vapours with high sensitivity, by making use of a structural change in a periodic microstructure of a nematic liquid crystal confined in open microchannels. This microstructure is accompanied by a t...

  3. The Chiral Dipolar Hard Sphere Model.

    OpenAIRE

    Mazars, Martial

    2009-01-01

    Abstract A simple molecular model of chiral molecules is presented in this paper : the chiral dipolar hard sphere model. The discriminatory interaction between enantiomers is represented by electrostatic (or magnetic) dipoles-dipoles interactions : short ranged steric repulsion are represented by hard sphere potential and, in each molecule, two point dipoles are located inside the sphere. The model is described in detail and some of its elementary properties are given ; in particul...

  4. On the covariantization of the chiral constraints

    CERN Document Server

    Neves, C; Wotzasek, C; Neves, C; de Abreu, E M C; Wotzasek, C

    1995-01-01

    We show that a complete covariantization of the chiral constraint in the Floreanini-Jackiw necessitates an infinite number of auxiliary Wess-Zumino fields otherwise the covariantization is only partial and unable to remove the nonlocality in the chiral boson operator. We comment on recent works that claim to obtain covariantization through the use of Batalin-Fradkin-Tyutin method, that uses just one Wess-Zumino field.

  5. Chiral symmetry and the constituent quark model

    CERN Document Server

    Glozman, L Ya

    1995-01-01

    New results on baryon structure and spectrum developed in collaboration with Dan Riska [1-4] are reported. The main idea is that beyond the chiral symmetry spontaneous breaking scale light and strange baryons should be considered as systems of three constituent quarks with an effective confining interaction and a chiral interaction that is mediated by the octet of Goldstone bosons (pseudoscalar mesons) between the constituent quarks.

  6. Baryons in chiral constituent quark model

    CERN Document Server

    Glozman, L Ya

    1996-01-01

    Beyond the spontaneous chiral symmetry breaking scale light and strange baryons should be considered as systems of three constituent quarks with an effective confining interaction and a flavor-spin chiral interaction that is mediated by the octet of Goldstone bosons (pseudoscalar mesons) between the constituent quarks. One cannot exclude, however, the possibility that this flavor-spin interaction has an appreciable vector- and higher meson exchange component.

  7. Lattice quantum chromodynamics with approximately chiral fermions

    Energy Technology Data Exchange (ETDEWEB)

    Hierl, Dieter

    2008-05-15

    In this work we present Lattice QCD results obtained by approximately chiral fermions. We use the CI fermions in the quenched approximation to investigate the excited baryon spectrum and to search for the {theta}{sup +} pentaquark on the lattice. Furthermore we developed an algorithm for dynamical simulations using the FP action. Using FP fermions we calculate some LECs of chiral perturbation theory applying the epsilon expansion. (orig.)

  8. A Molecular Model for Chiral Symmetry Breaking

    Science.gov (United States)

    Latinwo, Folarin; Stillinger, Frank; Debenedetti, Pablo

    In this work, we present a new class of molecular models for chiral phenomena in condensed matter systems. A key feature of these models is the ability of the four-site (tetramer) ``molecules'' to inter-convert between two distinct chiral forms (enantiomers). Given this feature, we use analytical theory and computer simulations to investigate the emergent chiral properties (including symmetry breaking) over a range of conditions. In particular, we consider the single-molecule level and condensed-phase behavior of our model system. Interestingly, we find that our liquid-phase predictions are in excellent agreement with recent experimental reports on chiral self-sorting in isotropic liquids. From this perspective, our model demonstrates accurate predictive capabilities, as well as a platform for understanding the microscopic origins of a variety of chiral phenomena. In a broader context, we anticipate that this class of models will be relevant to chirality-dominated areas such as the pharmaceutical industry and pre-biotic geochemistry.

  9. Chirality and chiroptical properties of amyloid fibrils.

    Science.gov (United States)

    Dzwolak, Wojciech

    2014-09-01

    Chirality of amyloid fibrils-linear beta-sheet-rich aggregates of misfolded protein chains-often manifests in morphological traits such as helical twist visible in atomic force microscopy and in chiroptical properties accessible to vibrational circular dichroism (VCD). According to recent studies the relationship between molecular chirality of polypeptide building blocks and superstructural chirality of amyloid fibrils may be more intricate and less deterministic than previously assumed. Several puzzling experimental findings have put into question earlier intuitive ideas on: 1) the bottom-up chirality transfer upon amyloidogenic self-assembly, and 2) the structural origins of chiroptical properties of protein aggregates. For example, removal of a single amino acid residue from an amyloidogenic all-L peptide was shown to reverse handedness of fibrils. On the other hand, certain types of amyloid aggregates revealed surprisingly strong VCD spectra with the sign and shape dependent on the conditions of fibrillation. Hence, microscopic and chiroptical studies have highlighted chirality as one more aspect of polymorphism of amyloid fibrils. This brief review is intended to outline the current state of research on amyloid-like fibrils from the perspective of their structural and superstructural chirality and chiroptical properties.

  10. Miniaturized Lab-on-a-Chip Polarimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Life on Earth is unique in many ways; one of its great mysteries is that all the biomolecules of Earth's life are chiral and non-racemic. In our pursuit of life on...

  11. Developing a Practical Chiral Toolbox for Asymmetric Catalytic Reactions

    Institute of Scientific and Technical Information of China (English)

    ZHANG XuMu

    2001-01-01

    @@ Chiral Quest's Toolbox Approach: During the last several decades, chemists have made major progress in discovering man-made catalysts to perform challenging asymmetric transformations. However, there is no universal chiral ligand or catalyst for solving problems in enantioselective transformations. The focus of Chiral Quest's research is to develop a useful chiral toolbox for strategically important asymmetric catalytic reactions by inventing a diverse set of novel chiral ligands and combining them with transition metals as effective enantioselective catalysts. The toolbox approach addresses significant problems in organic stereochemistry and has resulted in practical methods for the synthesis of chiral pharmaceuticals and agrochemicals

  12. Developing a Practical Chiral Toolbox for Asymmetric Catalytic Reactions

    Institute of Scientific and Technical Information of China (English)

    ZHANG; XuMu

    2001-01-01

    Chiral Quest's Toolbox Approach: During the last several decades, chemists have made major progress in discovering man-made catalysts to perform challenging asymmetric transformations. However, there is no universal chiral ligand or catalyst for solving problems in enantioselective transformations. The focus of Chiral Quest's research is to develop a useful chiral toolbox for strategically important asymmetric catalytic reactions by inventing a diverse set of novel chiral ligands and combining them with transition metals as effective enantioselective catalysts. The toolbox approach addresses significant problems in organic stereochemistry and has resulted in practical methods for the synthesis of chiral pharmaceuticals and agrochemicals  ……

  13. Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

    Science.gov (United States)

    Guo, Zhen; Du, Yu; Liu, Xianbin; Ng, Siu-Choon; Chen, Yuan; Yang, Yanhui

    2010-04-01

    Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

  14. Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 (Singapore); Du Yu, E-mail: du_yu@jlu.edu.cn, E-mail: yhyang@ntu.edu.sg [College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2010-04-23

    Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

  15. The asymmetric alkylation of dimethylhydrazones; intermolecular chirality transfer using sparteine as chiral ligand.

    Science.gov (United States)

    McSweeney, Christina M; Foley, Vera M; McGlacken, Gerard P

    2014-12-01

    The asymmetric alkylation of ketones represents a fundamental transformation in organic chemistry. Chiral auxiliaries have been used almost exclusively for this transformation. Herein we describe a strategy for the generation of enantiomerically enriched α-alkylated ketones up to an er of 83 : 17, using a chiral ligand protocol.

  16. Novel electrochemical method for the characterization of the degree of chirality in chiral polyaniline.

    Science.gov (United States)

    Feng, Zhang; Li, Ma; Yan, Yang; Jihai, Tang; Xiao, Li; Wanglin, Li

    2013-01-01

    A novel method to indicate the degree of chirality in polyaniline (PANI) was developed. The (D-camphorsulfonic acid)- and (HCl)-PANI-based electrodes exhibited significantly different electrochemical performances in D- and L-Alanine (Ala) aqueous solution, respectively, which can be used for the characterization the optical activity of chiral PANI. Cyclic voltammogram, tafel, and open circuit potential of PANI-based electrodes were measured within D- and L-Ala electrolyte solution, respectively. The open circuit potentials under different reacting conditions were analyzed by Doblhofer model formula, in which [C(+)](poly1)/[C(+)](poly2) was used as a parameter to characterize the degree of chirality in chiral PANI. The results showed that [C(+)](poly1)/[C(+)](poly2) can be increased with increasing concentrations of (1S)-(+)- and (1R)-(-)-10-camphorsulfonic acid. In addition, we detected that appropriate response time and lower temperature are necessary to improve the degree of chirality.

  17. Chiral dynamics and peripheral transverse densities

    Energy Technology Data Exchange (ETDEWEB)

    Granados, Carlos G. [Uppsala University (Sweden); Weiss, Christian [JLAB, Newport News, VA (United States)

    2014-01-01

    In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.

  18. Diffusion of active chiral particles

    Science.gov (United States)

    Sevilla, Francisco J.

    2016-12-01

    The diffusion of chiral active Brownian particles in three-dimensional space is studied analytically, by consideration of the corresponding Fokker-Planck equation for the probability density of finding a particle at position x and moving along the direction v ̂ at time t , and numerically, by the use of Langevin dynamics simulations. The analysis is focused on the marginal probability density of finding a particle at a given location and at a given time (independently of its direction of motion), which is found from an infinite hierarchy of differential-recurrence relations for the coefficients that appear in the multipole expansion of the probability distribution, which contains the whole kinematic information. This approach allows the explicit calculation of the time dependence of the mean-squared displacement and the time dependence of the kurtosis of the marginal probability distribution, quantities from which the effective diffusion coefficient and the "shape" of the positions distribution are examined. Oscillations between two characteristic values were found in the time evolution of the kurtosis, namely, between the value that corresponds to a Gaussian and the one that corresponds to a distribution of spherical shell shape. In the case of an ensemble of particles, each one rotating around a uniformly distributed random axis, evidence is found of the so-called effect "anomalous, yet Brownian, diffusion," for which particles follow a non-Gaussian distribution for the positions yet the mean-squared displacement is a linear function of time.

  19. Magnetohydrodynamics of Chiral Relativistic Fluids

    CERN Document Server

    Boyarsky, Alexey; Ruchayskiy, Oleg

    2015-01-01

    We study the dynamics of a plasma of charged relativistic fermions at very high temperature $T\\gg m$, where $m$ is the fermion mass, coupled to the electromagnetic field. In particular, we derive a magneto-hydrodynamical description of the evolution of such a plasma. We show that, as compared to conventional MHD for a plasma of non-relativistic particles, the hydrodynamical description of the relativistic plasma involves new degrees of freedom described by a pseudo-scalar field originating in a local asymmetry in the densities of left-handed and right-handed fermions. This field can be interpreted as an effective axion field. Taking into account the chiral anomaly we present dynamical equations for the evolution of this field, as well as of other fields appearing in the MHD description of the plasma. Due to its non-linear coupling to helical magnetic fields, the axion field significantly affects the dynamics of a magnetized plasma and can give rise to a novel type of inverse cascade.

  20. Radiation and scattering from thin wires in chiral media

    Science.gov (United States)

    Jaggard, Dwight L.; Liu, John C.; Grot, Annette; Pelet, Philippe

    1992-11-01

    The effect of chirality on thin win antennas and scatterers in unbounded chiral material is examined through the application of fundamental principles and the examination of several canonical examples. In particular, the interplay between normalized chirality and wire length is investigated to classify radiation and scattering patterns. Chirality induces rapid decay in the currents on such wires, resulting in mountain-peak-shaped current distributions characteristic of wire antennas and bow-tie-shaped current distributions characteristic of wire scatterers of sufficient length. These current distributions, in turn, cause radiation and scattering patterns which exhibit a chirality-dependent forbidden zone for both antennas and scatterers. In this zone, the fields are greatly reduced. These distinctive results lead naturally to the classification of wire scattering and radiation into subchiral, chiral, and superchiral regimes. All results are understood from the underlying physical principles of electromagnetic chirality, and are related to values of a dimensionless parameter involving normalized chirality and normalized wire length.

  1. Enantioselective catalytic syntheses of alpha-branched chiral amines

    DEFF Research Database (Denmark)

    Brase, S.; Baumann, T.; Dahmen, S.

    2007-01-01

    Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials.......Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials....

  2. A web site for calculating the degree of chirality.

    Science.gov (United States)

    Zayit, Amir; Pinsky, Mark; Elgavi, Hadassah; Dryzun, Chaim; Avnir, David

    2011-01-01

    The web site, http://www.csm.huji.ac.il/, uses the Continuous Chirality Measure to evaluate quantitatively the degree of chirality of a molecule, a structure, a fragment. The value of this measure ranges from zero, the molecule is achiral, to higher values (the upper limit is 100); the higher the chirality value, the more chiral the molecule is. The measure is based on the distance between the chiral molecule and the nearest structure that is achiral. Questions such as the following can be addressed: by how much is one molecule more chiral than the other? how does chirality change along conformational motions? is there a correlation between chirality and enantioselectivity in a series of molecules? Both elementary and advanced features are offered. Related calculation options are the symmetry measures and shape measures.

  3. Supramolecular helices: chirality transfer from conjugated molecules to structures.

    Science.gov (United States)

    Yang, Yang; Zhang, Yajie; Wei, Zhixiang

    2013-11-13

    Different scales of chirality endow a material with many excellent properties and potential applications. In this review, using π-conjugated molecules as functional building blocks, recent progress on supramolecular helices inspired by biological helicity is summarized. First, induced chirality on conjugated polymers and small molecules is introduced. Molecular chirality can be amplified to nanostructures, superstructures, and even macroscopic structures by a self-assembly process. Then, the principles for tuning the helicity of supramolecular chirality, as well as formation of helical heterojunctions, are summarized. Finally, the potential applications of chiral structures in chiral sensing and organic electronic devices are critically reviewed. Due to recent progress in chiral structures, an interdisciplinary area called "chiral electronics" is expected to gain wide popularity in the near future.

  4. Chiral heteropoly blues and controllable switching of achiral polyoxometalate clusters.

    Science.gov (United States)

    Wang, Yizhan; Li, Haolong; Wu, Che; Yang, Yang; Shi, Lei; Wu, Lixin

    2013-04-22

    Managing the blues: Chiral heteropoly blues of achiral polyoxometalate clusters were created through an intermolecular interaction with a chiral organic compound. Controllable chiroptical switching of the cluster complexes was possible through reversible photochromism of the polyoxometalates (see picture).

  5. Chiral ionic liquids in chromatographic and electrophoretic separations.

    Science.gov (United States)

    Kapnissi-Christodoulou, Constantina P; Stavrou, Ioannis J; Mavroudi, Maria C

    2014-10-10

    This report provides an overview of the application of chiral ionic liquids (CILs) in separation technology, and particularly in capillary electrophoresis and both gas and liquid chromatography. There is a large number of CILs that have been synthesized and designed as chiral agents. However, only a few have successfully been applied in separation technology. Even though this application of CILs is still in its early stages, the scientific interest is increasing dramatically. This article is focused on the use of CILs as chiral selectors, background electrolyte additives, chiral ligands and chiral stationary phases in electrophoretic and chromatographic techniques. Different examples of CILs, which contain either a chiral cation, a chiral anion or both, are presented in this review article, and their major advantages along with their potential applications in chiral electrophoretic and chromatographic recognition are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Spontaneous chiral symmetry breaking in the Tayler instability

    CERN Document Server

    Del Sordo, Fabio; Brandenburg, Axel; Mitra, Dhrubaditya

    2011-01-01

    The chiral symmetry breaking properties of the Tayler instability are discussed. Effective amplitude equations are determined in one case. This model has three free parameters that are determined numerically. Comparison with chiral symmetry breaking in biochemistry is made.

  7. METHODS DEVELOPMENT FOR THE ANALYSIS OF CHIRAL PESTICIDES

    Science.gov (United States)

    Chiral compounds exist as a pair of nonsuperimposable mirror images called enantiomers. Enantiomers have identical physical-chemical properties, but their interactions with other chiral molecules, toxicity, biodegradation, and fate are often different. Many pharmaceutical com...

  8. The Practical Asymmetric Syntheses of Key Chiral Intermediates of Chiral Drug from Four-Carbon Chiral Pool

    Institute of Scientific and Technical Information of China (English)

    MI; AiQiao

    2001-01-01

    (S)-or (R)-2-Amino-4-phenylbutyric acid and (S)-or (R)-2-hydroxy-4-phenylbutyric acid and their ethyl esters are key chiral intermediates for the preparation of angiotensin converting enzyme inhibitors (ACEI) and other chiral drugs. Their practically asymmetric synthetic methods in large scale from four-carbon chiral pool, commercially available L-aspartic acid and L-malic acid, will be presented (as scheme).  (S)-2-Amino-4-phenylbutyric acid and its ethyl ester hydrochloride were prepared from the easily available L-aspartic acid via activation by forming anhydride hydrochloride, Friedel-Crafts reaction with benzene, hydrogenolysis and esterification with ethanol in the presence of thionyl chloride in overall yield of 80% and 73.6% respectively with 99% ee. We first used amino acid anhydride hydrochloride as the acylating agent in Friedel-Crafts reaction without racemization. [1]……

  9. The Practical Asymmetric Syntheses of Key Chiral Intermediates of Chiral Drug from Four-Carbon Chiral Pool

    Institute of Scientific and Technical Information of China (English)

    MI AiQiao; LIN WenQin; HE Zhe; JIN Yi; JIANG YaoZhong

    2001-01-01

    @@ (S)-or (R)-2-Amino-4-phenylbutyric acid and (S)-or (R)-2-hydroxy-4-phenylbutyric acid and their ethyl esters are key chiral intermediates for the preparation of angiotensin converting enzyme inhibitors (ACEI) and other chiral drugs. Their practically asymmetric synthetic methods in large scale from four-carbon chiral pool, commercially available L-aspartic acid and L-malic acid, will be presented (as scheme). (S)-2-Amino-4-phenylbutyric acid and its ethyl ester hydrochloride were prepared from the easily available L-aspartic acid via activation by forming anhydride hydrochloride, Friedel-Crafts reaction with benzene, hydrogenolysis and esterification with ethanol in the presence of thionyl chloride in overall yield of 80% and 73.6% respectively with 99% ee. We first used amino acid anhydride hydrochloride as the acylating agent in Friedel-Crafts reaction without racemization. [1

  10. Optical chirality in gyrotropic media: symmetry approach

    Science.gov (United States)

    Proskurin, Igor; Ovchinnikov, Alexander S.; Nosov, Pavel; Kishine, Jun-ichiro

    2017-06-01

    We discuss optical chirality in different types of gyrotropic media. Our analysis is based on the formalism of nongeometric symmetries of Maxwell’s equations in vacuum generalized to material media with given constituent relations. This approach enables us to directly derive conservation laws related to nongeometric symmetries. For isotropic chiral media, we demonstrate that like a free electromagnetic field, both duality and helicity generators belong to the basis set of nongeometric symmetries that guarantees the conservation of optical chirality. In gyrotropic crystals, which exhibit natural optical activity, the situation is quite different from the case of isotropic media. For light propagating along a certain crystallographic direction, there arises two distinct cases: (1) the duality is broken but the helicity is preserved, or (2) only the duality symmetry survives. We show that the existence of one of these symmetries (duality or helicity) is enough to define optical chirality. In addition, we present examples of low-symmetry media, where optical chirality cannot be defined.

  11. Rotating pigment cells exhibit an intrinsic chirality.

    Science.gov (United States)

    Yamanaka, Hiroaki; Kondo, Shigeru

    2015-01-01

    In multicellular organisms, cell properties, such as shape, size and function are important in morphogenesis and physiological functions. Recently, 'cellular chirality' has attracted attention as a cellular property because it can cause asymmetry in the bodies of animals. In recent in vitro studies, the left-right bias of cellular migration and of autonomous arrangement of cells under some specific culture conditions were discovered. However, it is difficult to identify the molecular mechanism underlying their intrinsic chirality because the left-right bias observed to date is subtle or is manifested in the stable orientation of cells. Here, we report that zebrafish (Danio rerio) melanophores exhibit clear cellular chirality by unidirectional counterclockwise rotational movement under isolated conditions without any special settings. The chirality is intrinsic to melanophores because the direction of the cellular rotation was not affected by the type of extracellular matrix. We further found that the cellular rotation was generated as a counter action of the clockwise movement of actin cytoskeleton. It suggested that the mechanism that directs actin cytoskeleton in the clockwise direction is pivotal for determining cellular chirality.

  12. [Preparations and biological properties of chiral compounds].

    Science.gov (United States)

    Sinko, Goran

    2005-12-01

    Enantiomers of chiral compounds may express various biological activities and also different toxicities. Examples of different pharmacological effects of some chiral drugs such as fluoxetine, penicillamine, ibuprofen and albuterol are provided in this paper. Due to possible differences in activity, the chiral drugs are required to be pure enantiomeric compounds in order to be more effective and safer to use. In the laboratory, enantiomers are mainly synthesized as racemates (an equimolar mixture of enantiomers) while in biological pathways only one enantiomeric form is produced, such as amino acids, sugars and lipids. This paper presents the principles of chirality, general information about enantiomers and their biological aspects. It gives an outline of stereoselective methods for chromatographic resolution of enantiomers with stereoselective protein stationary phases, i.e. capillary electrochromatography (CEC) and high performance liquid chromatography (HPLC). The use of enzyme biotransformations (hydrolysis, oxidation and reduction) in chiral syntheses of carboxyl-, phosphoryl- or beta-hydroxy esters, alcohols, epoxides and cis-carboxyl sulphoxide is described. This article also includes an example of lipase stereoselectivity improvement by amino acid mutations within the enzyme active site.

  13. Helical Ordering in Chiral Block Copolymers

    Science.gov (United States)

    Zhao, Wei; Hong, Sung Woo; Chen, Dian; Grason, Gregory; Russell, Thomas

    2012-02-01

    Introducing molecular chirality into the segments of block copolymers can influence the nature of the resultant morphology. Such an effect was found for poly(styrene-b-L-lactide) (PS-b-PLLA) diblock copolymers where hexagonally packed PLLA helical microdomains (H* phase) form in a PS matrix. However, molecular ordering of PLLA within the helical microdomains and the transfer of chirality from the segmental level to the mesoscale is still not well understood. We developed a field theoretic model to describe the interactions between segments of chiral blocks, which have the tendency to form a ``cholesteric'' texture. Based on the model, we calculated the bulk morphologies of chiral AB diblock copolymers using self-consistent field theory (SCFT). Experiments show that the H* phase only forms when microphase separation between PS and PLLA block happens first and crystallization of PLLA block is suppressed or happens within confined microdomain. Hence, crystalline ordering is not necessary for H* phase formation. The SCFT offers the chance to explore the range of thermodynamic stability of helical structures in the phase diagram of chiral block copolymer melts, by tuning parameters not only like the block segregation strength and composition, but also new parameters such as the ratio between preferred helical pitch to the radius of gyration and the Frank elastic constant for inter-segment distortions.

  14. On the chiral imbalance and Weibel instabilities

    Science.gov (United States)

    Kumar, Avdhesh; Bhatt, Jitesh R.; Kaw, P. K.

    2016-06-01

    We study the chiral-imbalance and the Weibel instabilities in presence of the quantum anomaly using the Berry-curvature modified kinetic equation. We argue that in many realistic situations, e.g. relativistic heavy-ion collisions, both the instabilities can occur simultaneously. The Weibel instability depends on the momentum anisotropy parameter ξ and the angle (θn) between the propagation vector and the anisotropy direction. It has maximum growth rate at θn = 0 while θn = π / 2 corresponds to a damping. On the other hand the pure chiral-imbalance instability occurs in an isotropic plasma and depends on difference between the chiral chemical potentials of right and left-handed particles. It is shown that when θn = 0, only for a very small values of the anisotropic parameter ξ ∼ξc, growth rates of the both instabilities are comparable. For the cases ξc Weibel modes dominate over the chiral-imbalance instability if μ5 / T ≤ 1. However, when μ5 / T ≥ 1, it is possible to have dominance of the chiral-imbalance modes at certain values of θn for an arbitrary ξ.

  15. Chiral effects in the confining QCD vacuum

    CERN Document Server

    Simonov, Yu A

    1994-01-01

    Configurations are introduced into the standard instanton vacuum model. This drastically improves theoretical properties of the vacuum: instanton size density $d(\\rho)$ stabilizes at $\\rho\\sim 0.2 fm$, all chiral effects are formulated in a gauge-invariant way and quarks are confined. An interesting interplay of chiral and confining dynamics is observed; for the realistic values of parameters the Georgi-Manohar picture emerges with chiral radius $R_{ch}\\sim \\rho\\sim 0.2 fm$ much less than confining radius $R_c\\sim$ hadron radius $\\sim 1 fm$. In the limit $R_{ch}\\ll R_c$ the chiral mass $M_{ch}(p)$ is unaffected by confinement and can be taken in the local limit $M_{ch}(p=0)$. Different types of effective chiral Lagrangians (ECL) are obtained, containing all or a part of gluon, quark and Nambu--Goldstone--meson fields. The ECL are manifestly gauge--invariant and in the limit of no gluon fields coincide with those found previously. The problem of the double role of the pion -- as a Goldstone meson or as a $q\\ba...

  16. Inhomogeneous Polyakov loop induced by inhomogeneous chiral condensates

    Directory of Open Access Journals (Sweden)

    Tomoya Hayata

    2015-05-01

    Full Text Available We study the spatial inhomogeneity of the Polyakov loop induced by inhomogeneous chiral condensates. We formulate an effective model of gluons on the background fields of chiral condensates, and perform its lattice simulation. On the background of inhomogeneous chiral condensates, the Polyakov loop exhibits an in-phase spatial oscillation with the chiral condensates. We also analyze the heavy quark potential and show that the inhomogeneous Polyakov loop indicates the inhomogeneous confinement of heavy quarks.

  17. Inhomogeneous Polyakov loop induced by inhomogeneous chiral condensates

    Energy Technology Data Exchange (ETDEWEB)

    Hayata, Tomoya, E-mail: hayata@riken.jp [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Yamamoto, Arata [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2015-05-11

    We study the spatial inhomogeneity of the Polyakov loop induced by inhomogeneous chiral condensates. We formulate an effective model of gluons on the background fields of chiral condensates, and perform its lattice simulation. On the background of inhomogeneous chiral condensates, the Polyakov loop exhibits an in-phase spatial oscillation with the chiral condensates. We also analyze the heavy quark potential and show that the inhomogeneous Polyakov loop indicates the inhomogeneous confinement of heavy quarks.

  18. New Terms for Compact Form of Electroweak Chiral Lagrangian

    Institute of Scientific and Technical Information of China (English)

    YE Wei; ZHANG Hong-Hao; YANG Hong-Wei; YAN Wen-Bin; CHEN Na; J.K. Parry; LI Xue-Song

    2008-01-01

    The compact form of the electroweak chiral Lagrangian is a reformulation of its original form and is expressed in terms of chiral rotated electroweak gauge fields, which is crucial for relating the information of underlying theories to the coefficients of the low-energy effective Lagrangian. However the compact form obtained in previous works is not complete. In this letter we add several new chiral invariant terms to it and discuss the contributions of these terms to the original electroweak chiral Lagrangian.

  19. Novel Lifshitz point for chiral transition in the magnetic field

    Directory of Open Access Journals (Sweden)

    Toshitaka Tatsumi

    2015-04-01

    Full Text Available Based on the generalized Ginzburg–Landau theory, chiral phase transition is discussed in the presence of magnetic field. Considering the chiral density wave we show that chiral anomaly gives rise to an inhomogeneous chiral phase for nonzero quark-number chemical potential. Novel Lifshitz point appears on the vanishing chemical potential line, which may be directly explored by the lattice QCD simulation.

  20. Emerging functional chiral microporous materials: synthetic strategies and enantioselective separations

    Directory of Open Access Journals (Sweden)

    Ming Xue

    2016-11-01

    Full Text Available In recent years, chiral microporous materials with open pores have attracted much attention because of their potential applications in enantioselective separation and catalysis. This review summarizes the recent advances on chiral microporous materials, such as metal-organic frameworks (MOFs, hydrogen-bonded organic frameworks (HOFs and covalent organic frameworks (COFs. We will introduce the synthetic strategies in detail and highlight the current status of chiral microporous materials on solid enantioselective adsorption, chiral chromatography resolution and membrane separation.

  1. Acylation of Chiral Alcohols: A Simple Procedure for Chiral GC Analysis

    Directory of Open Access Journals (Sweden)

    Mireia Oromí-Farrús

    2012-01-01

    Full Text Available The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was studied. Although no isomerization was observed when acetic acid was used, partial isomerization was detected with the trifluoroacetic acid. A series of chiral alcohols of a widely varying structural type were then derivatized with acetic acid using the optimal conditions. The resolution of the enantiomeric esters and the free chiral alcohols was measured using a capillary gas chromatograph equipped with a CP Chirasil-DEX CB column. The best resolutions were obtained with 2-pentyl acetates (α=3.00 and 2-hexyl acetates (α=1.95. This method provides a very simple and efficient experimental workup procedure for analyzing chiral alcohols by chiral-phase GC.

  2. Influence of Axial and Point Chirality in the Chiral Self-Assembly of Twin N-Annulated Perylenecarboxamides.

    Science.gov (United States)

    Buendía, Julia; Greciano, Elisa E; Sánchez, Luis

    2015-12-18

    The synthesis of three bis(N-annulated perylenecarboxamides) endowed with achiral or chiral side chains is reported. The restricted rotation of the perylene moieties yields atropisomers that can be separated by chiral HPLC. The CD spectra of the six stereoisomers show a dichroic pattern in a good solvent that changes drastically upon adding a poor solvent that favors the aggregation. The cooperative character of the supramolecular polymerization mechanism of 1-3 has been determined by denaturation experiments, which reveal that the formation of homochiral aggregates is favored over the formation of heterochiral aggregates. A complete set of amplification of chirality experiments have been carried out, revealing the preponderance of axial chirality over point chirality. The results presented herein shed relevant light on the structural conditions exhibited by molecular units endowed with different elements of asymmetry to generate chiral supramolecular structures and the supremacy of axial chirality over point chirality in the origin of homochirality.

  3. Chiral doublet bands and energy-level crossing

    Institute of Scientific and Technical Information of China (English)

    QI Bin; MENG Jie; ZHANG Shuang-Quan; WANG Shou-Yu; PENG Jing

    2009-01-01

    Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the electromagnetic transitions in different band definitions are illustrated. It is also shown that the energy-level crossings between chiral doublet bands may occur.

  4. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG XiaoMing

    2001-01-01

    @@ Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.

  5. Meson Effects on the Chiral Condensate at Finite Density

    Institute of Scientific and Technical Information of China (English)

    HUANG Mei; ZHUANG Peng-Fei; ZHAO Wei-Qin

    2002-01-01

    Meson corrections on the chiral condensate up to next-to-leading order in a 1/Nc expansion at finite densityare investigated in the NJL model with explicit chiral symmetry breaking. Compared with mean-field results, the chiralphase transition is still of the first order while the properties near the critical density for chiral phase transition are foundto change significantly.

  6. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG; XiaoMing

    2001-01-01

    Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.  ……

  7. Invariant Regularization of Supersymmetric Chiral Gauge Theory

    CERN Document Server

    Hayashi, T; Okuyama, K; Suzuki, H; Hayashi, Takuya; Ohshima, Yoshihisa; Okuyama, Kiyoshi; Suzuki, Hiroshi

    1998-01-01

    We formulate a manifestly supersymmetric gauge-covariant regularization of supersymmetric chiral gauge theories. In our scheme, the effective action in the superfield background-field method above one-loop is always supersymmetric and gauge invariant. The gauge anomaly has the covariant form and can emerge only in one-loop diagrams with all the external lines are the background gauge superfield. We also present several illustrative applications in the one-loop approximation: The self-energy part of the chiral multiplet and the gauge multiplet; the super-chiral anomaly and the superconformal anomaly; as the corresponding anomalous commutators, the Konishi anomaly and the anomalous supersymmetric transformation law of the supercurrent (the ``central extension'' of N=1 supersymmetry algebra) and of the R-current.

  8. Energy Conservation and the Chiral Magnetic Effect

    CERN Document Server

    Kaplan, David B; Sen, Srimoyee

    2016-01-01

    We analyze the chiral magnetic effect in a neutral plasma from the point of view of energy conservation, and construct an effective potential for the growth of helical perturbations of the electromagnetic field. We show that a negative curvature at the origin of the potential, indicating instability of the plasma, is induced by a chiral asymmetry in electron Fermi energy, as opposed to number density, while the potential grows at large field value. It follows that the ground state for a plasma has zero magnetic helicity; a nonzero electron mass will allow an excited state of a plasma with nonzero helicity to relax to that ground state quickly. We conclude that a chiral plasma instability triggered by weak interactions is not a viable mechanism for explaining magnetic fields in neutron stars.

  9. Vector solitons in nonlinear isotropic chiral metamaterials

    CERN Document Server

    Tsitsas, N L; Frantzeskakis, D J

    2011-01-01

    Starting from the Maxwell equations, we used the reductive perturbation method to derive a system of two coupled nonlinear Schr\\"{o}dinger (NLS) equations for the two Beltrami components of the electromagnetic field propagating along a fixed direction in an isotropic nonlinear chiral metamaterial. With single-resonance Lorentz models for the permittivity and permeability and a Condon model for the chirality parameter, in certain spectral regimes, one of the two Beltrami components exhibits a negative real refractive index when nonlinearity is ignored and the chirality parameter is sufficiently large.We found that, inside such a spectral regime, there may exist a subregime wherein the system of the NLS equations can be approximated by the Manakov system. Bright-bright, dark-dark, and dark-bright vector solitons can be formed in that spectral subregime.

  10. Analysis of chiral symmetry breaking mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Xin-Heng, Guo [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Tao, Huang [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics; Chuang, Wang

    1997-07-01

    The renormalization group invariant quark condensate {mu} is determinate both from the consistent equation for quark condensate in the chiral limit and from the Schwinger-Dyson (SD) equation improved by the intermediate range QCD force singular like {delta} (q) which is associated with the gluon condensate. The solutions of {mu} in these two equations are consistent. We also obtain the critical strong coupling constant {alpha}c above which chiral symmetry breaks in two approaches. The nonperturbative kernel of the SD equation makes {alpha}c smaller and {mu} bigger. An intuitive picture of the condensation above {alpha}c is discussed. In addition, with the help of the Slavnov-Taylor-Ward (STW) identity we derive the equations for the nonperturbative quark propagator from SD equation in the presence of the intermediate-range force is also responsible for dynamical chiral symmetry breaking. (author) 32 refs., 2 figs.

  11. Chiral light by symmetric optical antennas

    CERN Document Server

    Mekonnen, Addis; Zubritskaya, Irina; Jönsson, Gustav Edman; Dmitriev, Alexandre

    2014-01-01

    Chirality is at the origin of life and is ubiquitous in nature. An object is deemed chiral if it is non-superimposable with its own mirror image. This relates to how circularly polarized light interacts with such object, a circular dichroism, the differential absorption of right and left circularly polarized light. According to the common understanding in biology, chemistry and physics, the circular dichroism results from an internal chiral structure or external symmetry breaking by illumination. We show that circular dichroism is possible with simple symmetric optical nanoantennas at symmetric illumination. We experimentally and theoretically demonstrate that two electromagnetic dipole-like modes with a phase lag, in principle, suffice to produce circular dichroism in achiral structure. Examples of the latter are all visible spectrum optical nanoantennas, symmetric nanoellipses and nanodimers. The simplicity and generality of this finding reveal a whole new significance of the electromagnetic design at a nan...

  12. Gluonic Lorentz violation and chiral perturbation theory

    Science.gov (United States)

    Noordmans, J. P.

    2017-04-01

    By applying chiral-perturbation-theory methods to the QCD sector of the Lorentz-violating Standard-Model Extension, we investigate Lorentz violation in the strong interactions. In particular, we consider the C P T -even pure-gluon operator of the minimal Standard-Model Extension. We construct the lowest-order chiral effective Lagrangian for three as well as two light quark flavors. We develop the power-counting rules and construct the heavy-baryon chiral-perturbation-theory Lagrangian, which we use to calculate Lorentz-violating contributions to the nucleon self-energy. Using the constructed effective operators, we derive the first stringent limits on many of the components of the relevant Lorentz-violating parameter. We also obtain the Lorentz-violating nucleon-nucleon potential. We suggest that this potential may be used to obtain new limits from atomic-clock or deuteron storage-ring experiments.

  13. Chiral bosonization for non-commutative fields

    CERN Document Server

    Das, A; Méndez, F; López-Sarrion, J; Das, Ashok; Gamboa, Jorge; M\\'endez, Fernando; L\\'opez-Sarri\\'on, Justo

    2004-01-01

    A model of chiral bosons on a non-commutative field space is constructed and new generalized bosonization (fermionization) rules for these fields are given. The conformal structure of the theory is characterized by a level of the Kac-Moody algebra equal to $(1+ \\theta^2)$ where $\\theta$ is the non-commutativity parameter and chiral bosons living in a non-commutative fields space are described by a rational conformal field theory with the central charge of the Virasoro algebra equal to 1. The non-commutative chiral bosons are shown to correspond to a free fermion moving with a speed equal to $ c^{\\prime} = c \\sqrt{1+\\theta^2} $ where $c$ is the speed of light. Lorentz invariance remains intact if $c$ is rescaled by $c \\to c^{\\prime}$. The dispersion relation for bosons and fermions, in this case, is given by $\\omega = c^{\\prime} | k|$.

  14. Synthesis of chiral dopants based on carbohydrates.

    Science.gov (United States)

    Tsuruta, Toru; Koyama, Tetsuo; Yasutake, Mikio; Hatano, Ken; Matsuoka, Koji

    2014-07-01

    Chiral dopants based on carbohydrates for nematic liquid crystals were synthesized from D-glucose, and their helical twisting power (HTP) values were evaluated. The chiral dopants induced helices in the host nematic liquid crystals. An acetyl derivative having an ether-type glycosidic linkage between carbohydrate and a mesogenic moiety showed the highest HTP value of 10.4 μm(-1), while an acetyl derivative having an anomeric ester-type linkage did not show any HTP. It was surprising that this molecule had no HTP despite the presence of chirality in the molecule. A relationship between HTP and specific rotation was not observed in this study. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Chiral Perturbation Theory With Lattice Regularization

    CERN Document Server

    Ouimet, P P A

    2005-01-01

    In this work, alternative methods to regularize chiral perturbation theory are discussed. First, Long Distance Regularization will be considered in the presence of the decuplet of the lightest spin 32 baryons for several different observables. This serves motivation and introduction to the use of the lattice regulator for chiral perturbation theory. The mesonic, baryonic and anomalous sectors of chiral perturbation theory will be formulated on a lattice of space time points. The consistency of the lattice as a regulator will be discussed in the context of the meson and baryon masses. Order a effects will also be discussed for the baryon masses, sigma terms and magnetic moments. The work will close with an attempt to derive an effective Wess-Zumino-Witten Lagrangian for Wilson fermions at non-zero a. Following this discussion, there will be a proposal for a phenomenologically useful WZW Lagrangian at non-zero a.

  16. Chiral scars in chaotic Dirac fermion systems.

    Science.gov (United States)

    Xu, Hongya; Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso

    2013-02-08

    Do relativistic quantum scars in classically chaotic systems possess unique features that are not shared by nonrelativistic quantum scars? We report a class of relativistic quantum scars in massless Dirac fermion systems whose phases return to the original values or acquire a 2π change only after circulating twice about some classical unstable periodic orbits. We name such scars chiral scars, the successful identification of which has been facilitated tremendously by our development of an analytic, conformal-mapping-based method to calculate an unprecedentedly large number of eigenstates with high accuracy. Our semiclassical theory indicates that the physical origin of chiral scars can be attributed to a combined effect of chirality intrinsic to massless Dirac fermions and the geometry of the underlying classical orbit.

  17. Hydrodynamics of the Chiral Dirac Spectrum

    CERN Document Server

    Liu, Yizhuang; Zahed, Ismail

    2016-01-01

    We derive a hydrodynamical description of the eigenvalues of the chiral Dirac spectrum in the vacuum and in the large $N$ (volume) limit. The linearized hydrodynamics supports sound waves. The stochastic relaxation of the eigenvalues is captured by a hydrodynamical instanton configuration which follows from a pertinent form of Euler equation. The relaxation from a phase of localized eigenvalues and unbroken chiral symmetry to a phase of de-localized eigenvalues and broken chiral symmetry occurs over a time set by the speed of sound. We show that the time is $\\Delta \\tau=\\pi\\rho(0)/2\\beta N$ with $\\rho(0)$ the spectral density at zero virtuality and $\\beta=1,2,4$ for the three Dyson ensembles that characterize QCD with different quark representations in the ergodic regime.

  18. Viscoelastic modes in chiral liquid crystals

    Indian Academy of Sciences (India)

    K A Suresh

    2003-08-01

    Viscoelastic properties of liquid crystals are very important for applications like display technology. However, there are not many direct techniques to study them. In this review, we describe our studies on the viscoelastic modes of some chiral liquid crystals using dynamic light scattering. We discuss viscoelastic modes corresponding to the C director fluctuations in the chiral smectic C phase and the behaviour of the Goldstone-mode near the chiral smectic C–smectic A phase transition. In cholesteric liquid crystals, we consider the director fluctuations in a wavevector range comparable to the inverse pitch of the cholesteric. Here, the study of the scattered light in the vicinity of the Bragg reflection using a novel geometry will be presented.

  19. Interference Phenomenon for Different Chiral Bosonization Schemes

    CERN Document Server

    Abreu, Everton M C; Abreu, Everton M C; Wotzasek, Clovis

    1998-01-01

    We study the relationship between different chiral bosonization schemes (CBS) in the context of the soldering formalism\\cite{MS}, that considers the phenomenon of interference in the quantum field theory\\cite{ABW}. This analysis is done in the framework put forward by Siegel\\cite{WS} and by Floreanini and Jackiw\\cite{FJ} (FJ). We propose a field redefinition that discloses the presence of a noton, a non dynamical field, in Siegel's formulation for chiral bosons. The presence of a noton in the Siegel CBS is a new and surprising result, that separates dynamics from symmetry by diagonalising the Siegel action into the FJ and the noton action. While the first describes the chiral dynamics, the noton carries the symmetry contents, acquiring dynamics upon quantization and is fully responsible for the Siegel anomaly. The diagonal representation proposed here is used to study the effect of quantum interference between gauged rightons and leftons.

  20. Chiral specific electron vortex beam spectroscopy

    CERN Document Server

    Yuan, J; Babiker, M

    2013-01-01

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  1. Vector solitons in nonlinear isotropic chiral metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Tsitsas, N L [School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografos, Athens 15773 (Greece); Lakhtakia, A [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States); Frantzeskakis, D J, E-mail: dfrantz@phys.uoa.gr [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece)

    2011-10-28

    Starting from the Maxwell equations, we used the reductive perturbation method to derive a system of two coupled nonlinear Schroedinger (NLS) equations for the two Beltrami components of the electromagnetic field propagating along a fixed direction in an isotropic nonlinear chiral metamaterial. With single-resonance Lorentz models for the permittivity and permeability and a Condon model for the chirality parameter, in certain spectral regimes, one of the two Beltrami components exhibits a negative-real refractive index when nonlinearity is ignored and the chirality parameter is sufficiently large. We found that, inside such a spectral regime, there may exist a subregime wherein the system of the NLS equations can be approximated by the Manakov system. Bright-bright, dark-dark, and dark-bright vector solitons can be formed in that spectral subregime. (paper)

  2. Chirally symmetric strong and electroweak interactions

    Science.gov (United States)

    Rajpoot, Subhash

    1988-07-01

    Strong and electroweak interactions may be a relic of the spontaneous breakdown of a chirally symmetric colour-flavour gauge group. The minimum possibility of such a structure that is symmetric between left and right is SU(3) L×SU(3) R×SU(2) L×SU(2) R×U(1) B- L where quantum chromodynamics originates in the chiral colour group SU(3) L×SU(3) R and the electroweak interaction originates in the ambidextrous electroweak interaction group SU L×SU(2) R×U(1) B- L. The chiral anomalies are cancelled by adding a set of fermions that transform as singlets under the weak interaction group SU(2) L×SU(2) R. This model requires only three Higgs representations to break the proposed gauge symmetry to SU(3) C×U(1) em and give masses to all the quarks and leptons of the theory. All fermion masses are “see-saw” masses.

  3. Chiral Liquid Crystals: Structures, Phases, Effects

    Directory of Open Access Journals (Sweden)

    Ingo Dierking

    2014-06-01

    Full Text Available The introduction of chirality, i.e., the lack of mirror symmetry, has a profound effect on liquid crystals, not only on the molecular scale but also on the supermolecular scale and phase. I review these effects, which are related to the formation of supermolecular helicity, the occurrence of novel thermodynamic phases, as well as electro-optic effects which can only be observed in chiral liquid crystalline materials. In particular, I will discuss the formation of helical superstructures in cholesteric, Twist Grain Boundary and ferroelectric phases. As examples for the occurrence of novel phases the Blue Phases and Twist Grain Boundary phases are introduced. Chirality related effects are demonstrated through the occurrence of ferroelectricity in both thermotropic as well as lyotropic liquid crystals. Lack of mirror symmetry is also discussed briefly for some biopolymers such as cellulose and DNA, together with its influence on liquid crystalline behavior.

  4. Chiral Molecules Revisited by Broadband Microwave Spectroscopy

    Science.gov (United States)

    Schnell, Melanie

    2014-06-01

    Chiral molecules have fascinated chemists for more than 150 years. While their physical properties are to a very good approximation identical, the two enantiomers of a chiral molecule can have completely different (bio)chemical activities. For example, the right-handed enantiomer of carvone smells of spearmint while the left-handed one smells of caraway. In addition, the active components of many drugs are of one specific handedness, such as in the case of ibuprofen. However, in nature as well as in pharmaceutical applications, chiral molecules often exist in mixtures with other chiral molecules. The analysis of these complex mixtures to identify the molecular components, to determine which enantiomers are present, and to measure the enantiomeric excesses (ee) remains a challenging task for analytical chemistry, despite its importance for modern drug development. We present here a new method of differentiating enantiomers of chiral molecules in the gas phase based on broadband rotational spectroscopy. The phase of the acquired signal bares the signature of the enantiomer, as it depends upon the combined quantity, μ_a μ_b μ_c, which is of opposite sign between enantiomers. It thus also provides information on the absolute configuration of the particular enantiomer. Furthermore, the signal amplitude is proportional to the ee. A significant advantage of our technique is its inherent mixture compatibility due to the fingerprint-like character of rotational spectra. In this contribution, we will introduce the technique and present our latest results on chiral molecule spectroscopy and enantiomer differentiation. D. Patterson, M. Schnell, J.M. Doyle, Nature 497 (2013) 475-477 V.A. Shubert, D. Schmitz, D. Patterson, J.M. Doyle, M. Schnell, Angewandte Chemie International Edition 53 (2014) 1152-1155

  5. Revealing atropisomer axial chirality in drug discovery.

    Science.gov (United States)

    LaPlante, Steven R; Edwards, Paul J; Fader, Lee D; Jakalian, Araz; Hucke, Oliver

    2011-03-07

    An often overlooked source of chirality is atropisomerism, which results from slow rotation along a bond axis due to steric hindrance and/or electronic factors. If undetected or not managed properly, this time-dependent chirality has the potential to lead to serious consequences, because atropisomers can be present as distinct enantiomers or diastereoisomers with their attendant different properties. Herein we introduce a strategy to reveal and classify compounds that have atropisomeric chirality. Energy barriers to axial rotation were calculated using quantum mechanics, from which predicted high barriers could be experimentally validated. A calculated rotational energy barrier of 20 kcal mol(-1) was established as a suitable threshold to distinguish between atropisomers and non-atropisomers with a prediction accuracy of 86%. This methodology was applied to subsets of drug databases in the course of which atropisomeric drugs were identified. In addition, some drugs were exposed that were not yet known to have this chiral attribute. The most valuable utility of this tool will be to predict atropisomerism along the drug discovery pathway. When used in concert with our compound classification scheme, decisions can be made during early discovery stages such as "hit-to-lead" and "lead optimization," to foresee and validate the presence of atropisomers and to exercise options of removing, further stabilizing, or rendering the chiral axis of interest more freely rotatable via SAR design, thereby decreasing this potential liability within a compound series. The strategy can also improve drug development plans, such as determining whether a drug or series should be developed as a racemic mixture or as an isolated single compound. Moreover, the work described herein can be extended to other chemical fields that require the assessment of potential chiral axes.

  6. Invariant Regularization of Supersymmetric Chiral Gauge Theory

    CERN Document Server

    Suzuki, H

    1999-01-01

    We present a regularization scheme which respects the supersymmetry and the maximal background gauge covariance in supersymmetric chiral gauge theories. When the anomaly cancellation condition is satisfied, the effective action in the superfield background field method automatically restores the gauge invariance without counterterms. The scheme also provides a background gauge covariant definition of composite operators that is especially useful in analyzing anomalies. We present several applications: The minimal consistent gauge anomaly; the super-chiral anomaly and the superconformal anomaly; as the corresponding anomalous commutators, the Konishi anomaly and an anomalous supersymmetric transformation law of the supercurrent (the ``central extension'' of N=1 supersymmetry algebra) and of the R-current.

  7. Chiral Surface Waves for Enhanced Circular Dichroism

    CERN Document Server

    Pellegrini, Giovanni; Celebrano, Michele; Duò, Lamberto; Biagioni, Paolo

    2016-01-01

    We present a novel chiral sensing platform that combines a one-dimensional photonic crystal design with a birefringent surface defect. The platform sustains simultaneous transverse electric and transverse magnetic surface modes, which are exploited to generate chiral surface waves. The present design provides homogeneous and superchiral fields of both handednesses over arbitrarily large areas in a wide spectral range, resulting in the enhancement of the circular dichroism signal by two orders of magnitude, thus paving the road toward the successful combination of surface-enhanced spectroscopies and electromagnetic superchirality.

  8. Pentaquarks in chiral color dielectric model

    Indian Academy of Sciences (India)

    S C Pathak

    2006-04-01

    Recent experiments indicate that a narrow baryonic state having strangeness +1 and mass of about 1540 MeV may be existing. Such a state was predicted in chiral model by Diakonov et al. In this work I compute the mass and width of this state in chiral color dielectric model. I show that the computed width is about 30 MeV. I find that the mass of the state can be fitted to the experimentally observed mass by invoking a color neutral vector field and its interaction with the quarks.

  9. Probing Chiral Interactions in Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P

    2004-01-08

    Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.

  10. Dynamics of the chiral phase transition

    CERN Document Server

    van Hees, H; Meistrenko, A; Greiner, C

    2013-01-01

    The intention of this study is the search for signatures of the chiral phase transition in heavy-ion collisions. To investigate the impact of fluctuations, e.g., of the baryon number, at the transition or at a critical point, the linear sigma model is treated in a dynamical (3+1)-dimensional numerical simulation. Chiral fields are approximated as classical mean fields, and quarks are described as quasi particles in a Vlasov equation. Additional dynamics is implemented by quark-quark and quark-sigma-field interactions. For a consistent description of field-particle interactions, a new Monte-Carlo-Langevin-like formalism has been developed and is discussed.

  11. Chirality effects on 2D phase transitions

    DEFF Research Database (Denmark)

    Scalas, E.; Brezesinski, G.; Möhwald, H.

    1996-01-01

    -nearest neighbours (NNN) and an NNN-distorted lattice is observed. At 5 degrees C, the transition pressure is 15 mN m(-1), whereas at 20 degrees C it is 18 mN m(-1). Chirality destroys this transition: the pure enantiomer always exhibits an oblique lattice with tilted molecules, and the azimuths of tilt...... and distortion continuously vary from a direction close to NN to a direction close to NNN. The nature of the phase transition and the influence of chirality on it are discussed within the framework of Landau's theory of phase transitions....

  12. Chiral logarithms in the massless limit tamed.

    Science.gov (United States)

    Kivel, Nikolai; Polyakov, Maxim V; Vladimirov, Alexei

    2008-12-31

    We derive nonlinear recursion relations for the leading chiral logarithms (LLs) in massless theories. These relations not only provide a very efficient method of computation of LLs (e.g., the 33-loop contribution is calculated in a dozen of seconds on a PC) but also equip us with a powerful tool for the summation of the LLs. Our method is not limited to chiral perturbation theory only; it is pertinent to any nonrenormalizable effective field theory such as, for instance, the theory of critical phenomena, low-energy quantum gravity, etc.

  13. Phenomenology of chiral damping in noncentrosymmetric magnets

    KAUST Repository

    Akosa, Collins Ashu

    2016-06-21

    A phenomenology of magnetic chiral damping is proposed in the context of magnetic materials lacking inversion symmetry. We show that the magnetic damping tensor acquires a component linear in magnetization gradient in the form of Lifshitz invariants. We propose different microscopic mechanisms that can produce such a damping in ferromagnetic metals, among which local spin pumping in the presence of an anomalous Hall effect and an effective “s-d” Dzyaloshinskii-Moriya antisymmetric exchange. The implication of this chiral damping in terms of domain-wall motion is investigated in the flow and creep regimes.

  14. Vector Meson Masses in Chiral Perturbation Theory

    CERN Document Server

    Bijnens, J; Talavera, P

    1997-01-01

    We discuss the vector meson masses within the context of Chiral Perturbation Theory performing an expansion in terms of the momenta, quark masses and 1/Nc. We extend the previous analysis to include isospin breaking effects and also include up to order p^4. We discuss vector meson chiral perturbation theory in some detail and present a derivation from a relativistic lagrangian. The unknown coefficients are estimated in various ways. We also discuss the relevance of electromagnetic corrections and the implications of the present calculation for the determination of quark masses.

  15. Chirality sensing with stereodynamic biphenolate zinc complexes.

    Science.gov (United States)

    Bentley, Keith W; de Los Santos, Zeus A; Weiss, Mary J; Wolf, Christian

    2015-10-01

    Two bidentate ligands consisting of a fluxional polyarylacetylene framework with terminal phenol groups were synthesized. Reaction with diethylzinc gives stereodynamic complexes that undergo distinct asymmetric transformation of the first kind upon binding of chiral amines and amino alcohols. The substrate-to-ligand chirality imprinting at the zinc coordination sphere results in characteristic circular dichroism signals that can be used for direct enantiomeric excess (ee) analysis. This chemosensing approach bears potential for high-throughput ee screening with small sample amounts and reduced solvent waste compared to traditional high-performance liquid chromatography methods.

  16. Heavy-tailed chiral random matrix theory

    CERN Document Server

    Kanazawa, Takuya

    2016-01-01

    We study an unconventional chiral random matrix model with a heavy-tailed probabilistic weight. The model is shown to exhibit chiral symmetry breaking with no bilinear condensate, in analogy to the Stern phase of QCD. We solve the model analytically and obtain the microscopic spectral density and the smallest eigenvalue distribution for an arbitrary number of flavors and arbitrary quark masses. Exotic behaviors such as non-decoupling of heavy flavors and a power-law tail of the smallest eigenvalue distribution are illustrated.

  17. Chiral surface waves for enhanced circular dichroism

    Science.gov (United States)

    Pellegrini, Giovanni; Finazzi, Marco; Celebrano, Michele; Duò, Lamberto; Biagioni, Paolo

    2017-06-01

    We present a novel chiral sensing platform that combines a one-dimensional photonic crystal design with a birefringent surface defect. The platform sustains simultaneous transverse electric and transverse magnetic surface modes, which are exploited to generate chiral surface waves. The present design provides homogeneous and superchiral fields of both handednesses over arbitrarily large areas in a wide spectral range, resulting in the enhancement of the circular dichroism signal by more than two orders of magnitude, thus paving the road toward the successful combination of surface-enhanced spectroscopies and electromagnetic superchirality.

  18. Heavy-tailed chiral random matrix theory

    Science.gov (United States)

    Kanazawa, Takuya

    2016-05-01

    We study an unconventional chiral random matrix model with a heavy-tailed probabilistic weight. The model is shown to exhibit chiral symmetry breaking with no bilinear condensate, in analogy to the Stern phase of QCD. We solve the model analytically and obtain the microscopic spectral density and the smallest eigenvalue distribution for an arbitrary number of flavors and arbitrary quark masses. Exotic behaviors such as non-decoupling of heavy flavors and a power-law tail of the smallest eigenvalue distribution are illustrated.

  19. Rotating optical microcavities with broken chiral symmetry

    CERN Document Server

    Sarma, Raktim; Wiersig, Jan; Cao, Hui

    2014-01-01

    We demonstrate in open microcavities with broken chiral symmetry, quasi-degenerate pairs of co-propagating modes in a non-rotating cavity evolve to counter-propagating modes with rotation. The emission patterns change dramatically by rotation, due to distinct output directions of CW and CCW waves. By tuning the degree of spatial chirality, we maximize the sensitivity of microcavity emission to rotation. The rotation-induced change of emission is orders of magnitude larger than the Sagnac effect, pointing to a promising direction for ultrasmall optical gyroscopes.

  20. Chiral pesticides: Identification, description, and environmental implications

    Science.gov (United States)

    Ulrich, Elin M.; Morrison, Candice N.; Goldsmith, Michael R.; Foreman, William T.

    2012-01-01

    Anthropogenic chemicals, including pesticides, are a major source of contamination and pollution in the environment. Pesticides have many positive uses: increased food production, decreased damage to crops and structures, reduced disease vector populations, and more. Nevertheless, pesticide exposure can pose risks to humans and the environment, so various mitigation strategies are exercised to make them safer, minimize their use, and reduce their unintended environment effects. One strategy that may help achieve these goals relies on the unique properties of chirality or molecular asymmetry. Some common terms related to chirality are defined in Table 1.

  1. Speciation and gene flow between snails of opposite chirality.

    Directory of Open Access Journals (Sweden)

    Angus Davison

    2005-09-01

    Full Text Available Left-right asymmetry in snails is intriguing because individuals of opposite chirality are either unable to mate or can only mate with difficulty, so could be reproductively isolated from each other. We have therefore investigated chiral evolution in the Japanese land snail genus Euhadra to understand whether changes in chirality have promoted speciation. In particular, we aimed to understand the effect of the maternal inheritance of chirality on reproductive isolation and gene flow. We found that the mitochondrial DNA phylogeny of Euhadra is consistent with a single, relatively ancient evolution of sinistral species and suggests either recent "single-gene speciation" or gene flow between chiral morphs that are unable to mate. To clarify the conditions under which new chiral morphs might evolve and whether single-gene speciation can occur, we developed a mathematical model that is relevant to any maternal-effect gene. The model shows that reproductive character displacement can promote the evolution of new chiral morphs, tending to counteract the positive frequency-dependent selection that would otherwise drive the more common chiral morph to fixation. This therefore suggests a general mechanism as to how chiral variation arises in snails. In populations that contain both chiral morphs, two different situations are then possible. In the first, gene flow is substantial between morphs even without interchiral mating, because of the maternal inheritance of chirality. In the second, reproductive isolation is possible but unstable, and will also lead to gene flow if intrachiral matings occasionally produce offspring with the opposite chirality. Together, the results imply that speciation by chiral reversal is only meaningful in the context of a complex biogeographical process, and so must usually involve other factors. In order to understand the roles of reproductive character displacement and gene flow in the chiral evolution of Euhadra, it will be

  2. Application of chiral thiazolidine ligands to asymmetric hydrosilation

    Institute of Scientific and Technical Information of China (English)

    李弘; 姚金水; 何炳林

    1997-01-01

    Seven chiral thiazolidines bound rhodium complexes were synthesized and their catalytic asymmetric hydrosilation properties were investigated It was found through investigation that the configuration of newly formed chiral centre C2 of substituted chiral thiazolidines prepared from L-cysteine or its esters has no effect on the final results of catalytic asymmetric hydrosilation.The direct reason for causing this phenomenon is reported by the present quantitative results for the first time:the rapid racemation of chiral center C2 of chiral thiazolidine ligands takes place under the catalysis of rhodium(Ⅰ) complex [Rh(COD)CI]2

  3. Fluctuations of Goldstone modes and the chiral transition in QCD

    CERN Document Server

    Karsch, Frithjof

    2008-01-01

    We provide evidence for the influence of thermal fluctuations of Goldstone modes on the chiral condensate at finite temperature. We show that at fixed temperature, Tchiral transition temperature this leads to a characteristic dependence of the chiral condensate on the square root of the light quark mass (m_l), which is expected for 3-dimensional models with broken O(N) symmetry. As a consequence the chiral susceptibility shows a strong quark mass dependence for all temperatures below Tc and diverges like 1/sqrt(m_l) in the chiral limit.

  4. Chiroptical studies on supramolecular chirality of molecular aggregates.

    Science.gov (United States)

    Sato, Hisako; Yajima, Tomoko; Yamagishi, Akihiko

    2015-10-01

    The attempts of applying chiroptical spectroscopy to supramolecular chirality are reviewed with a focus on vibrational circular dichroism (VCD). Examples were taken from gels, solids, and monolayers formed by low-molecular mass weight chiral gelators. Particular attention was paid to a group of gelators with perfluoroalkyl chains. The effects of the helical conformation of the perfluoroalkyl chains on the formation of chiral architectures are reported. It is described how the conformation of a chiral gelator was determined by comparing the experimental and theoretical VCD spectra together with a model proposed for the molecular aggregation in fibrils. The results demonstrate the potential utility of the chiroptical method in analyzing organized chiral aggregates.

  5. Expanding proteomics into the analysis of chiral drugs.

    Science.gov (United States)

    Sui, Jianjun; Zhang, Jianhua; Ching, Chi Bun; Chen, Wei Ning

    2009-06-01

    The chiralities of chiral drugs have been investigated extensively with the purpose of enlightening the role of chirality in drug action. Proteomics, though in its infancy, has recently emerged as the foremost technology in drug development research, possessing the advantage of providing more useful information about an organism than genomics, as it directly addresses the level of genome products and their interactions. In this review, we will discuss the background of chiral drug investigation from which contemporary drug chirality research has emerged, the techniques involved in proteomics technology, the application of proteomics in this exciting area, and the perspectives in future applications of this field.

  6. Nematic twist cell: Strong chirality induced at the surfaces

    Science.gov (United States)

    Lin, Tzu-Chieh; Nemitz, Ian R.; Pendery, Joel S.; Schubert, Christopher P. J.; Lemieux, Robert P.; Rosenblatt, Charles

    2013-04-01

    A nematic twist cell having a thickness gradient was filled with a mixture containing a configurationally achiral liquid crystal (LC) and chiral dopant. A chiral-based linear electrooptic effect was observed on application of an ac electric field. This "electroclinic effect" varied monotonically with d, changing sign at d =d0 where the chiral dopant exactly compensated the imposed twist. The results indicate that a significant chiral electrooptic effect always exists near the surfaces of a twist cell containing molecules that can be conformationally deracemized. Additionally, this approach can be used to measure the helical twisting power (HTP) of a chiral dopant in a liquid crystal.

  7. Fabrication and characterization of three-dimensional biomimetic chiral composites.

    Science.gov (United States)

    Turner, Mark D; Schröder-Turk, Gerd E; Gu, Min

    2011-05-09

    Here we show the fabrication and characterization of a novel class of biomimetic photonic chiral composites inspired by a recent finding in butterfly wing-scales. These three-dimensional networks have cubic symmetry, are fully interconnected, have robust mechanical strength and possess chirality which can be controlled through the composition of multiple chiral networks, providing an excellent platform for developing novel chiral materials. Using direct laser writing we have fabricated different types of chiral composites that can be engineered to form novel photonic devices. We experimentally show strong circular dichroism and compare with numerical simulations to illustrate the high quality of these three-dimensional photonic structures.

  8. Chirally symmetric but confined hadrons at finite density

    CERN Document Server

    Glozman, L Ya

    2008-01-01

    At a critical finite chemical potential and low temperature QCD undergoes the chiral restoration phase transition. The folklore tradition is that simultaneously hadrons are deconfined and there appears the quark matter. We demonstrate that it is possible to have confined but chirally symmetric hadrons at a finite chemical potential and hence beyond the chiral restoration point at a finite chemical potential and low temperature there could exist a chirally symmetric matter consisting of chirally symmetric but confined hadrons. If it does happen in QCD, then the QCD phase diagram should be reconsidered with obvious implications for heavy ion programs and astrophysics.

  9. When Chiral Photons Meet Chiral Fermions: Photoinduced Anomalous Hall Effects in Weyl Semimetals

    Science.gov (United States)

    Chan, Ching-Kit; Lee, Patrick A.; Burch, Kenneth S.; Han, Jung Hoon; Ran, Ying

    2016-01-01

    The Weyl semimetal is characterized by three-dimensional linear band touching points called Weyl nodes. These nodes come in pairs with opposite chiralities. We show that the coupling of circularly polarized photons with these chiral electrons generates a Hall conductivity without any applied magnetic field in the plane orthogonal to the light propagation. This phenomenon comes about because with all three Pauli matrices exhausted to form the three-dimensional linear dispersion, the Weyl nodes cannot be gapped. Rather, the net influence of chiral photons is to shift the positions of the Weyl nodes. Interestingly, the momentum shift is tightly correlated with the chirality of the node to produce a net anomalous Hall signal. Application of our proposal to the recently discovered TaAs family of Weyl semimetals leads to an order-of-magnitude estimate of the photoinduced Hall conductivity which is within the experimentally accessible range.

  10. Peak of Chiral Susceptibility and Chiral Phase Transition in QED3

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-Qing; YANG Yong-Hong

    2011-01-01

    A general expression for the scalar susceptibility in QEDs is given. We adopt the Dyson-Schwinger equation for the fermion propagator to solve xc within a range of the number of fermion flavors, N, in chiral symmetry breaking phase. We show that the scalar susceptibility has a peak and the corresponding N is less than the critical number of fermion flavors for chiral symmetry.%@@ A general expression for the scalar susceptibility in QED3 is given.We adopt the Dyson-Schwinger equation for the fermion propagator to solve Xc within a range of the number of fermion flavors, N, in chiral symmetry breaking phase.We show that the scalar susceptibility has a peak and the corresponding N is less than thecritical number of fermion flavors for chiral symmetry.

  11. Synthesis of a Chiral Crystal Form of MOF-5, CMOF-5, by Chiral Induction.

    Science.gov (United States)

    Zhang, Shi-Yuan; Li, Dan; Guo, Dong; Zhang, Hui; Shi, Wei; Cheng, Peng; Wojtas, Lukasz; Zaworotko, Michael J

    2015-12-16

    Chiral variants of the prototypal metal-organic framework MOF-5, Λ-CMOF-5 and Δ-CMOF-5, have been synthesized by preparing MOF-5 in the presence of L-proline or D-proline, respectively. CMOF-5 crystallizes in chiral space group P213 instead of Fm3̅m as exhibited by MOF-5. The phase purity of CMOF-5 was validated by single-crystal and powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption, microanalysis, and solid-state vibrational circular dichroism. CMOF-5 undergoes a reversible single crystal-to-single crystal phase change to MOF-5 when immersed in a variety of organic solvents, although N-methyl-2-pyrrolidone (NMP) does not induce loss of chirality. Indeed, MOF-5 undergoes chiral induction when immersed in NMP, affording racemic CMOF-5.

  12. Enantiopure Ferrocene-Based Planar-Chiral Iridacycles: Stereospecific Control of Iridium-Centred Chirality.

    Science.gov (United States)

    Arthurs, Ross A; Ismail, Muhammad; Prior, Christopher C; Oganesyan, Vasily S; Horton, Peter N; Coles, Simon J; Richards, Christopher J

    2016-02-24

    Reaction of [IrCp*Cl2 ]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p-MeOC6 H4 ) results in ferrocene C-H activation and the diastereoselective synthesis of half-sandwich iridacycles of relative configuration Sp *,RIr *. Extension to (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal-based pseudo-tetrahedral chirality, to give both neutral and cationic half-sandwich iridacycles of absolute configuration Sc ,Sp ,RIr . Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal-centred chirality through an iron-iridium interaction in the coordinatively unsaturated cationic intermediate.

  13. Spintronics and chirality: spin selectivity in electron transport through chiral molecules.

    Science.gov (United States)

    Naaman, Ron; Waldeck, David H

    2015-04-01

    Recent experiments have demonstrated that the electron transmission yield through chiral molecules depends on the electron spin orientation. This phenomenon has been termed the chiral-induced spin selectivity (CISS) effect, and it provides a challenge to theory and promise for organic molecule-based spintronic devices. This article reviews recent developments in our understanding of CISS. Different theoretical models have been used to describe the effect; however, they all presume an unusually large spin-orbit coupling in chiral molecules for the effect to display the magnitudes seen in experiments. A simplified model for an electron's transport through a chiral potential suggests that these large couplings can be manifested. Techniques for measuring spin-selective electron transport through molecules are overviewed, and some examples of recent experiments are described. Finally, we present results obtained by studying several systems, and we describe the possible application of the CISS effect for memory devices.

  14. Intelligent Chiral Sensing Based on Supramolecular and Interfacial Concepts

    Directory of Open Access Journals (Sweden)

    Hironori Izawa

    2010-07-01

    Full Text Available Of the known intelligently-operating systems, the majority can undoubtedly be classed as being of biological origin. One of the notable differences between biological and artificial systems is the important fact that biological materials consist mostly of chiral molecules. While most biochemical processes routinely discriminate chiral molecules, differentiation between chiral molecules in artificial systems is currently one of the challenging subjects in the field of molecular recognition. Therefore, one of the important challenges for intelligent man-made sensors is to prepare a sensing system that can discriminate chiral molecules. Because intermolecular interactions and detection at surfaces are respectively parts of supramolecular chemistry and interfacial science, chiral sensing based on supramolecular and interfacial concepts is a significant topic. In this review, we briefly summarize recent advances in these fields, including supramolecular hosts for color detection on chiral sensing, indicator-displacement assays, kinetic resolution in supramolecular reactions with analyses by mass spectrometry, use of chiral shape-defined polymers, such as dynamic helical polymers, molecular imprinting, thin films on surfaces of devices such as QCM, functional electrodes, FET, and SPR, the combined technique of magnetic resonance imaging and immunoassay, and chiral detection using scanning tunneling microscopy and cantilever technology. In addition, we will discuss novel concepts in recent research including the use of achiral reagents for chiral sensing with NMR, and mechanical control of chiral sensing. The importance of integration of chiral sensing systems with rapidly developing nanotechnology and nanomaterials is also emphasized.

  15. Chiral-field microwave antennas (Chiral microwave near fields for far-field radiation)

    CERN Document Server

    Kamenetskii, E O; Shavit, R

    2015-01-01

    In a single-element structure we obtain a radiation pattern with a squint due to chiral microwave near fields originated from a magnetostatic-mode ferrite disk. At the magnetostatic resonances, one has strong subwavelength localization of energy of microwave radiation. Magnetostatic oscillations in a thin ferrite disk are characterized by unique topological properties: the Poynting-vector vortices and the field helicity. The chiral-topology near fields allow obtaining unique phase structure distribution for far-field microwave radiation.

  16. Proline Based Chiral Ionic Liquids for Enantioselective Michael Reaction

    Directory of Open Access Journals (Sweden)

    Kaoru Nobuoka

    2014-01-01

    Full Text Available Chiral ionic liquids, starting from (S-proline, have been prepared and evaluated the ability of a chiral catalyst. In Michael reaction of trans-β-nitrostyrene and cyclohexanone, all the reactions were carried out under homogeneous conditions without any solvent except for excess cyclohexanone. The chiral ionic liquid catalyst with the positive charge delocalized bulky pyrrolidinium cation shows excellent yields (up to 92%, diastereoselectivities (syn/anti = 96/4, and enantioselectivities (up to 95% ee and could be reused at least three times without any loss of its catalytic activity. Such results demonstrated a promising new approach for green and economic chiral synthesis by using the chiral ionic liquids as a chiral catalyst and a chiral medium.

  17. Chiral Orbifold Construction Of Field Theories With Extra Dimensions

    CERN Document Server

    Hailu, G

    2003-01-01

    We build higher dimensional field theories which have chiral fermion zero-modes on orbifolds. We show that orbifold boundary conditions and scalar vacuum expectation values interplay to produce chiral fermions localized on fat three branes. We develop a scheme for computing field propagators in higher dimensional theories obeying chiral orbifold boundary conditions. Using this scheme we compute the loop corrections to an effective field theory in five dimensions. We find that the renormalization group running of the higher dimensional bulk theory leads to a running of the four dimensional brane couplings. We generalize an argument to verify that the chiral anomaly that arises in these chiral orbifold theories is entirely confined on and uniformly distributed over the fixed points of the orbifold, independent of the shape of the chiral zero-modes. We construct a setup in which a scalar field with appropriate profile in the extra dimension is used to address the hierarchy problem and also localize both chiral f...

  18. Chiral spiral induced by a strong magnetic field

    Directory of Open Access Journals (Sweden)

    Abuki Hiroaki

    2016-01-01

    Full Text Available We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it brings a “continent” of chiral spiral in the phase diagram, by which the chiral tricritical point is totally washed out. This is the case no matter how small the intensity of magnetic field is. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However, the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

  19. Chirality detection of enantiomers using twisted optical metamaterials

    Science.gov (United States)

    Zhao, Yang; Askarpour, Amir N.; Sun, Liuyang; Shi, Jinwei; Li, Xiaoqin; Alù, Andrea

    2017-01-01

    Many naturally occurring biomolecules, such as amino acids, sugars and nucleotides, are inherently chiral. Enantiomers, a pair of chiral isomers with opposite handedness, often exhibit similar physical and chemical properties due to their identical functional groups and composition, yet show different toxicity to cells. Detecting enantiomers in small quantities has an essential role in drug development to eliminate their unwanted side effects. Here we exploit strong chiral interactions with plasmonic metamaterials with specifically designed optical response to sense chiral molecules down to zeptomole levels, several orders of magnitude smaller than what is typically detectable with conventional circular dichroism spectroscopy. In particular, the measured spectra reveal opposite signs in the spectral regime directly associated with different chiral responses, providing a way to univocally assess molecular chirality. Our work introduces an ultrathin, planarized nanophotonic interface to sense chiral molecules with inherently weak circular dichroism at visible and near-infrared frequencies. PMID:28120825

  20. Chiral phase transition in QED3 at finite temperature

    Science.gov (United States)

    Yin, Pei-Lin; Xiao, Hai-Xiao; Wei, Wei; Feng, Hong-Tao; Zong, Hong-Shi

    2016-12-01

    In the framework of Dyson-Schwinger equations, we employ two kinds of criteria (one kind is the chiral condensate, the other kind is thermodynamic quantities, such as the pressure, the entropy, and the specific heat) to investigate the nature of chiral phase transitions in QED3 for different fermion flavors. It is found that the chiral phase transitions in QED3 for different fermion flavors are all typical second-order phase transitions; the critical temperature and order of the chiral phase transition obtained from the chiral condensate and susceptibility are the same with that obtained by the thermodynamic quantities, which means that they are equivalent in describing the chiral phase transition; the critical temperature decreases as the number of fermion flavors increases and there is a boundary that separates the Tc-Nf plane into chiral symmetry breaking and restoration regions.

  1. Cooperative expression of atomic chirality in inorganic nanostructures

    Science.gov (United States)

    Wang, Peng-Peng; Yu, Shang-Jie; Govorov, Alexander O.; Ouyang, Min

    2017-02-01

    Cooperative chirality phenomena extensively exist in biomolecular and organic systems via intra- and inter-molecular interactions, but study of inorganic materials has been lacking. Here we report, experimentally and theoretically, cooperative chirality in colloidal cinnabar mercury sulfide nanocrystals that originates from chirality interplay between the crystallographic lattice and geometric morphology at different length scales. A two-step synthetic scheme is developed to allow control of critical parameters of these two types of handedness, resulting in different chiral interplays expressed as observables through materials engineering. Furthermore, we adopt an electromagnetic model with the finite element method to elucidate cooperative chirality in inorganic systems, showing excellent agreement with experimental results. Our study enables an emerging class of nanostructures with tailored cooperative chirality that is vital for fundamental understanding of nanoscale chirality as well as technology applications based on new chiroptical building blocks.

  2. Chirality detection of enantiomers using twisted optical metamaterials

    Science.gov (United States)

    Zhao, Yang; Askarpour, Amir N.; Sun, Liuyang; Shi, Jinwei; Li, Xiaoqin; Alù, Andrea

    2017-01-01

    Many naturally occurring biomolecules, such as amino acids, sugars and nucleotides, are inherently chiral. Enantiomers, a pair of chiral isomers with opposite handedness, often exhibit similar physical and chemical properties due to their identical functional groups and composition, yet show different toxicity to cells. Detecting enantiomers in small quantities has an essential role in drug development to eliminate their unwanted side effects. Here we exploit strong chiral interactions with plasmonic metamaterials with specifically designed optical response to sense chiral molecules down to zeptomole levels, several orders of magnitude smaller than what is typically detectable with conventional circular dichroism spectroscopy. In particular, the measured spectra reveal opposite signs in the spectral regime directly associated with different chiral responses, providing a way to univocally assess molecular chirality. Our work introduces an ultrathin, planarized nanophotonic interface to sense chiral molecules with inherently weak circular dichroism at visible and near-infrared frequencies.

  3. Enantioselective Nanoporous Carbon Based on Chiral Ionic Liquids.

    Science.gov (United States)

    Fuchs, Ido; Fechler, Nina; Antonietti, Markus; Mastai, Yitzhak

    2016-01-04

    One of the greatest challenges in modern chemical processing is to achieve enantiospecific control in chemical reactions using chiral media such as chiral mesoporous materials. Herein, we describe a novel and effective synthetic pathway for the preparation of enantioselective nanoporous carbon, based on chiral ionic liquids (CILs). CILs of phenylalanine (CIL(Phe)) are used as precursors for the carbonization of chiral mesoporous carbon. We employ circular dichroism spectroscopy, isothermal titration calorimetry (ITC), and chronoamperometry in order to demonstrate the chiral nature of the mesoporous carbon. The approach presented in this paper is highly significant for the development of a new type of chiral porous materials for enantioselective chemistry. In addition, it contributes significantly to our understanding of the structure and nature of chiral nanoporous materials and surfaces. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Synthesis of Chiral Building Blocks for Use in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Rustum S. Boyce

    2004-05-01

    Full Text Available In the past decade there has been a significant growth in the sales of pharmaceutical drugs worldwide, but more importantly there has been a dramatic growth in the sales of single enantiomer drugs. The pharmaceutical industry has a rising demand for chiral intermediates and research reagents because of the continuing imperative to improve drug efficacy. This in turn impacts on researchers involved in preclinical discovery work. Besides traditional chiral pool and resolution of racemates as sources of chiral building blocks, many new synthetic methods including a great variety of catalytic reactions have been developed which facilitate the production of complex chiral drug candidates for clinical trials. The most ambitious technique is to synthesise homochiral compounds from non-chiral starting materials using chiral metal catalysts and related chemistry. Examples of the synthesis of chiral building blocks from achiral materials utilizing asymmetric hydrogenation and asymmetric epoxidation are presented.

  5. Symmetries of hadrons after unbreaking the chiral symmetry

    CERN Document Server

    Glozman, L Ya; Schröck, M

    2012-01-01

    We study hadron correlators upon artificial restoration of the spontaneously broken chiral symmetry. In a dynamical lattice simulation we remove the lowest lying eigenmodes of the Dirac operator from the valence quark propagators and study evolution of the hadron masses obtained. All mesons and baryons in our study, except for a pion, survive unbreaking the chiral symmetry and their exponential decay signals become essentially better. From the analysis of the observed spectroscopic patterns we conclude that confinement still persists while the chiral symmetry is restored. All hadrons fall into different chiral multiplets. The broken U(1)_A symmetry does not get restored upon unbreaking the chiral symmetry. We also observe signals of some higher symmetry that includes chiral symmetry as a subgroup. Finally, from comparison of the \\Delta - N splitting before and after unbreaking of the chiral symmetry we conclude that both the color-magnetic and the flavor-spin quark-quark interactions are of equal importance.

  6. Preparation of Chiral 1,4-Phenylene-silicas via Chiral Low-molecular-weight Amphiphiles

    Institute of Scientific and Technical Information of China (English)

    XIAO Min; LIU Xiao-juan; HU Kai; WU Li-min; LI Yi; LI Bao-zong; YANG Yong-gang

    2012-01-01

    Chiral organic-inorganic hybrid silicas can be prepared via the self-assemblies of chiral surfactants and gelators as templates.However,the relationship between the chirality of the hybrid silica and the structure of the surfactant/gelator has not been systemically studied.Herein,a series of chiral low-molecular-weight amphiphiles(LMWAs) derived from L-valine was synthesized.Their alkyl chains were n-butadecyl,n-hexadecyl and n-octadecyl,respectively.They can form viscous liquids in pure water,and physical gels in tetrahydrofuran,cyclohexanone,acetonitrile,acetone,chlorobenzene and nitrobenzenc.Chiral 1,4-phenylene-silicas were prepared via the self-assemblies of these LMWAs as templates.With increasing the alkyl chain length,the 1,4-phenylene-silicas changed from short mesoporous nanorods to long nanotubcs. The circular dichroism spectra of the 1,4-phenylene-silicas indicated that the long nanotubes exhibit the strongest chirality.

  7. Use of chiral amino acid ester-based ionic liquids as chiral selectors in CE.

    Science.gov (United States)

    Stavrou, Ioannis J; Kapnissi-Christodoulou, Constantina P

    2013-02-01

    In this study, the applicability of a chiral ionic liquid (CIL) as the sole chiral selector in CE was investigated for the first time. In particular, five amino acid ester-based CILs were synthesized and used as additives in the BGE in order to evaluate their chiral recognition ability. The performance of these CILs as the sole chiral selectors was evaluated by using 1,1'-binaphthyl-2,2-diylhydrogenphosphate (BNP) as the analyte and by comparing the resolution values. Different parameters were examined, such as the alkyl group bulkiness and the configuration of the cation, the anion type of the CIL and its concentration, and the pH of the BGE, in order to optimize the separation of the enantiomers and to demonstrate the effect that each parameter has on the chiral-recognition ability of the CIL. Baseline separation of BNP within 13 min was achieved by using a BGE of 100 mM Tris/10 mM sodium tetraboratedecahydrate (pH 8) and a chiral selector of 60 mM l-alanine tert butyl ester lactate. The run-to-run and batch-to-batch reproducibilities were also evaluated by computing the %RSD values of the EOF and the two enantiomer peaks. In both cases, very good reproducibilities were observed, since all %RSD values were below 1%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. In Search of the Chiral Regime

    CERN Document Server

    Beane, S R

    2004-01-01

    A critical appraisal is given of a recent analysis of the quark-mass and finite-size dependence of unquenched lattice QCD data for the nucleon mass. We use this forum to estimate the boundary of the chiral regime for nucleon properties.

  9. Quenched QCD near the chiral limit

    CERN Document Server

    Göckeler, M; Petters, D; Pleiter, D; Rakow, P E L; Schierholz, G

    2000-01-01

    A numerical study of quenched QCD for light quarks is presented using O(a)improved fermions. Particular attention is paid to the possible existence anddetermination of quenched chiral logarithms. A `safe' region to use for chiralextrapolations appears to be at and above the strange quark mass.

  10. Chiral superfields in N = 2 supergravity

    NARCIS (Netherlands)

    Roo, M. de; Holten, J.W. van; Wit, B. de; Proeyen, A. Van

    1980-01-01

    The transformation laws of chiral (scalar) superfields with arbitrary Weyl weight w are determined for the U(2) superconformal theory. A superconformally invariant density is given for fields with w = 2. For w = 1 it is possible to have smaller irreducible multiplets. The full restriction upon which

  11. Baryon form factors in chiral perturbation theory

    CERN Document Server

    Kubis, B; Kubis, Bastian; Meissner, Ulf-G.

    2001-01-01

    We analyze the electromagnetic form factors of the ground state baryon octet to fourth order in relativistic baryon chiral perturbation theory. Predictions for the \\Sigma^- charge radius and the \\Lambda-\\Sigma^0 transition moment are found to be in excellent agreement with the available experimental information. Furthermore, the convergence behavior of the hyperon charge radii is shown to be more than satisfactory.

  12. Electroweak Chiral Lagrangian for Neutral Higgs Boson

    Institute of Scientific and Technical Information of China (English)

    WANG Shun-Zhi; WANG Qing

    2008-01-01

    A neutral Higgs boson is added into the traditional electroweak chiral Lagrangian by writing down all possible high dimension operators. The matter part of the Lagrangian is investigated in detail. We find that if Higgs field dependence of Yukawa couplings can be factorized out, there will be no flavour changing neutral couplings; neutral Higgs can induce coupling between light and heavy neutrinos.

  13. Chiral Thermodynamics in a finite box

    CERN Document Server

    Juričić, Ana

    2016-01-01

    Finite-volume modifications of the two-flavor chiral phase diagram are investigated within an effective quark-meson model in various mean-field approximations. The role of vacuum fluctuations and boundary conditions, their influence on higher cumulants and signatures of a possible pseudo-critical endpoint are amplified with smaller volumes.

  14. The Chiral Bilayer Effect Stabilizes Micellar Fibers

    NARCIS (Netherlands)

    Fuhrhop, Jürgen-Hinrich; Schnieder, Peter; Rosenberg, Jörg; Boekema, Egbert

    1987-01-01

    Dihelical fibers several micrometers in length and gels were obtained by spontaneous aggregation of octyl L- and D-gluconamides. The single strands have the thickness of a bimolecular layer. No fibers are formed from the racemate. The tendency of the chiral amphiphiles to aggregate to very long fibe

  15. Separation of Chiral Active Pharmaceutical Ingredients

    DEFF Research Database (Denmark)

    Chaaban, Joussef Hussein

    is regarded as a first step towards a fully continuous PC process. The current knowledge of the importance of crystallization processes in the pharmaceutical industry and the complex thermodynamic and kinetic phenomena accompanied with the separation of chiral compounds are addressed. The experimental work...

  16. Orientifold Planar Equivalence: The Chiral Condensate

    DEFF Research Database (Denmark)

    Armoni, Adi; Lucini, Biagio; Patella, Agostino

    2008-01-01

    The recently introduced orientifold planar equivalence is a promising tool for solving non-perturbative problems in QCD. One of the predictions of orientifold planar equivalence is that the chiral condensates of a theory with $N_f$ flavours of Dirac fermions in the symmetric (or antisymmetric...

  17. Anomalous Hall Effect for chiral fermions

    CERN Document Server

    Zhang, P -M

    2014-01-01

    Semiclassical chiral fermions manifest the anomalous spin-Hall effect: when put into a pure electric field, they suffer a side jump, analogous to what happens to their massive counterparts in non-commutative mechanics. The transverse shift is consistent with the conservation of the angular momentum. In a pure magnetic field a cork-screw-like, spiraling motion is found.

  18. Leading chiral logarithms for the nucleon mass

    Energy Technology Data Exchange (ETDEWEB)

    Vladimirov, Alexey A.; Bijnens, Johan [Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, SE 223 62 Lund (Sweden)

    2016-01-22

    We give a short introduction to the calculation of the leading chiral logarithms, and present the results of the recent evaluation of the LLog series for the nucleon mass within the heavy baryon theory. The presented results are the first example of LLog calculation in the nucleon ChPT. We also discuss some regularities observed in the leading logarithmical series for nucleon mass.

  19. On chiral differential operators over homogeneous spaces

    Directory of Open Access Journals (Sweden)

    Vassily Gorbounov

    2001-01-01

    Full Text Available We give a classification and construction of chiral algebras of differential operators over semisimple algebraic groups G and over homogeneous spaces G/N and G/P where N is a nilpotent and P a parabolic subgroup.

  20. Chiral Corrections to Vector Meson Decay Constants

    CERN Document Server

    Bijnens, J; Talavera, P; Bijnens, Johan; Gosdzinsky, Peter; Talavera, Pere

    1998-01-01

    We calculate the leading quark mass corrections of order $m_q\\log(m_q)$, $m_q$ and $m_q^{3/2}$ to the vector meson decay constants within Heavy Vector Meson Chiral Perturbation Theory. We discuss the issue of electromagnetic gauge invariance and the heavy mass expansion. Reasonably good fits to the observed decay constants are obtained.

  1. From Ostwald Ripening to Single Chirality

    NARCIS (Netherlands)

    Noorduin, Wim L.; Vlieg, Elias; Kellogg, Richard M.; Kaptein, Bernard

    2009-01-01

    A century ago Wilhelm Ostwald received the Nobel Prize for Chemistry. Although Ostwald was never significantly involved with the phenomenon of chirality, one of his discoveries, Ostwald ripening, is thought to be involved in a recently discovered method in which grinding-induced attrition is used to

  2. ISOSPIN BREAKING AND THE CHIRAL CONDENSATE.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ, M.

    2005-07-25

    With two degenerate quarks, the chiral condensate exhibits a jump as the quark masses pass through zero. I discuss how this single transition splits into two Ising like transitions when the quarks are made non-degenerate. The order parameter is the expectation of the neutral pion field. The transitions represent long distance coherent phenomena occurring without the Dirac operator having vanishingly small eigenvalues.

  3. Finite Density QCD in the Chiral Limit

    CERN Document Server

    Aloisio, R; Di Carlo, G; Galante, A; Grillo, A F

    1998-01-01

    We present the first results of an exact simulation of full QCD at finite density in the chiral limit. We have used a MFA (Microcanonical Fermionic Average) inspired approach for the reconstruction of the Grand Canonical Partition Function of the theory; using the fugacity expansion of the fermionic determinant we are able to move continuously in the ($\\beta -\\mu$) plane with $m=0$.

  4. Field-enlarging transformations and chiral theories

    CERN Document Server

    Sladkowski, J

    1995-01-01

    A field-enlarging transformation in the chiral electrodynamics is performed. This introduces an additional gauge symmetry to the model that is unitary and anomaly-free and allows for comparison of different models discussed in the literature. The problem of superfluous degrees of freedom and their influence on quantization is discussed. Several "mysteries" are explained from this point of view.

  5. Chiral anomaly and transport in Weyl metals

    Science.gov (United States)

    Burkov, A. A.

    2015-03-01

    We present an overview of our recent work on transport phenomena in Weyl metals, which may be connected to their nontrivial topological properties, particularly to chiral anomaly. We argue that there are two basic phenomena, which are related to chiral anomaly in Weyl metals: anomalous Hall effect (AHE) and chiral magnetic effect (CME). While AHE is in principle present in any ferromagnetic metal, we demonstrate that a magnetic Weyl metal is distinguished from an ordinary ferromagnetic metal by the absence of the extrinsic and the Fermi surface part of the intrinsic contributions to the AHE, as long as the Fermi energy is sufficiently close to the Weyl nodes. The AHE in a Weyl metal is thus shown to be a purely intrinsic, universal property, fully determined by the location of the Weyl nodes in the first Brillouin zone. In other words, a ferromagnetic Weyl metal may be thought of as the only example of a ferromagnetic metal with a purely intrinsic AHE. We further develop a fully microscopic theory of diffusive magnetotransport in Weyl metals. We derive coupled diffusion equations for the total and axial (i.e. node-antisymmetric) charge densities and show that chiral anomaly manifests as a magnetic-field-induced coupling between them. We demonstrate that an experimentally-observable consequence of CME in magnetotransport in Weyl metals is a quadratic negative magnetoresistance, which will dominate all other contributions to magnetoresistance under certain conditions and may be regarded as a smoking-gun transport characteristic, unique to Weyl metals.

  6. Chiral damping of magnetic domain walls

    KAUST Repository

    Jué, Emilie

    2015-12-21

    Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics1, current-induced spin–orbit torques2, 3, 4, 5, 6, 7 and some topological magnetic structures8, 9, 10, 11, 12. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii–Moriya interaction (DMI) exhibit identical spatial symmetry13, 14, 15, 16, 17, 18, 19. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. 20).

  7. Chiral thiols. Synthesis and enantiomeric excess determination

    NARCIS (Netherlands)

    Strijtveen, Bernardus Wilhelmus Maria

    1987-01-01

    Chiral thiols are a class of chira compounds, which is gaining mone and nore attention the last decenniun. Especially α-mercaptocarboxylic acids are frequently found as a structunal unit in (biologically) important products. As a consequence, many synthetic analoga or derivatives of these natural pr

  8. Magnetic properties in the inhomogeneous chiral phase

    CERN Document Server

    Yoshiike, Ryo; Tatsumi, Toshitaka

    2016-01-01

    We investigate the magnetic properties of quark matter in the inhomogeneous chiral phase, where both scalar and pseudoscalar condensates spatially modulate. The energy spectrum of the lowest Landau level becomes asymmetric about zero in the external magnetic field, and gives rise to the remarkably magnetic properties: quark matter has a spontaneous magnetization, while the magnetic susceptibility does not diverge on the critical point.

  9. The Many Uses of Chiral Effective Theories

    NARCIS (Netherlands)

    Pallante, Elisabetta

    2008-01-01

    I review basic concepts of chiral effective field theories guided by an historical perspective: from the first ideas to the merging with other effective frameworks, and to the interplay with lattice field theory. The impact of recent theoretical developments on phenomenological predictions is review

  10. Chiral interpolation in a finite volume

    CERN Document Server

    Fukaya, H; Hashimoto, S; Kaneko, T; Matsufuru, H; Noaki, J; Onogi, T; Yamada, N

    2011-01-01

    A simulation of lattice QCD at (or even below) the physical pion mass is feasible on a small lattice size of \\sim 2 fm. The results are, however, subject to large finite volume effects. In order to precisely understand the chiral behavior in a finite volume, we develop a new computational scheme to interpolate the conventional epsilon and p regimes within chiral perturbation theory. In this new scheme, we calculate the two-point function in the pseudoscalar channel, which is described by a set of Bessel functions in an infra-red finite way as in the epsilon regime, while chiral logarithmic effects are kept manifest as in the p regime. The new ChPT formula is compared to our 2+1- flavor lattice QCD data near the physical up and down quark mass, mud \\sim 3 MeV on an L \\sim 1.8 fm lattice. We extract the pion mass = 99(4) MeV, from which we attempt a chiral "interpolation" of the observables to the physical point.

  11. Fermion Determinant with Dynamical Chiral Symmetry Breaking

    Institute of Scientific and Technical Information of China (English)

    LU Qin; YANG Hua; WANG Qing

    2002-01-01

    One-loop fermion determinant is discussed for the case in which the dynamical chiral symmetry breakingcaused by momentum-dependent fermion self-energy ∑(p2) takes place. The obtained series generalizes the heat kernelexpansion for hard fermion mass.

  12. Chiral Block Copolymer Structures for Metamaterial Applications

    Science.gov (United States)

    2015-01-27

    MONITOR’S REPORT NUMBER(S) AOARD-114078 12. DISTRIBUTION/AVAILABILITY STATEMENT Distribution A: Approved for public release. Distribtion is...researchers focused o synthesis and processing, morphology and physical characterization of chiral block copolymer (BCP) materials. Such materials a...developed a platform process technology that can fabricate novel netwo morphologies from initial bicontinuous cubic phases through supergroup/subgroup

  13. Chiral symmetry breaking, instantons, and monopoles

    CERN Document Server

    Di Giacomo, Adriano

    2015-01-01

    The purpose of this study is to show that monopoles induce the chiral symmetry breaking. In order to indicate the evidence, we add one pair of monopoles with magnetic charges to the quenched SU(3) configurations by a monopole creation operator, and investigate the propaties of the chiral symmetry breaking using the Overlap fermion. We show that instantons are created by the monopoles. The pseudoscalar meson mass and decay constant are computed from the correlation functions, and the renormalization constant $Z_{S}$ is determined by the non perturbative method. The renormalization group invariant chiral condensate in $\\overline{\\mbox{MS}}$-scheme at 2 [GeV] is evaluated by the Gell-Mann-Oakes-Renner formula, and the random matrix theory. Finally, we estimate the renormalization group invariant quark masses $\\bar{m} = (m_{u} + m_{d})/2$, and $m_{s}$ in $\\overline{\\mbox{MS}}$-scheme at 2 [GeV]. The preliminary results indicate that the chiral condensate decreases and the quark masses become slightly heavy by inc...

  14. The Chiral Bilayer Effect Stabilizes Micellar Fibers

    NARCIS (Netherlands)

    Fuhrhop, Jürgen-Hinrich; Schnieder, Peter; Rosenberg, Jörg; Boekema, Egbert

    1987-01-01

    Dihelical fibers several micrometers in length and gels were obtained by spontaneous aggregation of octyl L- and D-gluconamides. The single strands have the thickness of a bimolecular layer. No fibers are formed from the racemate. The tendency of the chiral amphiphiles to aggregate to very long

  15. Chiral damping of magnetic domain walls

    Science.gov (United States)

    Jué, Emilie; Safeer, C. K.; Drouard, Marc; Lopez, Alexandre; Balint, Paul; Buda-Prejbeanu, Liliana; Boulle, Olivier; Auffret, Stephane; Schuhl, Alain; Manchon, Aurelien; Miron, Ioan Mihai; Gaudin, Gilles

    2016-03-01

    Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics, current-induced spin-orbit torques and some topological magnetic structures. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii-Moriya interaction (DMI) exhibit identical spatial symmetry. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. ).

  16. On the Chiral imbalance and Weibel Instabilities

    CERN Document Server

    Kumar, Avdhesh; Kaw, Predhiman K

    2016-01-01

    We study the chiral-imbalance and the Weibel instabilities in presence of the quantum anomaly using the Berry-curvature modified kinetic equation. We argue that in many realistic situations, e.g. relativistic heavy-ion collisions, both the instabilities can occur simultaneously. The Weibel instability depends on the momentum anisotropy parameter $\\xi$ and the angle ($\\theta_n$) between the propagation vector and the anisotropy direction. It has maximum growth rate at $\\theta_n=0$ while $\\theta_n=\\pi/2$ corresponds to a damping. On the other hand the pure chiral-imbalance instability occurs in an isotropic plasma and depends on difference between the chiral chemical potentials of right and left-handed particles. It is shown that when $\\theta_n=0$, only for a very small values of the anisotropic parameter $\\xi\\sim \\xi_c$, growth rates of the both instabilities are comparable. For the cases $\\xi_c<\\xi\\ll1$, $\\xi\\approx 1$ or $\\xi \\geq 1$ at $\\theta_n=0$, the Weibel modes dominate over the chiral-imbalance ins...

  17. Effective action for supersymmetric chiral anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Krivoshchekov, V.K.; Chekhov, L.O.

    1987-05-01

    It is shown that consistency conditions of the type of the Wess-Zumino conditions are necessary and sufficient conditions for local integrability of the supersymmetric chiral anomaly. It follows from the requirement of global integrability that the coefficient of the anomalous action is discrete. Explicit expressions are obtained for consistent anomalies and the corresponding functionals, which depend on superfields of various types.

  18. Chiral separation and twin-beam photonics

    Science.gov (United States)

    Bradshaw, David S.; Andrews, David L.

    2016-03-01

    It is well-known that, in a homogeneous fluid medium, most optical means that afford discrimination between molecules of opposite handedness are intrinsically weak effects. The reason is simple: the wide variety of origins for differential response commonly feature real or virtual electronic transitions that break a parity condition. Despite being electric dipole allowed, they manifest the chirality of the material in which they occur by breaking a selection rule that would otherwise preclude the simultaneous involvement of magnetic dipole or electric quadrupole forms of coupling. Although the latter are typically weaker than electric dipole effects by several orders of magnitude, it is the involvement of these weak forms of interaction that are responsible for chiral sensitivity. There have been a number of attempts to cleverly exploit novel optical configurations to enhance the relative magnitude - and hence potentially the efficiency - of chiral discrimination. The prospect of success in any such venture is enticing, because of the huge impact that such an advance might be expected to have in the health, food and medical sectors. Some of these proposals have utilized mirror reflection, and others surface plasmon coupling, or optical binding methods. Several recent works in the literature have drawn attention to a further possibility: the deployment of optical beam interference as a means to achieve chiral separations of sizeable extent. In this paper the underlying theory is fully developed to identify the true scope and limitations of such an approach.

  19. Chiral effective field theory and nuclear forces

    CERN Document Server

    Machleidt, R

    2011-01-01

    We review how nuclear forces emerge from low-energy QCD via chiral effective field theory. The presentation is accessible to the non-specialist. At the same time, we also provide considerable detailed information (mostly in appendices) for the benefit of researchers who wish to start working in this field.

  20. The development of chiral nematic mesoporous materials.

    Science.gov (United States)

    Kelly, Joel A; Giese, Michael; Shopsowitz, Kevin E; Hamad, Wadood Y; MacLachlan, Mark J

    2014-04-15

    Cellulose nanocrystals (CNCs) are obtained from the sulfuric acid-catalyzed hydrolysis of bulk cellulose. The nanocrystals have diameters of ~5-15 nm and lengths of ~100-300 nm (depending on the cellulose source and hydrolysis conditions). This lightweight material has mostly been investigated to reinforce composites and polymers because it has remarkable strength that rivals carbon nanotubes. But CNCs have an additional, less explored property: they organize into a chiral nematic (historically referred to as cholesteric) liquid crystal in water. When dried into a thin solid film, the CNCs retain the helicoidal chiral nematic order and assemble into a layered structure where the CNCs have aligned orientation within each layer, and their orientation rotates through the stack with a characteristic pitch (repeating distance). The cholesteric ordering can act as a 1-D photonic structure, selectively reflecting circularly polarized light that has a wavelength nearly matching the pitch. During CNC self-assembly, it is possible to add sol-gel precursors, such as Si(OMe)4, that undergo hydrolysis and condensation as the solvent evaporates, leading to a chiral nematic silica/CNC composite material. Calcination of the material in air destroys the cellulose template, leaving a high surface area mesoporous silica film that has pore diameters of ~3-10 nm. Importantly, the silica is brilliantly iridescent because the pores in its interior replicate the chiral nematic structure. These films may be useful as optical filters, reflectors, and membranes. In this Account, we describe our recent research into mesoporous films with chiral nematic order. Taking advantage of the chiral nematic order and nanoscale of the CNC templates, new functional materials can be prepared. For example, heating the silica/CNC composites under an inert atmosphere followed by removal of the silica leaves highly ordered, mesoporous carbon films that can be used as supercapacitor electrodes. The composition

  1. Role of Achiral Nucleobases in Multicomponent Chiral Self-Assembly: Purine-Triggered Helix and Chirality Transfer.

    Science.gov (United States)

    Deng, Ming; Zhang, Li; Jiang, Yuqian; Liu, Minghua

    2016-11-21

    Chiral self-assembly is a basic process in biological systems, where many chiral biomolecules such as amino acids and sugars play important roles. Achiral nucleobases usually covalently bond to saccharides and play a significant role in the formation of the double helix structure. However, it remains unclear how the achiral nucleobases can function in chiral self-assembly without the sugar modification. Herein, we have clarified that purine nucleobases could trigger N-(9-fluorenylmethox-ycarbonyl) (Fmoc)-protected glutamic acid to self-assemble into helical nanostructures. Moreover, the helical nanostructure could serve as a matrix and transfer the chirality to an achiral fluorescence probe, thioflavin T (ThT). Upon chirality transfer, the ThT showed not only supramolecular chirality but also circular polarized fluorescence (CPL). Without the nucleobase, the self-assembly processes cannot happen, thus providing an example where achiral molecules played an essential role in the expression and transfer of the chirality.

  2. Chiral Sensitivity in Electron-Molecule Interactions

    Science.gov (United States)

    Dreiling, Joan

    2015-09-01

    All molecular forms of life possess a chiral asymmetry, with amino acids and sugars found respectively in L- and D-enantiomers only. The primordial origin of this enantiomeric excess is unknown. One possible explanation is given by the Vester- Ulbricht hypothesis, which suggests that left-handed electrons present in beta-radiation, produced by parity-violating weak decays, interacted with biological precursors and preferentially destroyed one of the two enantiomers. Experimental tests of this idea have thus far yielded inconclusive results. We show direct evidence for chirally-dependent bond breaking through a dissociative electron attachment (DEA) reaction when spin-polarized electrons are incident on gas-phase chiral molecules. This provides unambiguous evidence for a well-defined, chirally-sensitive destructive molecular process and, as such, circumstantial evidence for the Vester-Ulbricht hypothesis. I will also present the results of our systematic study of the DEA asymmetry for different chiral halocamphor molecules. Three halocamphor molecules were investigated: 3-bromocamphor (C10H15BrO), 3-iodocamphor(C10H15IO), and 10-iodocamphor. The DEA asymmetries collected for bromocamphor and iodocamphor are qualitatively different, suggesting that the atomic number of the heaviest atom in the molecule plays a crucial role in the asymmetric interactions. The DEA asymmetry data for 3- and 10-iodocamphor have the same qualitative behavior, but the 10-iodocamphor asymmetry is about twice as large at the lowest energies investigated, so the location of the heavy atom in the camphor molecule also affects the asymmetries. This work was performed at the University of Nebraska-Lincoln. This project is funded by NSF Grant PHY-1206067.

  3. Nuclear chirality, a model and the data

    Science.gov (United States)

    Starosta, K.; Koike, T.

    2017-09-01

    In the last decade, the manifestation of chirality in atomic nuclei has become the subject of numerous experimental and theoretical studies. The common feature of current model calculations is that the chiral geometry of angular momentum coupling is extracted from expectation values of orientation operators, rather than being a starting point in construction of a model. However, using the particle-hole coupling model for triaxial odd-odd nuclei it is possible to construct a basis which contains right-handed, left-handed and planar states of angular momentum coupling. If this basis is used, the chirality is an explicit rather than an extracted feature as in any other models with non-chiral bases. The time-reversal symmetry, which relates the basis states of opposite handedness, can be used to reduce the dimension of matrices for diagonalization of the model Hamiltonian, proving the effectiveness of this approach. Moreover, the final model eigenstate wave functions show a concentration of amplitudes among a relatively small number (˜1%) of components compared to the full model space. In that sense, the ‘chiral’ basis provides a useful tool to examine model predictions providing direct insight into the structure of doublet states. In this work, similarities and differences between the rotational behaviour of an axial and triaxial body provide a starting point for derivation of the basis optimal for valence nucleon coupling to an axial and a triaxial core. The derived ‘chiral’ basis is optimal for coupling of a valence particle and hole to the triaxial core. Model predictions are presented and discussed. A comprehensive review of current experimental data on observed chiral band candidates is also provided.

  4. Baryons in the chiral regime

    Energy Technology Data Exchange (ETDEWEB)

    Knippschild, Bastian

    2012-03-05

    Quantum Chromodynamics (QCD) is the theory of strong interactions, one of the four fundamental forces in our Universe. It describes the interaction of gluons and quarks which build up hadrons like protons and neutrons. Most of the visible matter in our universe is made of protons and neutrons. Hence, we are interested in their fundamental properties like their masses, their distribution of charge and their shape. The only known theoretical, non-perturbative and ab initio method to investigate hadron properties at low energies is lattice Quantum Chromodynamics (lattice QCD). However, up-to-date simulations (especially for baryonic quantities) do not achieve the accuracy of experiments. In fact, current simulations do not even reproduce the experimental values for the form factors. The question arises wether these deviations can be explained by systematic effects in lattice QCD simulations. This thesis is about the computation of nucleon form factors and other hadronic quantities from lattice QCD. So called Wilson fermions are used and the u- and d-quarks are treated fully dynamically. The simulations were performed using gauge ensembles with a range of lattice spacings, volumes and pion masses. First of all, the lattice spacing was set to be able to make contact between the lattice results and their experimental complement and to be able to perform a continuum extrapolation. The light quark mass has been computed and found to be m{sub ud}{sup MS}(2 GeV)=3.03(17)(38) MeV. This value is in good agreement with values from experiments and other lattice determinations. Electro-magnetic and axial form factors of the nucleon have been calculated. From these form factors the nucleon radii and the coupling constants were computed. The different ensembles enabled us to investigate systematically the dependence of these quantities on the volume, the lattice spacing and the pion mass. Finally we perform a continuum extrapolation and chiral extrapolations to the physical point

  5. Optical properties and circular dichroism of chiral metal nanoparticles

    Science.gov (United States)

    Fan, Zhiyuan; Govorov, Alexander; OU Team

    2013-03-01

    In nature, biological systems are built up by homochiral building blocks, such as a sugar and protein. Circular dichroism (CD) is an effective tool of resolving molecular conformations. It utilizes circularly polarized light to detect differential absorption of chiral materials. In medicine, it will help us to develop new drugs and therapies, if we understand the connection between the physical or chemical properties of drug molecules and their conformations. With the rapid development of nanotechnologies, chiral nanomaterials attract lots of attention nowadays. CD signals of chiral molecules can be enhanced or shifted to the visible band in the presence of plasmonic nanocrystals. Here we present a plasmonic CD mechanism from a single chiral metal nanocrystal. The mechanism is essentially different from the dipolar plasmon-plasmon interaction in a chiral NP assembly, which mimics the CD mechanism of chiral molecules. Chiral metal nanocrystals are expected to have promising applications in biosensing. Recently a few experimental papers reported successful realizations of chiral nanocrystals in a macroscopic ensemble in solution. Particularly the paper described silver nanoparticles grown on chiral template molecules and demonstrating characteristic CD signals at a plasmonic wavelength. The plasmonic CD signals in Ref. can come from a dipolar plasmon-molecule interaction or from a chiral shape of nanocrystals. This work was supported by the NSF (project: CBET- 0933782) and by the Volkswagen Foundation.

  6. Chiral corrections to the Adler-Weisberger sum rule

    Science.gov (United States)

    Beane, Silas R.; Klco, Natalie

    2016-12-01

    The Adler-Weisberger sum rule for the nucleon axial-vector charge, gA , offers a unique signature of chiral symmetry and its breaking in QCD. Its derivation relies on both algebraic aspects of chiral symmetry, which guarantee the convergence of the sum rule, and dynamical aspects of chiral symmetry breaking—as exploited using chiral perturbation theory—which allow the rigorous inclusion of explicit chiral symmetry breaking effects due to light-quark masses. The original derivations obtained the sum rule in the chiral limit and, without the benefit of chiral perturbation theory, made various attempts at extrapolating to nonvanishing pion masses. In this paper, the leading, universal, chiral corrections to the chiral-limit sum rule are obtained. Using PDG data, a recent parametrization of the pion-nucleon total cross sections in the resonance region given by the SAID group, as well as recent Roy-Steiner equation determinations of subthreshold amplitudes, threshold parameters, and correlated low-energy constants, the Adler-Weisberger sum rule is confronted with experimental data. With uncertainty estimates associated with the cross-section parametrization, the Goldberger-Treimann discrepancy, and the truncation of the sum rule at O (Mπ4) in the chiral expansion, this work finds gA=1.248 ±0.010 ±0.007 ±0.013 .

  7. Analysis of Chiral Carboxylic Acids in Meteorites

    Science.gov (United States)

    Burton, A. S.; Elsila, J. E.; Hein, J. E.; Aponte, J. C.; Parker, E. T.; Glavin, D. P.; Dworkin, J. P.

    2015-01-01

    Homochirality of amino acids in proteins and sugars in DNA and RNA is a critical feature of life on Earth. In the absence of a chiral driving force, however, reactions leading to the synthesis of amino acids and sugars result in racemic mixtures. It is currently unknown whether homochirality was necessary for the origins of life or if it was a product of early life. The observation of enantiomeric excesses of certain amino acids of extraterrestrial origins in meteorites provides evidence to support the hypothesis that there was a mechanism for the preferential synthesis or destruction of a particular amino acid enantiomer [e.g., 1-3]. The cause of the observed chiral excesses is un-clear, although at least in the case of the amino acid isovaline, the degree of aqueous alteration that occurred on the meteorite parent body is correlated to the isovaline L-enantiomeric excess [3, 4]. This suggests that chiral symmetry is broken and/or amplified within the meteorite parent bodies. Besides amino acids, there have been only a few reports of other meteoritic compounds found in enantiomeric excess: sugars and sugar acids [5, 6] and the hydroxy acid lactic acid [7]. Determining whether or not additional types of molecules in meteorites are also present in enantiomeric excesses of extraterrestrial information will provide insights into mechanisms for breaking chiral symmetry. Though the previous measurements (e.g., enantiomeric composition of lactic acid [7], and chiral carboxylic acids [8]) were made by gas chromatography-mass spectrometry, the potential for increased sensitivity of liquid chromatography-mass spectrometry (LC-MS) analyses is important because for many meteorite samples, only small sample masses are available for study. Furthermore, at least in the case of amino acids, many of the largest amino acid enantiomeric excesses were observed in samples that contained lower abundances (tens of ppb) of a given amino acid enantiomer. In the present work, we describe

  8. Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity.

    Science.gov (United States)

    Ogino, Yoshiyuki; Asahi, Toru

    2015-05-21

    In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug׳s efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies.

  9. Molecular-Level Design of Heterogeneous Chiral Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Zaera

    2012-03-21

    The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration

  10. Spin Chirality of Cu3 and V3 Nanomagnets. 1. Rotation Behavior of Vector Chirality, Scalar Chirality, and Magnetization in the Rotating Magnetic Field, Magnetochiral Correlations.

    Science.gov (United States)

    Belinsky, Moisey I

    2016-05-02

    The rotation behavior of the vector chirality κ, scalar chirality χ, and magnetization M in the rotating magnetic field H1 is considered for the V3 and Cu3 nanomagnets, in which the Dzialoshinsky-Moriya coupling is active. The polar rotation of the field H1 of the given strength H1 results in the energy spectrum characterized by different vector and scalar chiralities in the ground and excited states. The magnetochiral correlations between the vector and scalar chiralities, energy, and magnetization in the rotating field were considered. Under the uniform polar rotation of the field H1, the ground-state chirality vector κI performs sawtooth oscillations and the magnetization vector MI performs the sawtooth oscillating rotation that is accompanied by the correlated transformation of the scalar chirality χI. This demonstrates the magnetochiral effect of the joint rotation behavior and simultaneous frustrations of the spin chiralities and magnetization in the rotating field, which are governed by the correlation between the chiralities and magnetization.

  11. Chiral assembly of weakly curled hard rods: Effect of steric chirality and polarity

    Energy Technology Data Exchange (ETDEWEB)

    Wensink, H. H., E-mail: wensink@lps.u-psud.fr; Morales-Anda, L. [Laboratoire de Physique des Solides–UMR 8502, Université Paris-Sud & CNRS, 91405 Orsay (France)

    2015-10-14

    We theoretically investigate the pitch of lyotropic cholesteric phases composed of slender rods with steric chirality transmitted via a weak helical deformation of the backbone. In this limit, the model is amenable to analytical treatment within Onsager theory and a closed expression for the pitch versus concentration and helical shape can be derived. Within the same framework, we also briefly review the possibility of alternative types of chiral order, such as twist-bend or screw-like nematic phases, finding that cholesteric order dominates for weakly helical distortions. While long-ranged or “soft” chiral forces usually lead to a pitch decreasing linearly with concentration, steric chirality leads to a much steeper decrease of quadratic nature. This reveals a subtle link between the range of chiral intermolecular interaction and the pitch sensitivity with concentration. A much richer dependence on the thermodynamic state is revealed for polar helices where parallel and anti-parallel pair alignments along the local director are no longer equivalent. It is found that weak temperature variations may lead to dramatic changes in the pitch, despite the lyotropic nature of the assembly.

  12. Chiral metamaterial design using optimized pixelated inclusions with genetic algorithm

    Science.gov (United States)

    Akturk, Cemal; Karaaslan, Muharrem; Ozdemir, Ersin; Ozkaner, Vedat; Dincer, Furkan; Bakir, Mehmet; Ozer, Zafer

    2015-03-01

    Chiral metamaterials have been a research area for many researchers due to their polarization rotation properties on electromagnetic waves. However, most of the proposed chiral metamaterials are designed depending on experience or time-consuming inefficient simulations. A method is investigated for designing a chiral metamaterial with a strong and natural chirality admittance by optimizing a grid of metallic pixels through both sides of a dielectric sheet placed perpendicular to the incident wave by using a genetic algorithm (GA) technique based on finite element method solver. The effective medium parameters are obtained by using constitutive equations and S parameters. The proposed methodology is very efficient for designing a chiral metamaterial with the desired effective medium parameters. By using GA-based topology, it is proven that a chiral metamaterial can be designed and manufactured more easily and with a low cost.

  13. Detecting chirality in molecules by linearly polarized laser fields

    CERN Document Server

    Yachmenev, Andrey

    2016-01-01

    A new scheme for enantiomer differentiation of chiral molecules using a pair of linearly polarized intense ultrashort laser pulses with skewed mutual polarization is presented. The technique relies on the fact that the off-diagonal anisotropic contributions to the electric polarizability tensor for two enantiomers have different signs. Exploiting this property, we are able to excite a coherent unidirectional rotation of two enantiomers with a {\\pi} phase difference in the molecular electric dipole moment. The approach is robust and suitable for relatively high temperatures of molecular samples, making it applicable for selective chiral analysis of mixtures, and to chiral molecules with low barriers between enantiomers. As an illustration, we present nanosecond laser-driven dynamics of a tetratomic non-rigid chiral molecule with short-lived chirality. The ultrafast time scale of the proposed technique is well suited to study parity violation in molecular systems in short-lived chiral states.

  14. Manipulating the Lorentz force via the chirality of nanoparticles

    Science.gov (United States)

    Wang, Maoyan; Li, Hailong; Dong, Yuliang; Zhang, Xiaochuan; Du, Ming; Wang, Rui; Xu, Tong; Wu, Jian

    2016-12-01

    We demonstrate that a single plane wave pulls a chiral nanoparticle toward the light source. The nanoparticle exhibits optical gain in a particular wavelength region. The equivalence of the generalized and alternative expressions of the Lorentz force density relating to bound charges for chiral media is numerically validated. By considering the two-dimensional electromagnetic problem of incident plane waves normally impinged on active chiral cylinders, it is shown that the gradient force is mainly contributed by the bound electric and magnetic current densities of the cross-polarized waves. We also investigate how the medium parameters and impedance mismatch can be used to manipulate the pulling or pushing Lorentz forces between two chiral cylinders. This finding may provide a recipe to understand the light interaction with multiple chiral nanoparticles of arbitrary shapes (in general) with the aid of the numerical approach. It could be a promising avenue in controlling the optical micromanipulation for chiral nanoparticles with mirroring asymmetry.

  15. Development of chiral sulfoxide ligands for asymmetric catalysis.

    Science.gov (United States)

    Trost, Barry M; Rao, Meera

    2015-04-20

    Nitrogen-, phosphorus-, and oxygen-based ligands with chiral backbones have been the historic workhorses of asymmetric transition-metal-catalyzed reactions. On the contrary, sulfoxides containing chirality at the sulfur atom have mainly been used as chiral auxiliaries for diastereoselective reactions. Despite several distinct advantages over traditional ligand scaffolds, such as the proximity of the chiral information to the metal center and the ability to switch between S and O coordination, these compounds have only recently emerged as a versatile class of chiral ligands. In this Review, we detail the history of the development of chiral sulfoxide ligands for asymmetric catalysis. We also provide brief descriptions of metal-sulfoxide bonding and strategies for the synthesis of enantiopure sulfoxides. Finally, insights into the future development of this underutilized ligand class are discussed.

  16. Study of surface plasmon chirality induced by Archimedes' spiral grooves.

    Science.gov (United States)

    Ohno, Tomoki; Miyanishi, Shintaro

    2006-06-26

    A chirality of surface plasmons excited on a silver film with Archimedes' spiral grooves during incidence of a circularly polarized light is analytically and numerically studied by using the finite-difference time-domain (FDTD) modeling method. We found that the surface of a plasmon has selective chirality, which is given by the sum of the chiralities of the incident light and the spiral structure. The surface plasmons with the chirality lead to zero-order, first-order, and high-order evanescent Bessel beams with electric charge distributions on the film. This selectivity could be widely applied for chiral detection of the incident light and chiral excitation of several optical modes in nanophotonics.

  17. Microstructure Effects for Casimir Forces in Chiral Metamaterials

    CERN Document Server

    McCauley, Alexander P; Reid, M T Homer; Rodriguez, Alejandro W; Zhou, Jiangfeng; Rosa, F S S; Joannopoulos, John D; Dalvit, D A R; Soukoulis, Costas M; Johnson, Steven G

    2010-01-01

    We examine a recent prediction for the chirality-dependence of the Casimir force in chiral metamaterials by numerical computation of the forces between the exact microstructures, rather than homogeneous approximations. We compute the exact force for a chiral bent-cross pattern, as well as forces for an idealized "omega"-particle medium in the dilute approximation and identify the effects of structural inhomogeneity (i.e. proximity forces and anisotropy). We find that these microstructure effects dominate the force for separations where chirality was predicted to have a strong influence. To get observations of chirality free from microstructure effects, one must go to large separations where the effect of chirality is at most $\\sim10^{-4}$ of the total force.

  18. Designing large scale chiral metamaterials by nanosphere shadowing lithography

    Science.gov (United States)

    He, Yizhuo; Zhao, Yiping

    2016-09-01

    A scalable nanofabrication technique for chiral metamaterials is presented, which combines the dynamic shadowing growth and self-assembled nanosphere monolayers, and is also known as nanosphere shadowing lithography. We have developed two strategies based on nanosphere shadowing lithography to prepare chiral nanostructures. The first strategy is to create a quasi-three-dimensional single-layer fan-shaped chiral nanostructure on nanospheres with one plasmonic material. The second strategy is to create three-dimensional multi-layers helical nanostructures with one plasmonic material and one dielectric material. Both strategies can produce large-area chiral nanostructures with strong chiral optical response, which makes nanosphere shadowing lithography suitable for producing chiral metamaterial based devices such as an ultrathin narrow-band circular polarizer.

  19. Emergence of collective dynamical chirality for achiral active particles.

    Science.gov (United States)

    Jiang, Huijun; Ding, Huai; Pu, Mingfeng; Hou, Zhonghuai

    2017-01-25

    Emergence of collective dynamical chirality (CDC) at mesoscopic scales plays a key role in many formation processes of chiral structures in nature, which may also provide possible routines for people to fabricate complex chiral architectures. So far, most of the reported CDCs have been found in systems of active objects with individual structure chirality or/and dynamical chirality, and whether CDC can arise from simple and achiral units is still an attractive mystery. Here, we report a spontaneous formation of CDC in a system of both dynamically and structurally achiral particles motivated by active motion of cells adhered onto a substrate. Active motion, confinement and hydrodynamic interaction are found to be the three key factors. Detailed analysis shows that the system can support abundant collective dynamical behaviors, including rotating droplets, rotating bubbles, CDC oscillations, arrays of collective rotations, and interesting transitions such as chirality transition, structure transition and state reentrance.

  20. A molecular propeller effect for chiral separation and analysis

    Science.gov (United States)

    Clemens, Jonathon B.; Kibar, Osman; Chachisvilis, Mirianas

    2015-07-01

    Enantiomers share nearly identical physical properties but have different chiral geometries, making their identification and separation difficult. Here we show that when exposed to a rotating electric field, the left- and right-handed chiral molecules rotate with the field and act as microscopic propellers; moreover, owing to their opposite handedness, they propel along the axis of field rotation in opposite directions. We introduce a new molecular parameter called hydrodynamic chirality to characterize the coupling of rotational motion of a chiral molecule into its translational motion and quantify the direction and velocity of such motion. We demonstrate >80% enrichment level of counterpart enantiomers in solution without using chiral selectors or circularly polarized light. We expect our results to have an impact on multiple applications in drug discovery, analytical and chiral chemistry, including determination of absolute configuration, as well as in influencing the understanding of artificial and natural molecular systems where rotational motion of the molecules is involved.

  1. Chiral medium produced by parallel electric and magnetic fields

    CERN Document Server

    Ruggieri, Marco; Chernodub, Maxim

    2016-01-01

    We compute (pseudo)critical temperature, $T_c$, of chiral symmetry restoration for quark matter in the background of parallel electric and magnetic fields. This field configuration leads to the production of a chiral medium on a time scale $\\tau$, characterized by a nonvanishing value of the chiral density that equilibrates due to microscopic processes in the thermal bath. We estimate the relaxation time $\\tau$ to be about $\\approx 0.1-1$ fm/c around the chiral crossover; then we compute the effect of the fields and of the chiral medium on~$T_c$. We find $T_c$ to be lowered by the external fields in the chiral medium.

  2. Chiral spiral induced by a strong magnetic field

    CERN Document Server

    Abuki, H

    2016-01-01

    We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it totally washes the tricritical point out of the phase diagram, bringing the continent for the chiral spiral. This is the case no matter how small is the intensity of the magnetic field. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

  3. A primer for Chiral Perturbative Theory

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, Stefan [Mainz Univ. (Germany). Inst. fuer Kernphysik; Schindler, Matthias R. [South Carolina Univ., Columbia, SC (United States). Dept. of Physics; George Washington Univ., Washington, DC (United States). Dept. of Physics

    2012-07-01

    Chiral Perturbation Theory, as effective field theory, is a commonly accepted and well established working tool, approximating quantum chromodynamics at energies well below typical hadron masses. This volume, based on a number of lectures and supplemented with additional material, provides a pedagogical introduction for graduate students and newcomers entering the field from related areas of nuclear and particle physics. Starting with the the Lagrangian of the strong interactions and general symmetry principles, the basic concepts of Chiral Perturbation Theory in the mesonic and baryonic sectors are developed. The application of these concepts is then illustrated with a number of examples. A large number of exercises (81, with complete solutions) are included to familiarize the reader with helpful calculational techniques. (orig.)

  4. Oscillating Chiral Tensor Spectrum from Axionic Inflation

    CERN Document Server

    Obata, Ippei

    2016-01-01

    We study the axionic inflation with a modulated potential and examine if the primordial tensor power spectrum exhibits oscillatory feature, which is testable with future space-based gravitational wave experiments such as DECIGO and BBO. In the case of the single-field axion monodromy inflation, it turns out that it is difficult to detect the oscillation in the spectrum due to suppression of the sub-Planckian decay constant of axion. On the other hand, in the case of aligned chromo-natural inflation where the axion is coupled to a SU(2) gauge field, it turns out that the sizable oscillation in the tensor spectrum can occur due to the enhancement of chiral gravitational waves sourced by the gauge field. We expect that this feature will be a new probe to axion phenomenologies in early universe through the chiral gravitational waves.

  5. Chiral fermions in asymptotically safe quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Meibohm, J. [Gothenburg University, Department of Physics, Goeteborg (Sweden); Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); Pawlowski, J.M. [Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung mbH, ExtreMe Matter Institute EMMI, Darmstadt (Germany)

    2016-05-15

    We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works (Christiansen et al., Phys Rev D 92:121501, 2015; Meibohm et al., Phys Rev D 93:084035, 2016), concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models. We find strong evidence that this feature is independent of the number of fermion fields. This finding suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions. (orig.)

  6. Lattice Theories with Nonlinearly Realized Chiral Symmetry

    CERN Document Server

    Chandrasekharan, S; Steffen, F D; Wiese, U J

    2003-01-01

    We present the lattice formulation of effective Lagrangians in which chiral symmetry is realized nonlinearly on the fermion fields. In this framework both the Wilson term removing unphysical doubler fermions and the fermion mass term do not break chiral symmetry. Our lattice formulation allows us to address non-perturbative questions in effective theories of baryons interacting with pions and in models involving constitutent quarks interacting with pions and gluons. With the presented methods, a system containing a non-zero density of static baryons interacting with pions can be studied on the lattice without encountering a complex action problem. This might lead to new insights into the phase diagram of strongly interacting matter at non-zero chemical potential.

  7. A primer for chiral perturbation theory

    CERN Document Server

    Scherer, Stefan

    2012-01-01

    Chiral Perturbation Theory, as effective field theory, is a commonly accepted and well established working tool, approximating quantum chromodynamics at energies well below typical hadron masses. This volume, based on a number of lectures and supplemented with additional material, provides a pedagogical introduction for graduate students and newcomers entering the field from related areas of nuclear and particle physics. Starting with the the Lagrangian of the strong interactions and general symmetry principles, the basic concepts of Chiral Perturbation Theory in the mesonic and baryonic sectors are developed. The application of these concepts is then illustrated with a number of examples. A large number of exercises (81, with complete solutions) are included to familiarize the reader with helpful calculational techniques.

  8. Chiral discrimination in biomimetic systems: Phenylalanine

    Indian Academy of Sciences (India)

    K Thirumoorthy; K Soni; T Arun; N Nandi

    2007-09-01

    Chiral discrimination and recognition is important in peptide biosynthesis, amino acid synthesis and drug designing. Detailed structural information is available about the peptide synthesis in ribosome. However, no detailed study is available about the discrimination in peptide synthesis. We study the conformational energy variation of neutral methoxy phenyl alanine molecule as a function of its different dihedral angle to locate the minimum energy conformation using quantum chemical theory. We compared the intermolecular energy surfaces of phenyl alanine molecule in its neutral and zwitterionic state using quantum chemical theory as a function of distance and mutual orientation. The energy surfaces are studied with rigid geometry by varying the distance and orientation. The potential energy surfaces of - and - pairs are found to be dissimilar and reflect the underlying chirality of the homochiral pair and racemic nature of the heterochiral pair. The intermolecular energy surface of homochiral pair is more favourable than the corresponding energy surface of heterochiral pair.

  9. Chiral perturbation theory with tensor sources

    Energy Technology Data Exchange (ETDEWEB)

    Cata, Oscar; Cata, Oscar; Mateu, Vicent

    2007-05-21

    We construct the most general chirally-invariant Lagrangian for mesons in the presence of external sources coupled to the tensor current \\bar psi sigma_mu nu psi. In order to have only even terms in the chiral expansion, we consider the new source of O(p2). With this choice, we build the even-parity effective Lagrangian up to the p6-order (NLO). While there are only 4 new terms at the p4-order, at p6-order we find 78 terms for n_f=2 and 113 terms for n_f=3. We provide a detailed discussion on the different mechanisms that ensure that our final set of operators is complete and non-redundant. We also examine the odd-parity sector, to conclude that the first operators appear at the p8-order (NNLO).

  10. Random Matrices and Chiral Symmetry in QCD

    CERN Document Server

    Janik, R A; Papp, G; Zahed, I; Janik, Romuald A.; Nowak, Maciej A.; Papp, Gabor; Zahed, Ismail

    1998-01-01

    In this talk we review some recent results from random matrix models as applied to some non-perturbative issues in QCD. All of the issues we will discuss touched upon the important phenomenon related to the spontaneous breaking of chiral symmetry. The afore mentioned insights are: 1. Spontaneous breakdown of chiral symmetry and disorder. 2. Universal microscopic properties of the eigenvalues of the Dirac operator in the vacuum. 3. Universal microscopic properties of the eigenvalues of the Dirac operator in matter. 4. Structural changes of the Dirac spectrum - finite temperature. 5. Structural changes of the Dirac spectrum - finite baryonic density - ``phony vacua'' 6. Structural changes of the Dirac spectrum - finite baryonic density - ``true vacua'' . 7. Phase diagram. 8. Critical parameters. 9. Critical exponents. 10. $U(1)_A$ problem. 11. Screening of the pseudoscalar susceptibility. 12. Strong CP violation (finite $\\theta$).

  11. Chiral fermions in asymptotically safe quantum gravity

    CERN Document Server

    Meibohm, Jan

    2016-01-01

    We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck-scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works \\cite{Christiansen:2015rva, Meibohm:2015twa}, concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models, regardless of the number of fermion flavours. This suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions.

  12. Chiral patterning in Paenibacillus colonies under stress

    Science.gov (United States)

    Levine, Herbert

    2012-02-01

    One of the most striking examples of bacterial colony patterning occurs in the C-morphotype of Paenibacillus strains. Here, macroscopic chirality results from the interaction of local liquid-crystal ordering of the long bacterial cells with the self-propelled motility driven by the non-reflection-symmetric flagella. This talk will review some of the original experimental data from the Ben-Jacob lab as well as recent insight obtained via genomics. I will then discuss attempts to model and simulate the chiral patterns via solving reaction-diffusion equations on random lattices. At the end, I will introduce the challenges still to be faced in understanding transitions between these patterns and more common branching structures

  13. Helical chirality induction of expanded porphyrin analogues

    Indian Academy of Sciences (India)

    Jun-Ichiro Setsune

    2012-11-01

    Expanded porphyrin analogues with unique figure-eight conformation were prepared by way of useful pyrrole intermediates such as bis(azafulvene)s and 2-borylpyrrole. Supramolecular chirogenesis of cyclooctapyrrole O1 with 32-cycloconjugation was successfully applied to determine absolute configuration of chiral carboxylic acids. Dinuclear CuII complex of cyclooctapyrrole O2 with interrupted -conjugation was resolved by HPLC into enantiomers and their helical handedness was determined by theoretical simulation of their CD spectral pattern. Enantioselective induction of helicity in the metal helicate formation in the presence of a chiral promoter was demonstrated by using ()-(+)-1-(1-phenyl)ethylamine that favoured , helicity. Dinuclear CoII complexes of cyclotetrapyrroletetrapyridine O3 were found to be substitution labile and pick up amino acid anions in water. Those amino acid complexes of O3Co2 were rendered to adopt a particular unidirectional helical conformation preferentially depending on the ligated amino acid anion.

  14. Optical Tractor Beam with Chiral Light

    CERN Document Server

    Fernandes, David E

    2015-01-01

    We suggest a novel mechanism to induce the motion of a chiral material body towards an optical source. Our solution is based on the interference between a chiral light beam and its reflection on an opaque mirror. Surprisingly, it is theoretically shown that the electromagnetic response of the material may be tailored in such a way that independent of the specific body location with the respect to the mirror, it is always pushed upstream against the photon flow associated with the incoming wave. Moreover, it is proven that by controlling the handedness of the incoming light it may be possible to harness the sign of the optical force, switching from a pulling force to a pushing force.

  15. Bootstrapping ${\\mathcal N}=2$ chiral correlators

    CERN Document Server

    Lemos, Madalena

    2016-01-01

    We apply the numerical bootstrap program to chiral operators in four-dimensional ${\\mathcal N}=2$ SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of ${\\mathcal N}=2$ SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  16. A Nonperturbative Regulator for Chiral Gauge Theories

    CERN Document Server

    Grabowska, Dorota M

    2015-01-01

    We propose a nonperturbative gauge invariant regulator for $d$-dimensional chiral gauge theories on the lattice. The method involves simulating domain wall fermions in $d+1$ dimensions with quantum gauge fields that reside on one $d$-dimensional surface and are extended into the bulk via gradient flow. The result is a theory of gauged fermions plus mirror fermions, where the mirror fermions couple to the gauge fields via a form factor that becomes exponentially soft with the separation between domain walls. The resultant theory has a local $d$-dimensional interpretation if and only if the chiral fermion representation is anomaly free. A physical realization of this construction leads to mirror fermions in the Standard Model with soft form factors for gauge fields and gravity. These mirror particles could evade detection except by sensitive probes at extremely low energy, and yet still affect vacuum topology, and could gravitate differently than conventional matter.

  17. New approaches in sensitive chiral CE.

    Science.gov (United States)

    Sánchez-Hernández, Laura; Guijarro-Diez, Miguel; Marina, María Luisa; Crego, Antonio L

    2014-01-01

    CE has shown to have a big potential for chiral separations, with advantages such as high efficiency, high resolution, and low sample and reagents consumption. Nevertheless, when UV detection is employed, CE has some drawbacks, especially the low sensitivity obtained due to the short optical path length. Notwithstanding, sensitivity improvements can be achieved when different approaches are employed, such as sample treatment strategies (off-line or on-line), in-capillary sample preconcentration techniques, and/or alternative detection systems to UV-Vis (such as fluorescence, conductimetry, electrochemiluminiscence, MS, etc.). This article reviews the most recent methodological and instrumental advances reported from June 2011 to May 2013 for enhancing the sensitivity in chiral analysis by CE. The sensitivity achieved for the enantioseparated analytes and the applications carried out using the developed methodologies are also summarized.

  18. Active control of chirality in nonlinear metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yu; Chai, Zhen; Yang, Hong [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Hu, Xiaoyong, E-mail: xiaoyonghu@pku.edu.cn; Gong, Qihuang [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)

    2015-03-02

    An all-optical tunabe chirality is realized in a photonic metamaterial, the metamolecule of which consists of a nonlinear nano-Au:polycrystalline indium-tin oxide layer sandwiched between two L-shaped gold nano-antennas twisted 90° with each other. The maximum circular dichroism reached 30%. Under excitation of a 40 kW/cm{sup 2} weak pump light, the peak in the circular dichroism shifts 45 nm in the short-wavelength direction. An ultrafast response time of 35 ps is maintained. This work not only opens up the possibility for the realization of ultralow-power and ultrafast all-optical tunable chirality but also offers a way to construct ultrahigh-speed on-chip biochemical sensors.

  19. Chiral Four-Dimensional Heterotic Covariant Lattices

    CERN Document Server

    Beye, Florian

    2014-01-01

    In the covariant lattice formalism, chiral four-dimensional heterotic string vacua are obtained from certain even self-dual lattices which completely decompose into a left-mover and a right-mover lattice. The main purpose of this work is to classify all right-mover lattices that can appear in such a chiral model, and to study the corresponding left-mover lattices using the theory of lattice genera. In particular, the Smith-Minkowski-Siegel mass formula is employed to calculate a lower bound on the number of left-mover lattices. Also, the known relationship between asymmetric orbifolds and covariant lattices is considered in the context of our classification.

  20. Chiral transition and deconfinement in QCD

    CERN Document Server

    D'Elia, M; Pica, C

    2006-01-01

    The study of QCD with two light dynamical fermions is of fundamental importance to understand the mechanism of color confinement. We present results of a numerical investigation on the order of the chiral phase transition with $N_f = 2$ by use of a novel strategy in finite size scaling analysis. We compare the critical behaviour of the specific heat, of the chiral susceptibility and of the equation of state with the possible critical behaviours. A second order transition in the O(4) and O(2) universality classes are excluded by our data and substantial evidence emerges for a first order transition. Like in most of previous works we have used the standard staggered action with $L_t = 4$: possible scaling violations and the need for further studies are discussed.

  1. Magnetic rotation and chiral symmetry breaking

    Indian Academy of Sciences (India)

    Ashok Kumar Jain; Amita

    2001-08-01

    The deformed mean field of nuclei exhibits various geometrical and dynamical symmetries which manifest themselves as various types of rotational and decay patterns. Most of the symmetry operations considered so far have been defined for a situation wherein the angular momentum coincides with one of the principal axes and the principal axis cranking may be invoked. New possibilities arise with the observation of rotational features in weakly deformed nuclei and now interpreted as magnetic rotational bands. More than 120 MR bands have now been identified by filtering the existing data. We present a brief overview of these bands. The total angular momentum vector in such bands is tilted away from the principal axes. Such a situation gives rise to several new possibilities including breaking of chiral symmetry as discussed recently by Frauendorf. We present the outcome of such symmetries and their possible experimental verification. Some possible examples of chiral bands are presented.

  2. Chiral extrapolation of nucleon magnetic form factors

    Energy Technology Data Exchange (ETDEWEB)

    P. Wang; D. Leinweber; A. W. Thomas; R.Young

    2007-04-01

    The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer (Q{sup 2}), a separate extrapolation to the physical pion mass is carried out as a function of m{sub {pi}} alone. Because of the large values of Q{sup 2} involved, the role of the pion form factor in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of Q{sup 2} and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.

  3. Chiral Magnetic Effect Task Force Report

    CERN Document Server

    Skokov, Vladimir; Koch, Volker; Schlichting, Soeren; Thomas, Jim; Voloshin, Sergei; Wang, Gang; Yee, Ho-Ung

    2016-01-01

    In this report, we briefly examine the current status of the study of the chiral magnetic effect including theory and experimental progress. We recommend future strategies for resolving uncertainties in interpretation including recommendations for theoretical work, recommendations for measurements based on data collected in the past five years, and recommendations for beam use in the coming years of RHIC. We have specifically investigated the case for colliding nuclear isobars (nuclei with the same mass but different charge) and find the case compelling. We recommend that a program of nuclear isobar collisions to isolate the chiral magnetic effect from background sources be placed as a high priority item in the strategy for completing the RHIC mission.

  4. Simultaneous Chiral SeparationUsing a Combinatorial Molecular Imprinting Phase

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Molecular imprinting chiral stationary phase against Cbz-L-Serine (Cbz-L-Ser) and Cbz-L-Alaine (Cbz-L-Ala) were prepared utilizing acrylamide + 2-vinylpyridine as combined basic functional monomers.Cross-selectivity was used to obtain simultaneous chiral separations of Cbz-DL-Ser and Cbz-DL-Ala by connecting two columns packed with Cbz-L-Ser and Cbz-L-Ala imprinted chiral stationary phase, respectively.

  5. Chiral condensate, susceptibilities, critical coupling and indices in QED$_{4}$

    CERN Document Server

    Azcoiti, V; Galante, A; Grillo, A F; Laliena, V; Piedrafita, C E

    1995-01-01

    We measure chiral susceptibilities in the Coulomb phase of noncompact QED_4 in 8^4, 10^4 and 12^4 lattices. The MFA approach allows simulations in the chiral limit which are therefore free from arbitrary mass extrapolations. Using the critical couplings extracted from these calculations, we study the critical behaviour of the chiral condensate, which we find in disagreement with the predictions of logarithmically improved scalar Mean Field theory.

  6. Microstructure Effects for Casimir Forces in Chiral Metamaterials

    OpenAIRE

    McCauley, Alexander P.; Zhao, Rongkuo; Reid, M. T. Homer; Rodriguez, Alejandro W.; Zhou, Jiangfeng; Rosa, F. S. S.; Joannopoulos, John D; Dalvit, D. A. R.; Soukoulis, Costas M.; Johnson, Steven G.

    2010-01-01

    We examine a recent prediction for the chirality-dependence of the Casimir force in chiral metamaterials by numerical computation of the forces between the exact microstructures, rather than homogeneous approximations. We compute the exact force for a chiral bent-cross pattern, as well as forces for an idealized "omega"-particle medium in the dilute approximation and identify the effects of structural inhomogeneity (i.e. proximity forces and anisotropy). We find that these microstructure effe...

  7. First molecules, biological chirality, origin(s) of life.

    Science.gov (United States)

    Caglioti, Luciano; Micskei, Károly; Pályi, Gyula

    2011-01-01

    Origin(s) of biological chirality appear(s) to be intimately connected to origin(s) of life. Prebiotic evolution toward these important turning points can be traced back to single chiral molecules. These can be small (monomeric) units as amino acids or monosaccharides or oligomers as oligo-RNA type molecules. Earlier speculations about these two kinds of entries to biological chirality are critically reviewed.

  8. Chirality and anaesthetic drugs: A review and an update

    OpenAIRE

    Sukanya Mitra; Puneet Chopra

    2011-01-01

    Many molecules can exist as right-handed and left-handed forms that are non-superimposable mirror images of each other. They are known as enantiomers or substances of opposite shape. Such compounds are also said to be chiral (Greek chiros meaning ‘hand’). Such chiral molecules are of great relevance to anaesthetic theory and practice. This review summarizes the basic concepts, pharmacokinetic and pharmacodynamic aspects of chirality, and some specific examples of their application in anaesthe...

  9. Laminar and Turbulent Dynamos in Chiral Magnetohydrodynamics. I. Theory

    Science.gov (United States)

    Rogachevskii, Igor; Ruchayskiy, Oleg; Boyarsky, Alexey; Fröhlich, Jürg; Kleeorin, Nathan; Brandenburg, Axel; Schober, Jennifer

    2017-09-01

    The magnetohydrodynamic (MHD) description of plasmas with relativistic particles necessarily includes an additional new field, the chiral chemical potential associated with the axial charge (i.e., the number difference between right- and left-handed relativistic fermions). This chiral chemical potential gives rise to a contribution to the electric current density of the plasma (chiral magnetic effect). We present a self-consistent treatment of the chiral MHD equations, which include the back-reaction of the magnetic field on a chiral chemical potential and its interaction with the plasma velocity field. A number of novel phenomena are exhibited. First, we show that the chiral magnetic effect decreases the frequency of the Alfvén wave for incompressible flows, increases the frequencies of the Alfvén wave and of the fast magnetosonic wave for compressible flows, and decreases the frequency of the slow magnetosonic wave. Second, we show that, in addition to the well-known laminar chiral dynamo effect, which is not related to fluid motions, there is a dynamo caused by the joint action of velocity shear and chiral magnetic effect. In the presence of turbulence with vanishing mean kinetic helicity, the derived mean-field chiral MHD equations describe turbulent large-scale dynamos caused by the chiral alpha effect, which is dominant for large fluid and magnetic Reynolds numbers. The chiral alpha effect is due to an interaction of the chiral magnetic effect and fluctuations of the small-scale current produced by tangling magnetic fluctuations (which are generated by tangling of the large-scale magnetic field by sheared velocity fluctuations). These dynamo effects may have interesting consequences in the dynamics of the early universe, neutron stars, and the quark–gluon plasma.

  10. Chiral closed strings: four massless states scattering amplitude

    Science.gov (United States)

    Leite, Marcelo M.; Siegel, Warren

    2017-01-01

    We compute the scattering amplitudes of four massless states for chiral (closed) bosonic and type II superstrings using the Kawai-Lewellen-Tye ( KLT ) factorization method. The amplitude in the chiral bosonic case is identical to a field theory amplitude corresponding to the spin-2 tachyon, massless gravitational sector and massive spin-2 tardyon states of the spectrum. Chiral type II superstrings amplitude only possess poles associated with the massless gravitational sector. We briefly discuss the extension of the calculation to heterotic superstrings.

  11. Chiral Closed strings: Four massless states scattering amplitude

    CERN Document Server

    Leite, Marcelo M

    2016-01-01

    We compute the scattering amplitudes of four massless states for chiral (closed) bosonic and type II superstrings using the Kawai-Lewellen-Tye ($KLT$) factorization method. The amplitude in the chiral bosonic case is identical to a field theory amplitude corresponding to the spin-$2$ tachyon, massless gravitational sector and massive spin-2 tardyon states of the spectrum. Chiral type II superstrings amplitude only possess poles associated with the massless gravitational sector. We briefly discuss the extension of the calculation to heterotic superstrings.

  12. Nanoconfinement-Induced Structures in Chiral Liquid Crystals

    OpenAIRE

    2013-01-01

    We employ Monte Carlo simulations in a specialized isothermal-isobaric and in the grand canonical ensemble to study structure formation in chiral liquid crystals as a function of molecular chirality. Our model potential consists of a simple Lennard-Jones potential, where the attractive contribution has been modified to represent the orientation dependence of the interaction between a pair of chiral liquid-crystal molecules. The liquid crystal is confined between a pair of planar and atomicall...

  13. Chiral deformations of conformal field theories

    Science.gov (United States)

    Dijkgraaf, Robbert

    1997-02-01

    We study general perturbations of two-dimensional conformal field theories by holomorphic fields. It is shown that the genus one partition function is controlled by a contact term (pre-Lie) algebra given in terms of the operator product expansion. These models have applications to vertex operator algebras, two-dimensional QCD, topological strings, holomorphic anomaly equations and modular properties of generalized characters of chiral algebras such as the W1+∞ algebra, that is treated in detail.

  14. Chiral Deformations of Conformal Field Theories

    CERN Document Server

    Dijkgraaf, R

    1996-01-01

    We study general perturbations of two-dimensional conformal field theories by holomorphic fields. It is shown that the genus one partition function is controlled by a contact term (pre-Lie) algebra given in terms of the operator product expansion. These models have applications to vertex operator algebras, two-dimensional QCD, topological strings, holomorphic anomaly equations and modular properties of generalized characters of chiral algebras such as the $W_{1+\\infty}$ algebra, that is treated in detail.

  15. Chiral deformations of conformal field theories

    Energy Technology Data Exchange (ETDEWEB)

    Dijkgraaf, R. [Amsterdam Univ. (Netherlands). Dept. of Math.

    1997-06-02

    We study general perturbations of two-dimensional conformal field theories by holomorphic fields. It is shown that the genus one partition function is controlled by a contact term (pre-Lie) algebra given in terms of the operator product expansion. These models have applications to vertex operator algebras, two-dimensional QCD, topological strings, holomorphic anomaly equations and modular properties of generalized characters of chiral algebras such as the W{sub 1+{infinity}} algebra, that is treated in detail. (orig.).

  16. Chiral Deformations of Conformal Field Theories

    OpenAIRE

    Dijkgraaf, R.

    1996-01-01

    We study general perturbations of two-dimensional conformal field theories by holomorphic fields. It is shown that the genus one partition function is controlled by a contact term (pre-Lie) algebra given in terms of the operator product expansion. These models have applications to vertex operator algebras, two-dimensional QCD, topological strings, holomorphic anomaly equations and modular properties of generalized characters of chiral algebras such as the $W_{1+\\infty}$ algebra, that is treat...

  17. Chiral unitary theory: Application to nuclear problems

    Indian Academy of Sciences (India)

    E Oset; D Cabrera; H C Chiang; C Garcia Recio; S Hirenzaki; S S Kamalov; J Nieves; Y Okumura; A Ramos; H Toki; M J Vicente Vacas

    2001-08-01

    In this talk we briefly describe some basic elements of chiral perturbation theory, , and how the implementation of unitarity and other novel elements lead to a better expansion of the -matrix for meson–meson and meson–baryon interactions. Applications are then done to the interaction in nuclear matter in the scalar and vector channels, antikaons in nuclei and - atoms, and how the meson properties are changed in a nuclear medium.

  18. Hyperbolic Weyl Point in Reciprocal Chiral Metamaterials.

    Science.gov (United States)

    Xiao, Meng; Lin, Qian; Fan, Shanhui

    2016-07-29

    We report the existence of Weyl points in a class of noncentral symmetric metamaterials, which has time reversal symmetry, but does not have inversion symmetry due to chiral coupling between electric and magnetic fields. This class of metamaterial exhibits either type-I or type-II Weyl points depending on its nonlocal response. We also provide a physical realization of such metamaterial consisting of an array of metal wires in the shape of elliptical helices which exhibits type-II Weyl points.

  19. Chiral benzimidazoles as hydrogen bonding organocatalysts

    OpenAIRE

    Nájera Domingo, Carmen; Yus Astiz, Miguel

    2015-01-01

    Several bifunctional organocatalysts bearing the benzimidazole unit have been designed in order to act as bifunctional systems by hydrogen bonding. Chiral 2-aminobenzimidazoles are conformational rigid guanidines able to catalyze enantioselectively Michael reaction, direct SN1 of alcohols, and aldol reactions. Some of these organocatalysts can be easily recovered by simple isolation methods and reused without loss of catalytic activity. Related (2-aminoalkyl)benzimidazoles have been used as c...

  20. Wave propagation retrieval method for chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2010-01-01

    In this paper we present the wave propagation method for the retrieving of effective properties of media with circularly polarized eigenwaves, in particularly for chiral metamaterials. The method is applied for thick slabs and provides bulk effective parameters. Its strong sides are the absence...... of artificial branches of the refractive index and simplicity in implementation. We prove the validity of the method on three case studies of homogeneous magnetized plasma, bi-cross and U-shaped metamaterials....

  1. Stern-Gerlach effect goes chiral

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states (Phys. Rev. Lett. 99 130403).

  2. Chiral Symmetry restoration from the hadronic regime

    CERN Document Server

    Nicola, Angel Gomez; Morales, John; de Elvira, Jacobo Ruiz; Andres, Ricardo Torres

    2016-01-01

    We discuss recent advances on QCD chiral symmetry restoration at finite temperature, within the theoretical framework of Effective Theories. $U(3)$ Ward Identities are derived between pseudoscalar susceptibilities and quark condensates, allowing to explain the behaviour of lattice meson screening masses. Unitarized interactions and the generated $f_0(500)$ thermal state are showed to play an essential role in the description of the transition through the scalar susceptibility

  3. Chiral Biomarkers and Microfossils in Carbonaceous Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-01-01

    Homochirality of the biomolecules (D-sugars of DNA and RNA and L-amino acids of proteins) is a fundamental property of all life on Earth. Abiotic mechanisms yield racemic mixtures (D/L=1) of chiral molecules and after the death of an organism, the enantiopure chiral biomolecules slowly racemize. Several independent investigators have now established that the amino acids present in CI1 and CM2 carbonaceous meteorites have a moderate to strong excess of the L-enantiomer. Stable isotope data have established that these amino acids are both indigenous and extraterrestrial. Carbonaceous meteorites also contain many other strong chemical biomarkers including purines and pyrimidines (nitrogen heterocycles of nucleic acids); pristine and phytane (components of the chlorophyll pigment) and morphological biomarkers (microfossils of filamentous cyanobacteria). Energy dispersive X-ray Spectroscopy (EDS) analysis reveals that nitrogen is below the detectability level in most of the meteorite filaments as well as in Cambrian Trilobites and filaments of 2.7 Gya Archaean cyanobacteria from Karelia. The deficiency of nitrogen in the filaments and the total absence of sugars, of twelve of the life-critical protein amino acids, and two of the nucleobases of DNA and RNA provide clear and convincing evidence that these filaments are not modern biological contaminants. This paper reviews the chiral, chemical biomarkers morphological biomarkers and microfossils in carbonaceous meteorites. This paper reviews chiral and morphological biomarkers and discusses the missing nitrogen, sugars, protein amino acids, and nucleobases as ?bio-discriminators? that exclude modern biological contaminants as a possible explanation for the permineralized cyanobacterial filaments found in the meteorites.

  4. Chiral biomarkers and microfossils in carbonaceous meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-09-01

    Homochirality of the biomolecules (D-sugars of DNA and RNA and L-amino acids of proteins) is a fundamental property of all life on Earth. Abiotic mechanisms yield racemic mixtures (D/L=1) of chiral molecules and after the death of an organism, the enantiopure chiral biomolecules slowly racemize. Several independent investigators have now established that the amino acids present in CI1 and CM2 carbonaceous meteorites have a moderate to strong excess of the L-enantiomer. Stable isotope data have established that these amino acids are both indigenous and extraterrestrial. Carbonaceous meteorites also contain many other strong chemical biomarkers including purines and pyrimidines (nitrogen heterocycles of nucleic acids); pristine and phytane (components of the chlorophyll pigment) and morphological biomarkers (microfossils of filamentous cyanobacteria). Energy dispersive X-ray Spectroscopy (EDS) analysis reveals that nitrogen is below the detectability level in most of the meteorite filaments as well as in Cambrian Trilobites and filaments of 2.7 Gya Archaean cyanobacteria from Karelia. The deficiency of nitrogen in the filaments and the total absence of sugars, of twelve of the life-critical protein amino acids, and two of the nucleobases of DNA and RNA provide clear and convincing evidence that these filaments are not modern biological contaminants. This paper reviews the chiral, chemical biomarkers morphological biomarkers and microfossils in carbonaceous meteorites. This paper reviews chiral and morphological biomarkers and discusses the missing nitrogen, sugars, protein amino acids, and nucleobases as "bio-discriminators" that exclude modern biological contaminants as a possible explanation for the permineralized cyanobacterial filaments found in the meteorites.

  5. Anomalous CMB polarization and gravitational chirality

    OpenAIRE

    Contaldi, Carlo R.; Magueijo, Joao; Smolin, Lee

    2008-01-01

    We consider the possibility that gravity breaks parity, with left and right handed gravitons coupling to matter with a different Newton's constant and show that this would affect their zero-point vacuum fluctuations during inflation. Should there be a cosmic background of gravity waves, the effect would translate into anomalous CMB polarization. Non-vanishing TB (and EB) polarization components emerge, revealing interesting experimental targets. Indeed if reasonable chirality is present a TB ...

  6. Synthesis of Resins with Chiral Salen Complexes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ The enormous growth in the use of polymer resin supports in solid phase combinatorial synthesis, and related methodologies, has re-stimulated interest in the area of polymer-supported transition metal complex catalyst .The recently developed chiral salen-based for the enantioselective ring opening of meso epoxides and kinetic resolution of terminal epoxides are appealing candidates for immobilization on solid support. The catalysts are reading prepare from inexpensive components, and are amenable to modification for attachment to a solid support.

  7. Chiral random matrix theory for staggered fermions

    CERN Document Server

    Osborn, James C

    2012-01-01

    We present a completed random matrix theory for staggered fermions which incorporates all taste symmetry breaking terms at their leading order from the staggered chiral Lagrangian. This is an extension of previous work which only included some of the taste breaking terms. We will also discuss the effects of taste symmetry breaking on the eigenvalues in the weak and strong taste breaking limits, and compare with some results from lattice simulations.

  8. What flows in the chirally anomalous transport?

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Kenji

    2016-12-15

    A combination of the magnetic field and the quantum anomaly leads to transport phenomena of chiral fermions. On the microscopic level, however, what really flows is a non-trivial question. I propose an answer to this question; the particle production affected by the magnetic field and the quantum anomaly has an anisotropic distribution in momentum space, which should be realized in the heavy-ion collision by a fast process occurring on top of color flux tubes in the glasma.

  9. Circular Intensity Differential Scattering of chiral molecules

    Energy Technology Data Exchange (ETDEWEB)

    Bustamante, C.J.

    1980-12-01

    In this thesis a theory of the Circular Intensity Differential Scattering (CIDS) of chiral molecules as modelled by a helix oriented with respect to the direction of incidence of light is presented. It is shown that a necessary condition for the existence of CIDS is the presence of an asymmetric polarizability in the scatterer. The polarizability of the scatterer is assumed generally complex, so that both refractive and absorptive phenomena are taken into account.

  10. Chiral quark model with relativistic kinematics

    CERN Document Server

    Garcilazo, H

    2003-01-01

    The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.

  11. Concise theory of chiral lipid membranes

    CERN Document Server

    Tu, Z C

    2007-01-01

    A theory of chiral lipid membranes is proposed on the basis of a concise free energy density which includes the contributions of the bending and the surface tension of membranes, as well as the chirality and orientational variation of tilting molecules. This theory is consistent with the previous experiments [J.M. Schnur \\textit{et al.}, Science \\textbf{264}, 945 (1994); M.S. Spector \\textit{et al.}, Langmuir \\textbf{14}, 3493 (1998); Y. Zhao, \\textit{et al.}, Proc. Natl. Acad. Sci. USA \\textbf{102}, 7438 (2005)] on self-assembled chiral lipid membranes of DC$_{8,9}$PC. A torus with the ratio between its two generated radii larger than $\\sqrt{2}$ is predicted from the Euler-Lagrange equations. It is found that tubules with helically modulated tilting state are not admitted by the Euler-Lagrange equations, and that they are less energetically favorable than helical ripples in tubules. The pitch angles of helical ripples are theoretically estimated to be about 0$^\\circ$ and 35$^\\circ$, which are close to the mo...

  12. Chiral analysis of baryon form factors

    Energy Technology Data Exchange (ETDEWEB)

    Gail, T.A.

    2007-11-08

    This work presents an extensive theoretical investigation of the structure of the nucleon within the standard model of elementary particle physics. In particular, the long range contributions to a number of various form factors parametrizing the interactions of the nucleon with an electromagnetic probe are calculated. The theoretical framework for those calculations is chiral perturbation theory, the exact low energy limit of Quantum Chromo Dynamics, which describes such long range contributions in terms of a pion-cloud. In this theory, a nonrelativistic leading one loop order calculation of the form factors parametrizing the vector transition of a nucleon to its lowest lying resonance, the {delta}, a covariant calculation of the isovector and isoscalar vector form factors of the nucleon at next to leading one loop order and a covariant calculation of the isoscalar and isovector generalized vector form factors of the nucleon at leading one loop order are performed. In order to perform consistent loop calculations in the covariant formulation of chiral perturbation theory an appropriate renormalization scheme is defined in this work. All theoretical predictions are compared to phenomenology and results from lattice QCD simulations. These comparisons allow for a determination of the low energy constants of the theory. Furthermore, the possibility of chiral extrapolation, i.e. the extrapolation of lattice data from simulations at large pion masses down to the small physical pion mass is studied in detail. Statistical as well as systematic uncertainties are estimated for all results throughout this work. (orig.)

  13. Chiral discrimination in optical trapping and manipulation

    Science.gov (United States)

    Bradshaw, David S.; Andrews, David L.

    2014-10-01

    When circularly polarized light interacts with chiral molecules or nanoscale particles powerful symmetry principles determine the possibility of achieving chiral discrimination, and the detailed form of electrodynamic mechanisms dictate the types of interaction that can be involved. The optical trapping of molecules and nanoscale particles can be described in terms of a forward-Rayleigh scattering mechanism, with trapping forces being dependent on the positioning within the commonly non-uniform intensity beam profile. In such a scheme, nanoparticles are commonly attracted to local potential energy minima, ordinarily towards the centre of the beam. For achiral particles the pertinent material response property usually entails an electronic polarizability involving transition electric dipole moments. However, in the case of chiral molecules, additional effects arise through the engagement of magnetic counterpart transition dipoles. It emerges that, when circularly polarized light is used for the trapping, a discriminatory response can be identified between left- and right-handed polarizations. Developing a quantum framework to accurately describe this phenomenon, with a tensor formulation to correctly represent the relevant molecular properties, the theory leads to exact analytical expressions for the associated energy landscape contributions. Specific results are identified for liquids and solutions, both for isotropic media and also where partial alignment arises due to a static electric field. The paper concludes with a pragmatic analysis of the scope for achieving enantiomer separation by such methods.

  14. Chirally symmetric strong and electroweak interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rajpoot, S.

    1988-07-21

    Strong and electroweak interactions may be a relic of the spontaneous breakdown of a chirally symmetric colour-flavour gauge group. The minimum possibility of such a structure that is symmetric between left and right is SU(3)/sub L/xSU(3)/sub R/xSU(2)/sub L/xSU(2)/sub R/xU(1)/sub B-L/ where quantum chromodynamics originates in the chiral colour group SU(3)/sub L/xSU(3)/sub R/ and the electroweak interaction originates in the ambidextrous electroweak interaction group SU(2)/sub L/xSU(2)/sub R/xU(1)/sub B-L/. The chiral anomalies are cancelled by adding a set of fermions that transform as singlets under the weak interaction group SU(2)/sub L/xSU(2)/sub R/. This model requires only three Higgs representations to break the proposed gauge symmetry to SU(3)/sup C/xU(1)/sub em/ and give masses to all the quarks and leptons of the theory. All fermion masses are 'see-saw' masses.

  15. Chiral bosonization for non-commutative fields

    Energy Technology Data Exchange (ETDEWEB)

    Das, Ashok [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States)]. E-mail: das@pas.rochester.edu; Gamboa, Jorge [Departamento de Fisica, Universidad de Santiago de Chile, Casilla 307, Santiago 2 (Chile); Mendez, Fernando [INFN, Laboratorio Nazionali del Gran Sasso, SS, 17bis, 67010 Asergi, L' Aquila (Italy); Lopez-Sarrion, Justo [Departamento de Fisica Teorica, Universidad de Zaragoza, Zaragoza 50009 (Spain)

    2004-05-01

    A model of chiral bosons on a non-commutative field space is constructed and new generalized bosonization (fermionization) rules for these fields are given. The conformal structure of the theory is characterized by a level of the Kac-Moody algebra equal to (1+{theta}{sup 2}) where {theta} is the non-commutativity parameter and chiral bosons living in a non-commutative fields space are described by a rational conformal field theory with the central charge of the Virasoro algebra equal to 1. The non-commutative chiral bosons are shown to correspond to a free fermion moving with a speed equal to c' = c(1+{theta}{sup 2}){sup 1/2} where c is the speed of light. Lorentz invariance remains intact if c is rescaled by c{yields}c'. The dispersion relation for bosons and fermions, in this case, is given by {omega} = c' vertical bar k vertical bar. (author)

  16. Enantiomeric separations of chiral pharmaceuticals using chirally modified tetrahexahedral Au nanoparticles

    Science.gov (United States)

    Shukla, N.; Yang, D.; Gellman, A. J.

    2016-06-01

    Tetrahexahedral (THH, 24-sided) Au nanoparticles modified with D- or L-cysteine (Cys) have been used as enantioselective separators of the chiral pharmaceutical propranolol (PLL) in solution phase. Polarimetry has been used to measure the rotation of linearly polarized light by solutions containing mixtures of PLL and Cys/THH-Au NPs with varying enantiomeric excesses of each. Polarimetry yields clear evidence of enantiospecific adsorption of PLL onto the Cys/THH-Au NPs. This extends prior work using propylene oxide as a test chiral probe, by using the crystalline THH Au NPs with well-defined facets to separate a real pharmaceutical. This work suggests that chiral nanoparticles, coupled with a density separation method such as centrifugation, could be used for enantiomeric purification of real pharmaceuticals. A simple robust model developed earlier has also been used to extract the enantiospecific equilibrium constants for R- and S-PLL adsorption onto the D- and L-Cys/THH-Au NPs.

  17. Reflection and transmission coefficients of multiple chiral layers

    Institute of Scientific and Technical Information of China (English)

    SABAH Cumali; UCKUN Savas

    2006-01-01

    This paper presents a general analysis of reflection and transmission coefficients of multiple chiral layers in detail. Reflection and transmission coefficients through multiple chiral layers are computed and presented particularly for the incident wave of parallel polarization for a number of cases-a wide range of incidence angle, neigh- boring center frequency and different chirality parameters. Transfer matrix method is used in the analysis. From the numerical results, it can be seen that multiple chiral layers may be used as a polarization-conversion transmission filter and antireflection filter at the frequency band around the central frequency.

  18. Chiral nucleon-nucleon forces in nuclear structure calculations

    Directory of Open Access Journals (Sweden)

    Coraggio L.

    2016-01-01

    Full Text Available Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.

  19. Experimental Demonstration of Spontaneous Chirality in a Nonlinear Microresonator

    Science.gov (United States)

    Cao, Qi-Tao; Wang, Heming; Dong, Chun-Hua; Jing, Hui; Liu, Rui-Shan; Chen, Xi; Ge, Li; Gong, Qihuang; Xiao, Yun-Feng

    2017-01-01

    Chirality is an asymmetric property widely found in nature. Here, we propose and demonstrate experimentally the spontaneous emergence of chirality in an on-chip ultrahigh-Q whispering-gallery microresonator, without broken parity or time-reversal symmetry. This counterintuitive effect arises due to the inherent Kerr-nonlinearity-modulated coupling between clockwise and counterclockwise propagating waves. Above an input threshold of a few hundred microwatts, the initial chiral symmetry is broken spontaneously, and the counterpropagating output ratio exceeds 20 ∶1 with bidirectional inputs. The spontaneous chirality in an on-chip microresonator holds great potential in studies of fundamental physics and applied photonic devices.

  20. Comparison of chiral metamaterial designs for repulsive Casimir force

    Science.gov (United States)

    Zhao, R.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.

    2010-06-01

    In our previous work [R. Zhao, J. Zhou, Th. Koschny, E. N. Economou, and C. M. Soukoulis, Phys. Rev. Lett. 103, 103602 (2009)], we found that repulsive Casimir forces could be realized by using chiral metamaterials if the chirality is strong enough. In this work, we check four different chiral metamaterial designs (i.e., Twisted-Rosettes, Twisted-Crosswires, Four-U-SRRs, and Conjugate-Swastikas) and find that the designs of Four-U-SRRs and Conjugate-Swastikas are the most promising candidates to realize repulsive Casimir force because of their large chirality and the small ratio of structure length scale to resonance wavelength.

  1. Comparison of Chiral Metamaterial Designs for Repulsive Casimir Force

    OpenAIRE

    Zhao, R.; Koschny, Th.; Economou, E. N.; C M Soukoulis

    2009-01-01

    In our previous work [Phys. Rev. Lett. 103, 103602 (2009)], we found that repulsive Casimir forces could be realized by using chiral metamaterials if the chirality is strong enough. In this work, we check four different chiral metamaterial designs (i.e., Twisted-Rosettes, Twisted-Crosswires, Four-U-SRRs, and Conjugate-Swastikas) and find that the designs of Four-U-SRRs and Conjugate-Swastikas are the most promising candidates to realize repulsive Casimir force because of their large chirality...

  2. Chiral nucleon-nucleon forces in nuclear structure calculations

    CERN Document Server

    Coraggio, L; Holt, J W; Itaco, N; Machleidt, R; Marcucci, L E; Sammarruca, F

    2016-01-01

    Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.

  3. Enantiomer-Specific State Transfer of Chiral Molecules

    CERN Document Server

    Eibenberger, Sandra; Patterson, David

    2016-01-01

    State-selective enantiomeric excess is realized using microwave-driven coherent population transfer. The method selectively promotes either R- or S- molecules to a higher rotational state by phase-controlled microwave pulses that drive electric-dipole allowed rotational transitions. We demonstrate the method using a racemic mixture of 1,2-propanediol. This method of chiral enrichment can be applied to nearly any chiral molecule that can be vaporized and cooled to the point where rotationally resolved spectroscopy is possible, including molecules that rapidly racemize. The rapid chiral switching demonstrated here allows for new applications in high-precision spectroscopic searches for parity violation in chiral molecules.

  4. From enemies to friends chiral symmetry on the lattice

    CERN Document Server

    Hernández, Pilar; Lellouch, L P; Hernandez, Pilar; Jansen, Karl; Lellouch, Laurent

    2002-01-01

    The physics of strong interactions is invariant under the exchange of left-handed and right-handed quarks, at least in the massless limit. This invariance is reflected in the chiral symmetry of quantum chromodynamics. Surprisingly, it has become clear only recently how to implement this important symmetry in lattice formulations of quantum field theories. We will discuss realizations of exact lattice chiral symmetry and give an example of the computation of a physical observable in quantum chromodynamics where chiral symmetry is important. This calculation is performed by relying on finite size scaling methods as predicted by chiral perturbation theory.

  5. Charge fluctuations in chiral models and the QCD phase transition

    CERN Document Server

    Skokov, V; Karsch, F; Redlich, K

    2011-01-01

    We consider the Polyakov loop-extended two flavor chiral quark--meson model and discuss critical phenomena related with the spontaneous breaking of the chiral symmetry. The model is explored beyond the mean-field approximation in the framework of the functional renormalisation group. We discuss properties of the net-quark number density fluctuations as well as their higher cumulants. We show that with the increasing net-quark number density, the higher order cumulants exhibit a strong sensitivity to the chiral crossover transition. We discuss their role as probes of the chiral phase transition in heavy-ion collisions at RHIC and LHC.

  6. Heavy-Light Mesons in Chiral AdS/QCD

    CERN Document Server

    Liu, Yizhuang

    2016-01-01

    We discuss a minimal holographic model for the description of heavy-light and light mesons with chiral symmetry, defined in a slab of AdS space. The model consists of a pair of chiral Yang-Mills and tachyon fields with specific boundary conditions that break spontaneously chiral symmetry in the infrared. The heavy-light spectrum and decay constants are evaluated explicitly. In the heavy mass limit the model exhibits both heavy-quark and chiral symmetry and allows for the explicit derivation of the one-pion axial couplings to the heavy-light mesons.

  7. Solvent-driven chiral-interaction reversion for organogel formation.

    Science.gov (United States)

    Qing, Guangyan; Shan, Xingxing; Chen, Wenrui; Lv, Ziyu; Xiong, Peng; Sun, Taolei

    2014-02-17

    For chiral gels and related applications, one of the critical issues is how to modulate the stereoselective interaction between the gel and the chiral guest precisely, as well as how to translate this information into the macroscopic properties of materials. Herein, we report that this process can also be modulated by nonchiral solvents, which can induce a chiral-interaction reversion for organogel formation. This process could be observed through the clear difference in gelation speed and the morphology of the resulting self-assembly. This chiral effect was successfully applied in the selective separation of quinine enantiomers and imparts "smart" merits to the gel materials.

  8. Magnetic fields and chiral asymmetry in the early hot universe

    Science.gov (United States)

    Sydorenko, Maksym; Tomalak, Oleksandr; Shtanov, Yuri

    2016-10-01

    In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of `inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentially washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.

  9. Experimental Overview of the Search for Chiral Effects at RHIC

    Science.gov (United States)

    Wang, Gang

    2017-01-01

    In high-energy heavy-ion collisions, various novel transport phenomena in local chiral domains result from the interplay of quantum anomalies with magnetic field and vorticity, and could survive the expansion of the fireball and be detected in experiments. Among these phenomena are the chiral magnetic effect, the chiral vortical effect and the chiral magnetic wave, the experimental searches for which have aroused extensive interest. This review will describe the current status of experimental studies at Relativistic Heavy Ion Collider at BNL, and outline the future work in experiment needed to eliminate the existing uncertainties in the interpretation of the data.

  10. Experimental results on chiral magnetic and vortical effects

    CERN Document Server

    Wang, Gang

    2016-01-01

    Various novel transport phenomena in chiral systems result from the interplay of quantum anomalies with magnetic field and vorticity in high-energy heavy-ion collisions, and could survive the expansion of the fireball and be detected in experiments. Among them are the chiral magnetic effect, the chiral vortical effect and the chiral magnetic wave, the experimental searches for which have aroused extensive interest. The goal of this review is to describe the current status of experimental studies at Relativistic Heavy Ion Collider at BNL and the Large Hadron Collider at CERN, and to outline the future work in experiment needed to eliminate the existing uncertainties in the interpretation of the data.

  11. Single beam optical conveyor belt for chiral particles

    CERN Document Server

    Fernandes, David E

    2016-01-01

    We propose a novel paradigm to selectively manipulate and transport small engineered chiral particles and discriminate different enantiomers using unstructured chiral light. It is theoretically shown that the response of a chiral metamaterial particle may be tailored to enable an optical conveyor belt operation with no optical traps, such that for a fixed incident light helicity and independent of the nanoparticle location, it is either steadily pushed towards the direction of the photon flow or steadily pulled against the photon flow. Our findings create new opportunities for unconventional optical manipulations of tailored nanoparticles and may have applications in sorting racemic mixtures of artificial chiral molecules and in particle delivery.

  12. Is the Chiral Vortical Effect Vanishing in Heavy Ion Collisions?

    CERN Document Server

    Landsteiner, Karl; Pena-Benitez, Francisco

    2013-01-01

    We study the frequency dependence of all the chiral vortical and magnetic conductivities for a relativistic chiral gas of free fermions and for a strongly coupled CFT with holographic dual in four dimensions. Both systems present gauge and gravitational anomalies and we compute their contribution to the conductivities. The chiral vortical conductivities and the chiral magnetic conductivity in the energy current show an unexpected frequency dependence in the form of a delta centered at zero frequency. We argue that this makes the CVE practically unobservable in heavy ion collisions. In the appendix we discuss why the CME seems to vanish in the consistent current for a particular implementation of the axial chemical potential.

  13. The effect of the chiral chemical potential on the chiral phase transition in the NJL model with different regularization schemes

    CERN Document Server

    Yu, Lang; Huang, Mei

    2015-01-01

    We study the chiral phase transition in the presence of the chiral chemical potential $\\mu_5$ using the two-flavor Nambu--Jona-Lasinio model. In particular, we analyze the reason why one can obtain two opposite behaviors of the chiral critical temperature as a function of $\\mu_5$ in the framework of different regularization schemes. We compare the modifications of the chiral condensate and the critical temperature due to $\\mu_5$ in different regularization schemes, analytically and numerically. Finally, we find that, for the conventional hard-cutoff regularization scheme, the increasing dependence of the critical temperature on the chiral chemical potential is an artifact, which is caused by the fact that it does not include complete contribution from the thermal fluctuations. When the thermal contribution is fully taken into account, the chiral critical temperature should decrease with $\\mu_5$.

  14. Chiral behavior of light meson form factors in 2+1 flavor QCD with exact chiral symmetry

    CERN Document Server

    Kaneko, T; Cossu, G; Feng, X; Fukaya, H; Hashimoto, S; Noaki, J; Onogi, T

    2016-01-01

    We present a study of chiral behavior of light meson form factors in QCD with three flavors of overlap quarks. Gauge ensembles are generated at single lattice spacing 0.12 fm with pion masses down to 300 MeV. The pion and kaon electromagnetic form factors and the kaon semileptonic form factors are precisely calculated using the all-to-all quark propagator. We discuss their chiral behavior using the next-to-next-to-leading order chiral perturbation theory.

  15. Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

    Directory of Open Access Journals (Sweden)

    Simon A. Herbert

    2014-11-01

    Full Text Available The diastereoselective oxazoline-directed lithiation of calix[4]arenes is reported with diastereoselective ratios of greater than 100:1 in some instances. Notably, it has been found that the opposite diastereomer can be accessed via this approach merely through the choice of an alkyllithium reagent. The inherently chiral oxazoline calix[4]arenes have also been preliminarily examined as ligands in the palladium-catalyzed Tsuji–Trost allylation reaction, returning results comparable to their planar chiral ferrocene counterparts pointing towards future application of these types of compounds.

  16. Evaluation of sulfated maltodextrin as a novel anionic chiral selector for the enantioseparation of basic chiral drugs by capillary electrophoresis.

    Science.gov (United States)

    Tabani, Hadi; Mahyari, Mojtaba; Sahragard, Ali; Fakhari, Ali Reza; Shaabani, Ahmad

    2015-01-01

    Introducing a new class of chiral selectors is an interesting work and this issue is still one of the hot topics in separation science and chirality. In this study, for the first time, sulfated maltodextrin (MD) was synthesized as a new anionic chiral selector and then it was successfully applied for the enantioseparation of five basic drugs (amlodipine, hydroxyzine, fluoxetine, tolterodine, and tramadol) as model chiral compounds using CE. This chiral selector has two recognition sites: a helical structure and a sulfated group which contribute to three corresponding driving forces; inclusion complexation, electrostatic interaction, and hydrogen binding. Under the optimized condition (buffer solution: 50 mM phosphate (pH 3.0) and 2% w/v sulfated MD; applied voltage: 18 kV; temperature: 20°C), baseline enantioseparation was observed for all mentioned chiral drugs. When instead of sulfated MD neutral MD was used under the same condition, no enantioseparation was observed which means the resolution power of sulfated MD is higher than neutral MD due to the electrostatic interaction between sulfated groups and protonated chiral drugs. Also, the countercurrent mobility of negatively charged MD (sulfated MD) allows more interactions between the chiral selector and chiral drugs and this in turn results in a successful resolution for the enantiomers. Furthermore, a higher concentration of neutral MD (approximately five times) is necessary to achieve the equivalent resolution compared with the negatively charged MD.

  17. Molecular-level Design of Heterogeneous Chiral Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gellman, Andrew John [Carnegie Mellon University; Sholl, David S. [Georgia Institute of Technology; Tysoe, Wilfred T. [University of Wisconsin - Milwaukee; Zaera, Francisco [University of California at Riverside

    2013-04-28

    Understanding and controlling selectivity is one of the key challenges in heterogeneous catalysis. Among problems in catalytic selectivity enantioselectivity is perhaps the most the most challenging. The primary goal of the project on “Molecular-level Design of Heterogeneous Chiral Catalysts” is to understand the origins of enantioselectivity on chiral heterogeneous surfaces and catalysts. The efforts of the project team include preparation of chiral surfaces, characterization of chiral surfaces, experimental detection of enantioselectivity on such surfaces and computational modeling of the interactions of chiral probe molecules with chiral surfaces. Over the course of the project period the team of PI’s has made some of the most detailed and insightful studies of enantioselective chemistry on chiral surfaces. This includes the measurement of fundamental interactions and reaction mechanisms of chiral molecules on chiral surfaces and leads all the way to rationale design and synthesis of chiral surfaces and materials for enantioselective surface chemistry. The PI’s have designed and prepared new materials for enantioselective adsorption and catalysis. Naturally Chiral Surfaces • Completion of a systematic study of the enantiospecific desorption kinetics of R-3-methylcyclohexanone (R-3-MCHO) on 9 achiral and 7 enantiomeric pairs of chiral Cu surfaces with orientations that span the stereographic triangle. • Discovery of super-enantioselective tartaric acid (TA) and aspartic acid (Asp) decomposition as a result of a surface explosion mechanism on Cu(643)R&S. Systematic study of super-enantiospecific TA and Asp decomposition on five enantiomeric pairs of chiral Cu surfaces. • Initial observation of the enantiospecific desorption of R- and S-propylene oxide (PO) from Cu(100) imprinted with {3,1,17} facets by L-lysine adsorption. Templated Chiral Surfaces • Initial observation of the enantiospecific desorption of R- and S-PO from Pt(111) and Pd(111

  18. Chiral charge erasure via thermal fluctuations of magnetic helicity

    Energy Technology Data Exchange (ETDEWEB)

    Long, Andrew J. [Kavli Institute for Cosmological Physics, University of Chicago,Chicago, Illinois 60637 (United States); Sabancilar, Eray [Institut de Théorie des Phénoménes Physiques, Ecole Polytechnique Fédérale de Lausanne,CH-1015 Lausanne (Switzerland)

    2016-05-11

    We consider a relativistic plasma of fermions coupled to an Abelian gauge field and carrying a chiral charge asymmetry, which might arise in the early Universe through baryogenesis. It is known that on large length scales, λ≳1/(αμ{sub 5}), the chiral anomaly opens an instability toward the erasure of chiral charge and growth of magnetic helicity. Here the chemical potential μ{sub 5} parametrizes the chiral asymmetry and α is the fine-structure constant. We study the process of chiral charge erasure through the thermal fluctuations of magnetic helicity and contrast with the well-studied phenomenon of Chern-Simons number diffusion. Through the fluctuation-dissipation theorem we estimate the amplitude and time scale of helicity fluctuations on the length scale λ, finding δ H∼λT and τ∼αλ{sup 3}T{sup 2} for a relativistic plasma at temperature T. We argue that the presence of a chiral asymmetry allows the helicity to grow diffusively for a time t∼T{sup 3}/(α{sup 5}μ{sub 5}{sup 4}) until it reaches an equilibrium value H∼μ{sub 5}T{sup 2}/α, and the chiral asymmetry is partially erased. If the chiral asymmetry is small, μ{sub 5}chiral charge erasure is found to be slower than the chiral magnetic effect for which t∼T/(α{sup 3}μ{sub 5}{sup 2}). This mechanism for chiral charge erasure can be important for the hypercharge sector of the Standard Model as well as extensions including U(1) gauge interactions, such as asymmetric dark matter models.

  19. The significance of chirality in drug design and development.

    Science.gov (United States)

    Brooks, W H; Guida, W C; Daniel, K G

    2011-01-01

    Proteins are often enantioselective towards their binding partners. When designing small molecules to interact with these targets, one should consider stereoselectivity. As considerations for exploring structure space evolve, chirality is increasingly important. Binding affinity for a chiral drug can differ for diastereomers and between enantiomers. For the virtual screening and computational design stage of drug development, this problem can be compounded by incomplete stereochemical information in structure libraries leading to a "coin toss" as to whether or not the "ideal" chiral structure is present. Creating every stereoisomer for each chiral compound in a structure library leads to an exponential increase in the number of structures resulting in potentially unmanageable file sizes and screening times. Therefore, only key chiral structures, enantiomeric pairs based on relative stereochemistry need be included, and lead to a compromise between exploration of chemical space and maintaining manageable libraries. In clinical environments, enantiomers of chiral drugs can have reduced, no, or even deleterious effects. This underscores the need to avoid mixtures of compounds and focus on chiral synthesis. Governmental regulations emphasizing the need to monitor chirality in drug development have increased. The United States Food and Drug Administration issued guidelines and policies in 1992 concerning the development of chiral compounds. These guidelines require that absolute stereochemistry be known for compounds with chiral centers and that this information should be established early in drug development in order that the analysis can be considered valid. From exploration of structure space to governmental regulations it is clear that the question of chirality in drug design is of vital importance.

  20. Chiral charge erasure via thermal fluctuations of magnetic helicity

    Science.gov (United States)

    Long, Andrew J.; Sabancilar, Eray

    2016-05-01

    We consider a relativistic plasma of fermions coupled to an Abelian gauge field and carrying a chiral charge asymmetry, which might arise in the early Universe through baryogenesis. It is known that on large length scales, λ gtrsim 1/(αμ5), the chiral anomaly opens an instability toward the erasure of chiral charge and growth of magnetic helicity. Here the chemical potential μ5 parametrizes the chiral asymmetry and α is the fine-structure constant. We study the process of chiral charge erasure through the thermal fluctuations of magnetic helicity and contrast with the well-studied phenomenon of Chern-Simons number diffusion. Through the fluctuation-dissipation theorem we estimate the amplitude and time scale of helicity fluctuations on the length scale λ, finding δScript H ~ λT and τ ~ αλ3T2 for a relativistic plasma at temperature T. We argue that the presence of a chiral asymmetry allows the helicity to grow diffusively for a time t ~ T3/(α5μ54) until it reaches an equilibrium value Script H ~ μ5T2/α, and the chiral asymmetry is partially erased. If the chiral asymmetry is small, μ5 < T/α, this avenue for chiral charge erasure is found to be slower than the chiral magnetic effect for which t ~ T/(α3μ52). This mechanism for chiral charge erasure can be important for the hypercharge sector of the Standard Model as well as extensions including U(1) gauge interactions, such as asymmetric dark matter models.