A new generation of chiral phase-transfer catalysts.
Kaneko, Shiho; Kumatabara, Yusuke; Shirakawa, Seiji
2016-06-28
Phase-transfer catalysis has long been recognized as a versatile method for organic synthesis. In particular, over more than the past three decades, asymmetric phase-transfer catalysis based on the use of structurally well-defined chiral catalysts has become a topic of great scientific interest. Although various effective chiral catalysts have already been reported and these catalysts were utilized for practical asymmetric transformations, further design and development of new chiral phase-transfer catalysts are still attractive research subjects in organic chemistry due to the high utility and practicability of phase-transfer-catalyzed reactions. This review focuses on the recent examples of newly designed effective chiral phase-transfer catalysts. PMID:26754659
Enantiomer-Specific State Transfer of Chiral Molecules
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.
Chirality transfer from gold nanocluster to adsorbate evidenced by vibrational circular dichroism
Dolamic, Igor; Varnholt, Birte; Bürgi, Thomas
2015-05-01
The transfer of chirality from one set of molecules to another is fundamental for applications in chiral technology and has likely played a crucial role for establishing homochirality on earth. Here we show that an intrinsically chiral gold cluster can transfer its handedness to an achiral molecule adsorbed on its surface. Solutions of chiral Au38(2-PET)24 (2-PET=2-phenylethylthiolate) cluster enantiomers show strong vibrational circular dichroism (VCD) signals in vibrations of the achiral adsorbate. Density functional theory (DFT) calculations reveal that 2-PET molecules adopt a chiral conformation. Chirality transfer from the cluster to the achiral adsorbate is responsible for the preference of one of the two mirror images. Intermolecular interactions between the adsorbed molecules on the crowded cluster surface seem to play a dominant role for the phenomena. Such chirality transfer from metals to adsorbates likely plays an important role in heterogeneous enantioselective catalysis.
Contini, G.; Turchini, S.; Sanna, Simone;
2012-01-01
state, that the presence of molecular chiral domains induces asymmetry in the interaction with the substrate and locally transfers the chiral character to the underlying metal atoms participating in the adsorption process; combined information related to the asymmetry of the initial electronic state......Studies of self-assembled chiral molecules on achiral metallic surfaces have mostly focused on the determination of the geometry of adsorbates and their electronic structure. The aim of this paper is to provide direct information on the chirality character of the system and on the chirality......, which is expected to be chiral, and the final electronic state, which locally probes the asymmetry of the potential, has been obtained. Identification of chirality in the adsorption footprint sheds new light on the transfer of chirality from a chiral modifier to a symmetric metal surface and represents...
Atropselective Syntheses of (−) and (+) Rugulotrosin A Utilizing Point-to-Axial Chirality Transfer
Qin, Tian; Skraba-Joiner, Sarah L.; Khalil, Zeinab G.; Johnson, Richard P.; Capon, Robert J.; Porco, John A.
2015-01-01
Chiral, dimeric natural products containing complex structures and interesting biological properties have inspired chemists and biologists for decades. A seven step total synthesis of the axially chiral, dimeric tetrahydroxanthone natural product rugulotrosin A is described. The synthesis employs a one-pot Suzuki coupling/dimerization to generate the requisite 2,2'-linked biaryl linkage. Highly selective point-to-axial chirality transfer was achieved using palladium catalysis with achiral pho...
LIU Ketang
2013-02-01
Full Text Available Functional graphite oxide materials were synthesized through the Hummers chemical oxidation of graphite.Heterogeneous catalyst was prepared via direct grafting diamine-based chiral ligand to graphite oxide followed by the complexation with organorhodium complex.Such a chiral rhodium catalyst exhibited high catalytic activity and enantioselectivity in asymmetric transfer hydrogenation of aromatic ketones in aqueous medium under mild condition.
Acoustic orbital angular momentum transfer to matter by chiral scattering
Wunenburger, Régis; Israel, Juan; Lozano, Vazquez; Brasselet, Etienne
2015-01-01
We report on orbital angular momentum exchange between sound and matter mediated by a non-dissipative chiral scattering process. An experimental demonstration is made possible by irradiating a three-dimensional printed, spiral-shaped chiral object with an incident ultrasonic beam carrying zero orbital angular momentum. Chiral refraction is shown to impart a nonzero orbital angular momentum to the scattered field and to rotate the object. This result constitutes a proof of concept of a novel k...
Acoustic orbital angular momentum transfer to matter by chiral scattering
Wunenburger, Régis; Israel Vazquez Lozano, Juan; Brasselet, Etienne
2015-10-01
We report on orbital angular momentum exchange between sound and matter mediated by a non-dissipative chiral scattering process. An experimental demonstration is made possible by irradiating a three-dimensional printed, spiral-shaped chiral object with an incident ultrasonic beam carrying zero orbital angular momentum. Chiral refraction is shown to impart a nonzero orbital angular momentum to the scattered field and to rotate the object. This result constitutes a proof of concept of a novel kind of acoustic angular manipulation of matter.
Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry
Michiya Fujiki
2014-08-01
Full Text Available Controlled mirror symmetry breaking arising from chemical and physical origin is currently one of the hottest issues in the field of supramolecular chirality. The dynamic twisting abilities of solvent molecules are often ignored and unknown, although the targeted molecules and polymers in a fluid solution are surrounded by solvent molecules. We should pay more attention to the facts that mostly all of the chemical and physical properties of these molecules and polymers in the ground and photoexcited states are significantly influenced by the surrounding solvent molecules with much conformational freedom through non-covalent supramolecular interactions between these substances and solvent molecules. This review highlights a series of studies that include: (i historical background, covering chiral NaClO3 crystallization in the presence of d-sugars in the late 19th century; (ii early solvent chirality effects for optically inactive chromophores/fluorophores in the 1960s–1980s; and (iii the recent development of mirror symmetry breaking from the corresponding achiral or optically inactive molecules and polymers with the help of molecular chirality as the solvent use quantity.
Sara J. Krivickas
2015-09-01
Full Text Available Chiral molecular crystals built up by chiral molecules without inversion centers have attracted much interest owing to their versatile functionalities related to optical, magnetic, and electrical properties. However, there is a difficulty in chiral crystal growth due to the lack of symmetry. Therefore, we made the molecular design to introduce intermolecular hydrogen bonds in chiral crystals. Racemic and enantiopure bis(ethylenedithiotetrathiafulvalene (BEDT-TTF derivatives possessing hydroxymethyl groups as the source of hydrogen bonds were designed. The novel racemic trans-vic-(hydroxymethyl(methyl-BEDT-TTF 1, and racemic and enantiopure trans-vic-bis(hydroxymethyl-BEDT-TTF 2 were synthesized. Moreover, the preparations, crystal structure analyses, and electrical resistivity measurements of the novel achiral charge transfer salt θ21-[(S,S-2]3[(R,R-2]3(ClO42 and the chiral salt α’-[(R,R-2]ClO4(H2O were carried out. In the former θ21-[(S,S-2]3[(R,R-2]3(ClO42, there are two sets of three crystallographically independent donor molecules [(S,S-2]2[(R,R-2] in a unit cell, where the two sets are related by an inversion center. The latter α’-[(R,R-2]ClO4(H2O is the chiral salt with included solvent H2O, which is not isostructural with the reported chiral salt α’-[(S,S-2]ClO4 without H2O, but has a similar donor arrangement. According to the molecular design by introduction of hydroxy groups and a ClO4− anion, many intermediate-strength intermolecular hydrogen bonds (2.6–3.0 Å were observed in these crystals between electron donor molecules, anions, and included H2O solvent, which improve the crystallinity and facilitate the extraction of physical properties. Both salts are semiconductors with relatively low resistivities at room temperature and activation energies of 1.2 ohm cm with Ea = 86 meV for θ21-[(S,S-2]3[(R,R-2]3(ClO42 and 0.6 ohm cm with Ea = 140 meV for α'-[(R,R-2]2ClO4(H2O, respectively. The variety of donor arrangements
Surface enhanced resonance ROA (SERROA) as a novel probe of chirality transfer
Pour, S. O.; Rocks, L.; Faulds, K.; Graham, D.; Parchaňský, Václav; Bouř, Petr; Blanch, E. W.
Vienna: Vienna University of Technology , 2015 - (Lendl, B.; Koch, C.; Kraft, M.; Ofner, J.; Ramer, G.). s. 260-261 ISBN 978-3-200-04205-6. [ICAVS8. International Conference on Advanced Vibrational Spectroscopy /8./. 12.07.2015-17.07.2015, Vienna] Institutional support: RVO:61388963 Keywords : ROA * SERS * chirality transfer * resonance * nanosensors Subject RIV: CF - Physical ; Theoretical Chemistry
Atropselective Syntheses of (−) and (+) Rugulotrosin A Utilizing Point-to-Axial Chirality Transfer
Qin, Tian; Skraba-Joiner, Sarah L.; Khalil, Zeinab G.; Johnson, Richard P.; Capon, Robert J.; Porco, John A.
2014-01-01
Chiral, dimeric natural products containing complex structures and interesting biological properties have inspired chemists and biologists for decades. A seven step total synthesis of the axially chiral, dimeric tetrahydroxanthone natural product rugulotrosin A is described. The synthesis employs a one-pot Suzuki coupling/dimerization to generate the requisite 2,2'-linked biaryl linkage. Highly selective point-to-axial chirality transfer was achieved using palladium catalysis with achiral phosphine ligands. Single X-ray crystal diffraction data was obtained to confirm both the atropisomeric configuration and absolute stereochemistry of rugulotrosin A. Computational studies are described to rationalize the atropselectivity observed in the key dimerization step. Comparison of the crude fungal extract with synthetic rugulotros in A and its atropisomer verified that nature generates a single atropisomer of the natural product. PMID:25698333
Three-dimensional chirality transfer in rubrene multilayer islands on Au(111).
Pivetta, Marina; Blüm, Marie-Christine; Patthey, François; Schneider, Wolf-Dieter
2009-04-01
The growth of rubrene (C(42)H(28), 5,6,11,12-tetraphenylnaphthacene) multilayer islands up to a thickness of six layers on a Au(111) surface has been investigated by scanning tunneling microscopy. The molecules self-organize in parallel twin rows, forming mirror domains of defined local structural chirality. Each layer is composed of twin-row domains of the same structural handedness rotated by 120 degrees with respect to each other. Moreover, this structural chirality is transferred to all successive layers in the island, resulting in the formation of three-dimensional objects having a defined structural chirality. The centered rectangular surface unit cell differs from the one characteristic for the single-crystal orthorhombic phase. PMID:19338362
Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer
Coles, R. J.; Price, D. M.; Dixon, J. E.; Royall, B.; Clarke, E.; Kok, P.; Skolnick, M. S.; Fox, A. M.; Makhonin, M. N.
2016-03-01
Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95+/-5% and have potential to serve as the basis of spin-logic and network implementations.
Shen Luan Yu; Yan Yun Li; Zhen Rong Dong; Jing Xing Gao
2012-01-01
Novel chiral tetraaza ligands (R)-N,N'-bis[2-(piperidin-l-yl)benzylidene]propane-1,2-diamine 6 and (S)-N-[2-(piperidin-1-yl)benzylidene]-3-{ [2-(piperidin-1-yl)benzylidene]amino}-alanine sodium salt 7 have been synthesized and fully characterized by NMR,IR,MS and CD spectra.The catalytic property of the ligands was investigated in Ir-catalyzed enantioselective transfer hydrogenation of ketones.The corresponding optical active alcohols were obtained with high yields and moderate ees under mild reaction conditions.
Direct Observation of Molecular Preorganization for Chirality Transfer on a Catalyst Surface
Demers-Carpentier, Vincent; Goubert,, Guillaume; Masini, Federico; Lafleur-Lambert, Raphael; Dong, Yi; Lavoie, Stéphane; Mahieu, Gautier; Boukouvalas, John; Gao, Haili; Rasmussen, Anton Michael Havelund; Ferrighi, Lara; Pan, Yunxiang; Hammer, Bjørk; McBreen, Peter H.
2011-01-01
functional theory calculations reveals the stereodirecting forces governing preorganization into precise chiral modifier-substrate bimolecular surface complexes. The study shows that the chiral modifier induces prochiral switching on the surface and that different prochiral ratios prevail at different...... submolecular binding sites on the modifier at the reaction temperature....
Color transparency is the vanishing of initial and final state interactions, predicted by QCD to occur in high momentum transfer quasielastic nuclear reactions. For specific reactions involving nucleons, the initial and final state interactions are expected to be dominated by exchanges of pions. We argue that these interactions are also suppressed in high momentum transfer nuclear quasielastic reactions; this is open-quotes chiral transparency.close quotes We show that studies of the e3He→e'Δ++nn reaction could reveal the influence of chiral transparency. copyright 1997 The American Physical Society
Dixit, Manish Kumar; Pandey, Vinay Kumar; Dubey, Mrigendra
2016-04-13
Three l-tartaric acid based symmetrical A-π-D-chiral-D-π-A type structural isomeric nitrobenzylidenes () have been synthesized with intent to achieve isomer specific metallogels with intramolecular charge transfer properties. Alkali metal ions in these systems not only trigger charge transfer but also play a vital role in gelation. The presence of intramolecular rather than intermolecular charge transfer as well as aggregation has been well established by various kinds of experiments using UV-vis, CD, (1)H NMR, DFT and crystallography techniques. The role of alkali metal ions in triggering ICT was proved by titration with their respective crown ethers. Notably, Na(+) afforded twisted fiber morphology whilst Li(+) gave merely long range fibers. The true gel phase material was proved by detailed rheological studies. PMID:26974120
Touge, Taichiro; Nara, Hideki; Fujiwhara, Mitsuhiko; Kayaki, Yoshihito; Ikariya, Takao
2016-08-17
A concise asymmetric transfer hydrogenation of diaryl ketones, promoted by bifunctional Ru complexes with an etherial linkage between 1,2-diphenylethylenediamine (DPEN) and η(6)-arene ligands, was successfully developed. Because of the effective discrimination of substituents at the ortho position on the aryl group, unsymmetrical benzophenones were smoothly reduced in a 5:2 mixture of formic acid and triethylamine with an unprecedented level of excellent enantioselectivity. For the non-ortho-substituted benzophenones, the oxo-tethered catalyst electronically discerned biased substrates, resulting in attractive performance yielding chiral diarylmethanols with >99% ee. PMID:27463264
ARUN KUMAR PANDIA KUMAR; ASHOKA G SAMUELSON
2016-09-01
Chiral ruthenium half-sandwich complexes were prepared using a chelating diamine made from proline with a phenyl, ethyl, or benzyl group, instead of hydrogen on one of the coordinating arms. Three of these complexes were obtained as single diastereoisomers and their configuration identified by X-ray crystallography. The complexes are recyclable catalysts for the reduction of ketones to chiral alcohols in water. A ruthenium hydride species is identified as the active species by NMR spectroscopy and isotopic labelling experiments.Maximum enantio-selectivity was attained when a phenyl group was directly attached to the primary amine on the diamine ligand derived from proline.
Transport evidence for Fermi-arc-mediated chirality transfer in the Dirac semimetal Cd3As2
Moll, Philip J. W.; Nair, Nityan L.; Helm, Toni; Potter, Andrew C.; Kimchi, Itamar; Vishwanath, Ashvin; Analytis, James G.
2016-07-01
The dispersion of charge carriers in a metal is distinctly different from that of free electrons owing to their interactions with the crystal lattice. These interactions may lead to quasiparticles mimicking the massless relativistic dynamics of high-energy particle physics, and they can twist the quantum phase of electrons into topologically non-trivial knots—producing protected surface states with anomalous electromagnetic properties. These effects intertwine in materials known as Weyl semimetals, and in their crystal-symmetry-protected analogues, Dirac semimetals. The latter show a linear electronic dispersion in three dimensions described by two copies of the Weyl equation (a theoretical description of massless relativistic fermions). At the surface of a crystal, the broken translational symmetry creates topological surface states, so-called Fermi arcs, which have no counterparts in high-energy physics or conventional condensed matter systems. Here we present Shubnikov–de Haas oscillations in focused-ion-beam-prepared microstructures of Cd3As2 that are consistent with the theoretically predicted ‘Weyl orbits’, a kind of cyclotron motion that weaves together Fermi-arc and chiral bulk states. In contrast to conventional cyclotron orbits, this motion is driven by the transfer of chirality from one Weyl node to another, rather than momentum transfer of the Lorentz force. Our observations provide evidence for direct access to the topological properties of charge in a transport experiment, a first step towards their potential application.
Transport evidence for Fermi-arc-mediated chirality transfer in the Dirac semimetal Cd3As2.
Moll, Philip J W; Nair, Nityan L; Helm, Toni; Potter, Andrew C; Kimchi, Itamar; Vishwanath, Ashvin; Analytis, James G
2016-01-01
The dispersion of charge carriers in a metal is distinctly different from that of free electrons owing to their interactions with the crystal lattice. These interactions may lead to quasiparticles mimicking the massless relativistic dynamics of high-energy particle physics, and they can twist the quantum phase of electrons into topologically non-trivial knots-producing protected surface states with anomalous electromagnetic properties. These effects intertwine in materials known as Weyl semimetals, and in their crystal-symmetry-protected analogues, Dirac semimetals. The latter show a linear electronic dispersion in three dimensions described by two copies of the Weyl equation (a theoretical description of massless relativistic fermions). At the surface of a crystal, the broken translational symmetry creates topological surface states, so-called Fermi arcs, which have no counterparts in high-energy physics or conventional condensed matter systems. Here we present Shubnikov-de Haas oscillations in focused-ion-beam-prepared microstructures of Cd3As2 that are consistent with the theoretically predicted 'Weyl orbits', a kind of cyclotron motion that weaves together Fermi-arc and chiral bulk states. In contrast to conventional cyclotron orbits, this motion is driven by the transfer of chirality from one Weyl node to another, rather than momentum transfer of the Lorentz force. Our observations provide evidence for direct access to the topological properties of charge in a transport experiment, a first step towards their potential application. PMID:27376477
Wisman, Ronald V.; Vries, Johannes G. de; Deelman, Berth-Jan; Heeres, Hero J.
2006-01-01
The overall kinetics of the asymmetric transfer hydrogenation of acetophenone to 1-phenyl-ethanol using a Noyori-type homogeneous Ru-catalyst with a chiral amino-alcohol ligand ((1R, 2S)-(+)- cis-1-amino-2- indanol) were determined in a batch reactor with on-line FT-IR spectroscopy. Data analysis sh
ZHU Jin; MA Ya-Ping; LIU Hui; CHEN Li; CUI Xin; DENG Jin-Gen
2003-01-01
@@ As a consequence of the increasing demand for atom economy and environmental friendly methods, the water soluble ligands and their metal complexes are of great interest in catalytic synthesis because of simpler product sepa ration and the possibility of recycling. [1] Unique reactivity and selectivity are often observed in aqueous reactions. [2]Recently, we have developed a new water-soluble chiral vicinal diamine and synthesized its mono-N-tosylated derivative for the first time. The application of its mono-N-tosylated derivative in catalytic asymmetric transfer hydrogenation of prochiral ketones was examined in aqueous media. High activity (up to ＞ 99 % conv. ) and good enatioselectivity ( up to 98% ee ) were achieved for most of prochiral aromatic ketones in organic solvent free system. [3
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...... molecules down to 3%. The microscopic mechanism for the observed chiral induction is suggested to involve nucleation of the intrinsically chiral seeds, allowing for effective transfer and amplification of chirality to large numbers of soldier target molecules....
Huang, Huayin; Zong, Hua; Bian, Guangling; Song, Ling
2015-12-18
Using a single chiral phosphoramide-Zn(II) complex as the catalyst, the asymmetric β-H transfer reduction of aromatic α-trifluoromethyl ketones and enantioselective addition of aromatic aldehydes with Et2Zn in one pot were successfully realized, affording the corresponding additive products of secondary alcohols in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee) and the reduction products of α-trifluoromethyl alcohols in good to excellent yields with up to 77% ee. PMID:26579727
Makó, Attila; Menyhárd, Dóra K.; Bakó, Péter; Keglevich, György; Tőke, László
2008-12-01
The synthesis of a novel, optically active crown ether derived from α- D-altropyranoside is described. A significantly different asymmetric induction was generated by the α- D-glucopyranoside-, α- D-mannopyranoside- and α- D-altropyranoside-based chiral crown catalysts in the epoxidation of trans-chalcone with tert-butyl hydroperoxide under phase-transfer catalytic conditions. It was shown that absolute configuration of the crown-ring fused carbon atoms of the monosaccharides has a great impact on the enantioselectivity. The asymmetric induction could be well explained by considering the possible mechanistic pathway. Molecular modeling (MCMM) and subsequent DFT calculations - in accordance with the experimental results - indicate that the use of glucopyranoside-based catalyst 1 and that of mannopyranoside-based crown ether 2 results in the preferred formation of the opposite antipodes (2 R,3 S and 2 S,3 R, respectively) of the corresponding epoxyketone. At the same time, practically no asymmetric induction was proved if altropyranoside-based crown 3 is applied as the catalyst. The computational results are in qualitative agreement with the experimental data.
Aparecida M. Kawamoto
2002-11-01
Full Text Available A rapid, expedient and enantioselective method for the synthesis of beta-hydroxy amines and monosubstituted aziridines in up to 99% e.e., via asymmetric transfer hydrogenation of a-amino ketones and cyclisation through treatment with tosyl chloride and base, is described. (1R,2R-N-(para-toluenesulfonyl-1,2-ethylenediamine with formic acid has been utilised as a ligand for the Ruthenium (II catalysed enantioselective transfer hydrogenation of the ketones.The chiral 2-methyl aziridine, which is a potentially more efficient bonding agent for Rocket Solid Propellant has been successfully achieved.
Cheetham, Caroline A; Massey, Richard S; Pira, Silvain L; Pritchard, Robin G; Wallace, Timothy W
2011-03-21
5-Substituted 6,7-dihydrodibenz[c,e]azepines, a class of secondary amine incorporating a centre-axis chirality relay, are accessible from 1-substituted N-(2-bromobenzyl)-1-phenylmethanamines via N-acylation and ring-closing intramolecular direct arylation. The ring closure proceeds with high atropodiastereoselectivity due to strain effects that are induced by trigonalisation of the nitrogen atom, as predicted using molecular mechanics calculations. PMID:21267501
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
Kharzeev, Dmitri E.; Yee, Ho-Ung
2012-01-01
We consider the properties of electric circuits involving Weyl semimetals. The existence of the anomaly-induced chiral magnetic current in a Weyl semimetal subjected to magnetic field causes an interesting and unusual behavior of such circuits. We consider two explicit examples: i) a circuit involving the "chiral battery" and ii) a circuit that can be used as a "quantum amplifier" of magnetic field. The unique properties of these circuits stem from the chiral anomaly and may be utilized for c...
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.
Montalvo-Gonzalez, Ruben [Universidad Autonoma de Nayarit, Tepic, Nay (Mexico). Unidad Academica de Ciencias Quimico Biologicas y Farmaceuticas; Chavez, Daniel; Aguirre, Gerardo; Parra-Hake, Miguel; Somanathan, Ratnasamy, E-mail: somanatha@sundown.sdsu.ed [Instituto Tecnologico de Tijuana, B.C. (Mexico). Centro de Graduados e Investigacion
2010-07-01
Two C{sub 2}-symmetric bis(sulfonamide) ligands containing fluorene-chiral (1R, 2R)-cyclohexane-1,2-diamine were complexed to Rh{sup III}(Cp{sup *}) and used as catalyst to reduce aromatic ketones. The corresponding chiral secondary alcohols were obtained in 87-100% ee and 85-99% yield, under asymmetric transfer hydrogenation (ATH) conditions using aqueous sodium formate as the hydride source. With acetophenone, 94% ee and 86-97% yield was achieved with substrate/catalyst (S/C) ratio of 10,000. (author)
Dietiker, P.; Miloglyadov, E.; Quack, M., E-mail: Martin@Quack.ch; Schneider, A.; Seyfang, G. [Physical Chemistry, ETH Zürich, CH-8093 Zürich (Switzerland)
2015-12-28
We have set up an experiment for the efficient population transfer by a sequential two photon—absorption and stimulated emission—process in a molecular beam to prepare quantum states of well defined parity and their subsequent sensitive detection. This provides a proof of principle for an experiment which would allow for parity selection and measurement of the time evolution of parity in chiral molecules, resulting in a measurement of the parity violating energy difference Δ{sub pv}E between enantiomers of chiral molecules. Here, we present first results on a simple achiral molecule demonstrating efficient population transfer (about 80% on the average for each step) and unperturbed persistence of a selected excited parity level over flight times of about 1.3 ms in the beam. In agreement with model calculations with and without including nuclear hyperfine structure, efficient population transfer can be achieved by a rather simple implementation of the rapid adiabatic passage method of Reuss and coworkers and considering also the stimulated Raman adiabatic passage technique of Bergmann and coworkers as an alternative. The preparation step uses two powerful single mode continuous wave optical parametric oscillators of high frequency stability and accuracy. The detection uses a sensitive resonantly enhanced multiphoton ionization method after free flight lengths of up to 0.8 m in the molecular beam. Using this technique, we were able to also resolve the nuclear hyperfine structure in the rovibrational levels of the ν{sub 1} and ν{sub 3} fundamentals as well as the 2ν{sub 4} overtone of {sup 14}NH{sub 3}, for which no previous data with hyperfine resolution were available. We present our new results on the quadrupole coupling constants for the ν{sub 1}, ν{sub 3}, and 2ν{sub 4} levels in the context of previously known data for ν{sub 2} and its overtone, as well as ν{sub 4}, and the ground state. Thus, now, {sup 14}N quadrupole coupling constants for all
We have set up an experiment for the efficient population transfer by a sequential two photon—absorption and stimulated emission—process in a molecular beam to prepare quantum states of well defined parity and their subsequent sensitive detection. This provides a proof of principle for an experiment which would allow for parity selection and measurement of the time evolution of parity in chiral molecules, resulting in a measurement of the parity violating energy difference ΔpvE between enantiomers of chiral molecules. Here, we present first results on a simple achiral molecule demonstrating efficient population transfer (about 80% on the average for each step) and unperturbed persistence of a selected excited parity level over flight times of about 1.3 ms in the beam. In agreement with model calculations with and without including nuclear hyperfine structure, efficient population transfer can be achieved by a rather simple implementation of the rapid adiabatic passage method of Reuss and coworkers and considering also the stimulated Raman adiabatic passage technique of Bergmann and coworkers as an alternative. The preparation step uses two powerful single mode continuous wave optical parametric oscillators of high frequency stability and accuracy. The detection uses a sensitive resonantly enhanced multiphoton ionization method after free flight lengths of up to 0.8 m in the molecular beam. Using this technique, we were able to also resolve the nuclear hyperfine structure in the rovibrational levels of the ν1 and ν3 fundamentals as well as the 2ν4 overtone of 14NH3, for which no previous data with hyperfine resolution were available. We present our new results on the quadrupole coupling constants for the ν1, ν3, and 2ν4 levels in the context of previously known data for ν2 and its overtone, as well as ν4, and the ground state. Thus, now, 14N quadrupole coupling constants for all fundamentals and some overtones of 14NH3 are known and can be used for
Dietiker, P; Miloglyadov, E; Quack, M; Schneider, A; Seyfang, G
2015-12-28
We have set up an experiment for the efficient population transfer by a sequential two photon-absorption and stimulated emission-process in a molecular beam to prepare quantum states of well defined parity and their subsequent sensitive detection. This provides a proof of principle for an experiment which would allow for parity selection and measurement of the time evolution of parity in chiral molecules, resulting in a measurement of the parity violating energy difference ΔpvE between enantiomers of chiral molecules. Here, we present first results on a simple achiral molecule demonstrating efficient population transfer (about 80% on the average for each step) and unperturbed persistence of a selected excited parity level over flight times of about 1.3 ms in the beam. In agreement with model calculations with and without including nuclear hyperfine structure, efficient population transfer can be achieved by a rather simple implementation of the rapid adiabatic passage method of Reuss and coworkers and considering also the stimulated Raman adiabatic passage technique of Bergmann and coworkers as an alternative. The preparation step uses two powerful single mode continuous wave optical parametric oscillators of high frequency stability and accuracy. The detection uses a sensitive resonantly enhanced multiphoton ionization method after free flight lengths of up to 0.8 m in the molecular beam. Using this technique, we were able to also resolve the nuclear hyperfine structure in the rovibrational levels of the ν1 and ν3 fundamentals as well as the 2ν4 overtone of (14)NH3, for which no previous data with hyperfine resolution were available. We present our new results on the quadrupole coupling constants for the ν1, ν3, and 2ν4 levels in the context of previously known data for ν2 and its overtone, as well as ν4, and the ground state. Thus, now, (14)N quadrupole coupling constants for all fundamentals and some overtones of (14)NH3 are known and can be used for
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 ...
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.
Gleiser, Marcelo; Thorarinson, Joel; Walker, Sara Imari
2008-12-01
Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively L-amino acids, while only D-sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high intensity and long duration events may drive achiral initial conditions towards chirality. We argue that life’s homochirality resulted from sequential chiral symmetry breaking triggered by environmental events, thus extending the theory of punctuated equilibrium to the prebiotic realm. Applying our arguments to other potentially life-bearing planetary platforms, we predict that a statistically representative sampling will be racemic on average.
Gleiser, Marcelo; Walker, Sara Imari
2008-01-01
Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively levorotatory (L) amino acids, while only dextrorotatory (R) sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high intensity and long duration events may drive achiral initial conditions towards chirality. We argue that life's homochirality resulted from sequential chiral symmetry breaking triggered by environmental events, thus extending the theory of punctuated equilibrium to the prebiotic realm. Applying our arguments to other potentially life-bearing planetary platforms, we predict that a statistically representative sampling will be racemic on average.
Chang, N P
1994-01-01
Chiral symmetry undergoes a metamorphosis at T.sub(c). For T < T.sub(c), the usual Noether charge, \\Qa, is dynamically broken by the vacuum. Above T.sub(c), chiral symmetry undergoes a subtle change, and the Noether charge \\underline{{\\em morphs}} into \\Qbeta, with the thermal vacuum now becoming invariant under \\Qbeta. This vacuum is however not invariant under the old \\Qa transformations. As a result, the pion remains strictly massless at high T. The pion propagates in the early universe with a halo. New order parameters are proposed to probe the structure of the new thermal vacuum.
Chiral Nanoscience and Nanotechnology
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...
We present many varied chiral symmetry models at the quark level which consistently describe strong interaction hadron dynamics. The pattern that emerges is a nonstrange current quark mass scale mcur ≅ (34-69) MeV and a current quark mass ratio (ms/m)cur ≅ 5-6 along with no strange quark content in nucleons. (orig./WL)
Gleiser, Marcelo; Thorarinson, Joel; Walker, Sara Imari
2008-01-01
Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively levorotatory (L) amino acids, while only dextrorotatory (R) sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high int...
Zou, Dandan; Cao, Xin [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Lu, Xinpei, E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Ostrikov, Kostya [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000 (Australia); Comonwealth Scientific and Industrial Research Organization, P.O. Box 218, Sydney, New South Wales 2070 (Australia)
2015-10-15
The interaction of time-varying electromagnetic fields and solid, liquid, and gaseous matter may lead to electrical breakdown phenomena through the excitation of ionization waves or streamers that control the dynamics of localized plasma propagation through the media. The streamers usually propagate along straight lines, either between random points in space or along a certain direction in a guided mode. Here, we report on a new type of plasma discharges with the regular helical propagation pattern driven by a pulsed dc voltage in nitrogen at sub-atmospheric-pressure conditions. The helical guided streamers, named chiral streamers or chi-streamers, are excited without any external magnetic fields, which commonly cause helical plasma motions. We also demonstrate a hybrid propagation mode involving the interchangeable chiral streamers and the straight-line propagating plasmas. High-speed, time-resolved optical imaging reveals that the chiral streamers and the hybrid patterns are made of spatially localized discrete plasma bullets, similar to the straight-line guided streamers. These results may enable effective control of propagation of confined plasmas and electromagnetic energy along pre-determined, potentially deterministic paths, which have important implications for the development of next-generation plasma-based radiation sources, communication devices, and medical treatments.
Zou, Dandan; Cao, Xin; Lu, Xinpei; Ostrikov, Kostya Ken
2015-10-01
The interaction of time-varying electromagnetic fields and solid, liquid, and gaseous matter may lead to electrical breakdown phenomena through the excitation of ionization waves or streamers that control the dynamics of localized plasma propagation through the media. The streamers usually propagate along straight lines, either between random points in space or along a certain direction in a guided mode. Here, we report on a new type of plasma discharges with the regular helical propagation pattern driven by a pulsed dc voltage in nitrogen at sub-atmospheric-pressure conditions. The helical guided streamers, named chiral streamers or chi-streamers, are excited without any external magnetic fields, which commonly cause helical plasma motions. We also demonstrate a hybrid propagation mode involving the interchangeable chiral streamers and the straight-line propagating plasmas. High-speed, time-resolved optical imaging reveals that the chiral streamers and the hybrid patterns are made of spatially localized discrete plasma bullets, similar to the straight-line guided streamers. These results may enable effective control of propagation of confined plasmas and electromagnetic energy along pre-determined, potentially deterministic paths, which have important implications for the development of next-generation plasma-based radiation sources, communication devices, and medical treatments.
New Chiral Metal Cluster Systems for Catalytic Asymmetric Syntheses of Chiral Alcohols
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.
Chiral geometry in multiple chiral doublet bands
Zhang, Hao
2015-01-01
The chiral geometry of the multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters $\\gamma$ in the particle rotor model with $\\pi h_{11/2}\\otimes \
Chiral symmetry and chiral-symmetry breaking
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
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.
Chiral dynamics of baryons in the perturbative chiral quark model
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
Chiral Gravitational Waves from Chiral Fermions
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.
Atroposelective Synthesis of Axially Chiral Thiohydantoin Derivatives.
Sarigul, Sevgi; Dogan, Ilknur
2016-07-15
Nonracemic axially chiral thiohydantoins were synthesized atroposelectively by the reaction of o-aryl isothiocyanates with amino acid ester salts in the presence of triethylamine (TEA). The synthesis of the nonaxially chiral derivatives, however, gave thiohydantoins racemized at C-5 of the heterocyclic ring. The micropreparatively resolved enantiomers of the nonaxially chiral derivatives from the racemic products were found to be optically stable under neutral conditions. On formation of the 5-methyl-3-arylthiohydantoin ring, bulky o-aryl substituents at N3 were found to suppress the C-5 racemization and in this way enabled the transfer of chirality from the α-amino acid to the products. The corresponding 5-isopropylthiohydantoins turned out to be more prone to racemization at C-5 during the ring formation. The isomer compositions of the synthesized axially chiral thiohydantoins have been determined through HPLC analyses with chiral stationary phases. In most cases a high prevalence of the P isomers over the M isomers has been obtained. The barriers to rotation determined around the Nsp(2)-Caryl chiral axis were found to be dependent upon the size of the o-halo aryl substituents. PMID:27322739
Anomalous Chiral Superfluidity
Lublinsky, Michael(Physics Department, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel); Zahed, Ismail
2009-01-01
We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavour 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 ...
Introduction to chiral symmetry
These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented
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.
Chirally enhanced solubilization through perylene-based surfactant
Recently we introduced a rationally designed surfactant which forms energy transfer complexes with carbon nanotubes. We investigate the chiral selectivity of this compound, a perylene derived surfactant, through photoluminescence (PL) measurements, and find a strong enhancement of the luminescence intensity for one particular group of chiralities. The effect is striking, with luminescence increases of several hundred percent. Chiral selectivity of the investigated surfactant compound as compared to solubilization through sodium cholate (SC). Small numbers indicate chirality, large numbers laola family. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Chirally enhanced solubilization through perylene-based surfactant
Ernst, Friederike; Reich, Stephanie; Setaro, Antonio [Department of Physics, Freie Universitaet Berlin, Arnimallee 14, 14195 Berlin (Germany); Heek, Timm; Haag, Rainer [Department of Chemistry, Freie Universitaet Berlin, Takustrasse 3, 14195 Berlin (Germany)
2012-12-15
Recently we introduced a rationally designed surfactant which forms energy transfer complexes with carbon nanotubes. We investigate the chiral selectivity of this compound, a perylene derived surfactant, through photoluminescence (PL) measurements, and find a strong enhancement of the luminescence intensity for one particular group of chiralities. The effect is striking, with luminescence increases of several hundred percent. Chiral selectivity of the investigated surfactant compound as compared to solubilization through sodium cholate (SC). Small numbers indicate chirality, large numbers laola family. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Haupert, Levi M.; Simpson, Garth J.
2009-05-01
The past decade has witnessed the emergence of new measurement approaches and applications for chiral thin films and materials enabled by the observations of the high sensitivity of second-order nonlinear optical measurements to chirality. In thin films, the chiral response to second harmonic generation and sum frequency generation (SFG) from a single molecular monolayer is often comparable with the achiral response. The chiral specificity also allows for symmetry-allowed SFG in isotropic chiral media, confirming predictions made ˜50 years ago. With these experimental demonstrations in hand, an important challenge is the construction of intuitive predictive models that allow the measured chiral response to be meaningfully related back to molecular and macromolecular structure. This review defines and considers three distinct mechanisms for chiral effects in uniaxially oriented assemblies: orientational chirality, intrinsic chirality, and isotropic chirality. The role of each is discussed in experimental and computational studies of bacteriorhodopsin films, binaphthol, and collagen. Collectively, these three model systems support a remarkably simple framework for quantitatively recovering the measured chiral-specific activity.
Chiral Rotational Spectroscopy
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.
On chiral and non chiral 1D supermultiplets
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)
Chiral symmetry and chiral-symmetry breaking
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)
Chiral two-body currents in nuclei: Gamow-Teller transitions and neutrinoless double-beta decay
Menéndez, J.; Gazit, D.; Schwenk, A.
2011-01-01
We show that chiral effective field theory (EFT) two-body currents provide important contributions to the quenching of low-momentum-transfer Gamow-Teller transitions, and use chiral EFT to predict the momentum-transfer dependence that is probed in neutrinoless double-beta decay. We then calculate for the first time the neutrinoless double-beta decay operator based on chiral EFT currents and study the nuclear matrix elements at successive orders. The contributions from chiral two-body currents...
Understanding complex chiral plasmonics
Duan, Xiaoyang; Yue, Song; Liu, Na
2015-10-01
Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the `host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant and simple analytical model, which can describe, predict, and comprehend the chiroptical spectra in detail. Our study will shed light on designing well-controlled chiral-achiral coupling platforms for reliable chiral sensing.Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the `host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant
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.
Mechanical separation of chiral dipoles by chiral light
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.
Doped Chiral Polymer Metamaterials Project
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...
Teleporting Superpositions of Chiral Amplitudes
Maierle, C S; Harris, R A; Maierle, Christopher S.; Lidar, Daniel A.; Harris, Robert A.
1998-01-01
Chiral molecules may exist in superpositions of left- and right-handed states. We show how the amplitudes of such superpositions may be teleported to the polarization degrees of freedom of a photon. Two experimental schemes are proposed, one leading to perfect, the other to state-dependent teleportation. Both methods yield complete information about the amplitudes. This is the first explicit example of "inter-species" teleportation, where the amplitudes of the quantum superposition of one species are transferred at the end of the process to a different species. The latter is then easily accessible for measurement.
Chiral geometry in multiple chiral doublet bands
Zhang, Hao; Chen, Qibo
2016-02-01
The chiral geometry of multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters γ in the particle rotor model with . The energy spectra, electromagnetic transition probabilities B(M1) and B(E2), angular momenta, and K-distributions are studied. It is demonstrated that the chirality still remains not only in the yrast and yrare bands, but also in the two higher excited bands when γ deviates from 30°. The chiral geometry relies significantly on γ, and the chiral geometry of the two higher excited partner bands is not as good as that of the yrast and yrare doublet bands. Supported by Plan Project of Beijing College Students’ Scientific Research and Entrepreneurial Action, Major State 973 Program of China (2013CB834400), National Natural Science Foundation of China (11175002, 11335002, 11375015, 11461141002), National Fund for Fostering Talents of Basic Science (NFFTBS) (J1103206), Research Fund for Doctoral Program of Higher Education (20110001110087) and China Postdoctoral Science Foundation (2015M580007)
In this paper, Lorentzian wormholes with a phantom field and chiral matter fields have been obtained. In addition, it is shown that for different values of the gravitational coupling of the chiral fields, the wormhole geometry changes. Finally, the stability of the corresponding wormholes is studied and it is shown that are unstable (eg. Ellis's wormhole instability)
Spectral signatures of chirality
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...
Chiral Magnetic "Superfluidity"
Sadofyev, Andrey V
2015-01-01
We study a heavy impurity moving longitudinal with the direction of an external magnetic field in an anomalous chiral medium. Such system would carry a non-dissipative current of chiral magnetic effect associated with the anomaly. We show, by generalizing Landau's criterion for superfluidity, that the "anomalous component" which gives rise to the anomalous transport will {\\it not} contribute to the drag experienced by an impurity. We argue on very general basis that those systems with a strong magnetic field would exhibit the behavior of 'superfluidity" -- the motion of the heavy impurity is frictionless, in analog to the case of a superfluid. However, this "superfluidity" exists even for chiral media at finite temperature and only in the directional longitudinal with the magnetic field, in contrast to the ordinary superfluid. We will call this novel phenomenon as the Chiral Magnetic "Superfluidity". We demonstrate and confirm our general results with two complementary examples: weakly coupled chiral fermion ...
Chiral Magnetic Effect and Chiral Phase Transition
FU Wei-Jie; LIU Yu-Xin; WU Yue-Liang
2011-01-01
We study the influence of the chiral phase transition on the chiral magnetic effect.The azimuthal chargeparticle correlations as functions of the temperature are calculated.It is found that there is a pronounced cusp in the correlations as the temperature reaches its critical value for the QCD phase transition.It is predicted that there will be a drastic suppression of the charge-particle correlations as the collision energy in RHIC decreases to below a critical value.We show then the azimuthal charge-particle correlations can be the signal to identify the occurrence of the QCD phase transitions in RHIC energy scan experiments.
Magnetic fields and chiral asymmetry in the early hot universe
Sidorenko, Maxim; Shtanov, Yuri
2016-01-01
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...
Chiral String-Soliton Model for the light chiral baryons
Pavlovsky, Oleg
2010-01-01
The Chiral String-Soliton Model is a joining of the two notions about the light chiral baryons: the chiral soliton models (like the Skyrme model) and the Quark-Gluon String models. The ChSS model is based on the Effective Chiral Lagrangian which was proposed in [arXiv:hep-ph/0306216]. We have studied the physical properties of the light chiral baryon within the framework of this ChSS model.
Applications of chiral symmetry
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 Tχ implies that the ρ and a1 vector mesons are degenerate in mass. In a gauged linear sigma model the ρ mass increases with temperature, mρ(Tχ) > mρ(0). The author conjectures that at Tχ the thermal ρ - a1, peak is relatively high, at about ∼1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The ω meson also increases in mass, nearly degenerate with the ρ, but its width grows dramatically with temperature, increasing to at least ∼100 MeV by Tχ. 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 quenchedclose 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
Chiral supergravity and anomalies
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.
Synthesis of Chiral Cyclopentenones.
Simeonov, Svilen P; Nunes, João P M; Guerra, Krassimira; Kurteva, Vanya B; Afonso, Carlos A M
2016-05-25
The cyclopentenone unit is a very powerful synthon for the synthesis of a variety of bioactive target molecules. This is due to the broad diversity of chemical modifications available for the enone structural motif. In particular, chiral cyclopentenones are important precursors in the asymmetric synthesis of target chiral molecules. This Review provides an overview of reported methods for enantioselective and asymmetric syntheses of cyclopentenones, including chemical and enzymatic resolution, asymmetric synthesis via Pauson-Khand reaction, Nazarov cyclization and organocatalyzed reactions, asymmetric functionalization of the existing cyclopentenone unit, and functionalization of chiral building blocks. PMID:27101336
Catalysis of Dynamical Chiral Symmetry Breaking by Chiral Chemical Potential
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.
Probing chirality fluctuations in molecules by nonlinear optical spectroscopy
Mann, N; Mukamel, S; Thorwart, M
2014-01-01
Symmetry breaking caused by geometric fluctuations can enable processes that are otherwise forbidden. An example is a perylene bisimide dyad whose dipole moments are perpendicular to each other. F\\"orster-type energy transfer is thus forbidden at the equilibrium geometry since the dipolar coupling vanishes. Yet, fluctuations of the geometric arrangement have been shown to induce finite energy transfer that depends on the dipole variance, rather than the mean. We demonstrate an analogous effect associated with chirality symmetry breaking. In its equilibrium geometry this dimer is non chiral. The linear chiral response which depends on the average geometry thus vanishes. However, we show that certain 2D chiral optical signals are finite due to geometric fluctuations. Furthermore, the correlation time of these fluctuations can be experimentally revealed by the waiting time dependence of the 2D signal.
Quantum-mechanical picture of peripheral chiral dynamics
Granados, Carlos [Uppsala Univ., Uppsala (Sweden); Weiss, Christian [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2015-08-28
The nucleon's peripheral transverse charge and magnetization densities are computed in chiral effective field theory. The densities are represented in first-quantized form, as overlap integrals of chiral light-front wave functions describing the transition of the nucleon to soft pion-nucleon intermediate states. The orbital motion of the pion causes a large left-right asymmetry in a transversely polarized nucleon. As a result, the effect attests to the relativistic nature of chiral dynamics [pion momenta k = O(M_{π})] and could be observed in form factor measurements at low momentum transfer.
Xavier Sala-i-Martin
1992-01-01
In this paper I develop a positive theory of intergenerational transfers. I argue that transfers are a means to induce retirement. that is, to buy the elderly out of the labor force. The reason why societies choose to do such a thing is that aggregate output is higher if the elderly do not work. I model this idea through positive externalities in the average stock of human capital: because skills depreciate with age. one implication of these externalities is that the elderly have a negative e...
Bonner, W.A. [Department of Chemistry Stanford University, Stanford, California 94305 (United States)
1996-07-01
The indispensable role played by homochirality and chiral homogeneity in the self-replication of crucial biomolecules is stressed, with the conclusion that life could neither exist nor originate without these chiral molecular attributes. Hypotheses historically proposed for the origin of chiral molecules on Earth are reviewed, including biogenic theories as well as abiotic theories embracing both indeterminate and determinate mechanisms. Indeterminate mechanisms, including autocatalytic symmetry breaking, asymmetric adsorption on quartz and clay minerals, and asymmetric syntheses in chiral crystals, are discussed and evaluated in the context of the prebiotic environment. Abiotic determinate mechanisms based on electric, magnetic and gravitational fields, on circularly polarized light (CPL), and on parity violation effects are summarized, with the emphasis that only CPL has proved practicable experimentally, but that it would be implausible on the primitive Earth. Mechanisms for the amplification of small, indigenous enantiomeric excesses are discussed, with one involving the partial polymerization of amino acids and the partial hydrolysis of polypeptides suggested as potentially viable prebiotically. Aspects of the turbulent, chirality-destructive primeval environment are described, with the conclusion that all of the above mechanisms for the {ital terrestrial} prebiotic origin of chirality would be non-viable, and that an alternative extraterrestrial source for the accumulation of chiral molecules on primitive Earth must have been operative. A scenario for this is outlined, in which we postulate that asymmetric photolysis of the organic mantles on interstellar grains in molecular clouds by circularly polarized ultraviolet synchrotron radiation from the neutron star remnants of supernovae produces chiral molecules in the grain mantles. (Abstract Truncated)
Chiral separation in microflows
Kostur, Marcin; Schindler, Michael; Talkner, Peter; Hänggi, Peter
2005-01-01
Molecules that only differ by their chirality, so called enantiomers, often possess different properties with respect to their biological function. Therefore, the separation of enantiomers presents a prominent challenge in molecular biology and belongs to the ``Holy Grail'' of organic chemistry. We suggest a new separation technique for chiral molecules that is based on the transport properties in a microfluidic flow with spatially variable vorticity. Because of their size the thermal fluctua...
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.
Spontaneous transmission of chirality through multiple length scales.
Iski, Erin V; Tierney, Heather L; Jewell, April D; Sykes, E Charles H
2011-06-20
The hierarchical transfer of chirality in nature, from the nano-, to meso-, to macroscopic length scales, is very complex, and as of yet, not well understood. The advent of scanning probes has allowed chirality to be monitored at the single molecule or monolayer level and has opened up the possibility to track enantiospecific interactions and chiral self-assembly with molecular-scale detail. This paper describes the self-assembly of a simple, model molecule (naphtho[2,3-a]pyrene) that is achiral in the gas phase, but becomes chiral when adsorbed on a surface. This polyaromatic hydrocarbon forms a stable and reversibly ordered system on Cu(111) in which the transmission of chirality from single surface-bound molecules to complex 2D chiral architectures can be monitored as a function of molecular packing density and surface temperature. In addition to the point chirality of the surface-bound molecule, the unit cell of the molecular domains was also found to be chiral due to the incommensurate alignment of the molecular rows with respect to the underlying metal lattice. These molecular domains always aggregated in groups of three, all of the same chirality, but with different rotational orientations, forming homochiral "tri-lobe" ensembles. At a larger length scale, these tri-lobe ensembles associated with nearest-neighbor tri-lobe units of opposite chirality at lower packing densities before forming an extended array of homochiral tri-lobe ensembles at higher converges. This system displayed chirality at a variety of size scales from the molecular (≈1 nm) and domain (≈5 nm) to the tri-lobe ensemble (≈10 nm) and extended array (>25 nm) levels. The chirality of the tri-lobe ensembles dictated how the overall surface packing occurred and both homo- and heterochiral arrays could be reproducibly and reversibly formed and interchanged as a function of surface coverage. Finally, these chirally templated surfaces displayed remarkable enantiospecificity for
Dirac brackets for the chiral Schwinger model with chiral constraint
Dirac brackets for the chiral Schwinger model with chiral constraint are derived perturbatively from the correlation function by the BJL limit method. The results show that the Poissons brackets are not consistent in this theory. (author)
Chirality has recently been proposed as a novel feature of rotating nuclei [1]. Because the chiral symmetry is dichotomic, its spontaneous breaking by the axial angular momentum vector leads to doublets of closely lying rotational bands of the same parity. To investigate nuclear chirality, next to establish the existence of almost degenerate rotational bands, it is necessary to measure also other observables and compare them to the model predictions. The crucial test for the suggested nuclei as candidates to express chirality is based on precise lifetime measurements. Two lifetime experiments and theoretical approaches for the description of the experimental results will be presented. Lifetimes of exited states in 134Pr were measured [2,3] by means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The branching ratios and the electric or magnetic character of the transitions were also investigated [3]. The experiments were performed at IReS, Strasbourg, using the EUROBALL IV spectrometer, in conjunction with the inner bismuth germanate ball and the Cologne coincidence plunger apparatus. Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F, 4n)134Pr. The possible chiral interpretation of twin bands was investigated in the two-quasiparticle triaxial rotor [1] and interacting boson-fermion-fermion models [4]. Both theoretical approaches can describe the level-scheme of 134Pr. The analysis of the wave functions has shown that the possibility for the angular momenta of the proton, neutron, and core to find themselves in the favorable, almost orthogonal geometry, is present but is far from being dominant [3,5]. The structure is characterized by large β and γ fluctuations. The existence of doublets of bands in 134Pr can be attributed to weak chirality dominated by shape fluctuations. In a second experiment branching ratios and lifetimes in 136Pm were measured by means of the recoil distance Doppler-shift and
Entwicklung anion-chiraler ionischer Flüssigkeiten und ihre Anwendung in der Katalyse
Gausepohl, Rolf
2006-01-01
The aim of this dissertation was the investigation of anion-chiral ionic liquids (ILs) in catalytic reactions in order to investigate a potential chirality transfer. Thus chirality has been incorporated into the anion of the molten salt. There are several examples of catalytic reactions known in literature to be heavily influenced by the choice of the anions covering a large scope of influence from conversion to even enantioselectivity. It was aimed to combine this effect with the structural ...
Chiral anomalies and differential geometry
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)
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...
Fok, R
2011-01-01
We calculate the two-body decay rates of "quirkonium" states formed from quirks that acquire mass solely through electroweak symmetry breaking. We consider SU(N)_ic infracolor with two flavors of quirks transforming under the electroweak group (but not QCD) of the Standard Model. In one case, the quirks are in a chiral representation of the electroweak group, while in the other case, a vector-like representation. The differences in the dominant decay channels between "chiral quirkonia" versus "vector-like quirkonia" are striking. Several chiral quirkonia states can decay into the unique two-body resonance channels WH, ZH, t\\bar{t}, t\\bar{b} / b\\bar{t}, and gamma+H, which never dominate for vector-like quirkonia. Additionally, the channels WW, WZ, ZZ, and W+gamma, are shared among both chiral and vector-like quirkonia. Resonances of dileptons or light quarks (dijets) can dominate for some vector-like quirkonia states throughout their mass range, while these modes never dominate for chiral quirkonia unless the ...
We calculate the two-body decay rates of quirkonium states formed from quirks that acquire mass solely through electroweak symmetry breaking. We consider SU(N)ic infracolor with two flavors of quirks transforming under the electroweak group (but not QCD) of the standard model. In one case, the quirks are in a chiral representation of the electroweak group, while in the other case, a vectorlike representation. The differences in the dominant decay channels between 'chiral quirkonia' versus 'vectorlike quirkonia' are striking. Several chiral quirkonia states can decay into the unique two-body resonance channels WH, ZH, tt, tb/bt, and γH, which never dominate for vectorlike quirkonia. Additionally, the channels WW, WZ, ZZ, and Wγ, are shared among both chiral and vectorlike quirkonia. Resonances of dileptons or light quarks (dijets) can dominate for some vectorlike quirkonia states throughout their mass range, while these modes never dominate for chiral quirkonia unless the decays into pairs of gauge or Higgs bosons are kinematically forbidden.
Stability of topological defects in chiral superconductors: London theory
This paper examines the thermodynamic stability of chiral domain walls and vortices-topological defects which can exist in chiral superconductors. Using London theory it is demonstrated that at sufficiently small applied and chiral fields the existence of domain walls and vortices in the sample is not favored and the sample's configuration is a single domain. The particular chirality of the single-domain configuration is neither favored nor disfavored by the applied field. Increasing the field leads to an entry of a domain-wall loop or a vortex into the sample. The formation of a straight domain wall is never preferred in equilibrium. Values of the entry (critical) fields for both types of defects, as well as the equilibrium size of the domain-wall loop, are calculated. We also consider a mesoscopic chiral sample and calculate its zero-field magnetization, susceptibility, and a change in the magnetic moment due to a vortex or a domain-wall entry. We show that in the case of a soft domain wall whose energetics is dominated by the chiral current (and not by the surface tension) its behavior in mesoscopic samples is substantially different from that in the bulk case and can be used for a controllable transfer of edge excitations. The applicability of these results to Sr2RuO4 - a tentative chiral superconductor - is discussed.
Chiral Invariance of Massive Fermions
Das, A.(University of Arizona, Tucson, AZ, 85721, USA); Hott, M
1994-01-01
We show that a massive fermion theory, while not invariant under the conventional chiral transformation, is invariant under a $m$-deformed chiral transformation. These transformations and the associated conserved charges are nonlocal but reduce to the usual transformations and charges when $m=0$. The $m$-deformed charges commute with helicity and satisfy the conventional chiral algebra.
Chiral Synthons in Pesticide Syntheses
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
Chiral Electroweak Currents in Nuclei
Riska, D O
2016-01-01
The development of the chiral dynamics based description of nuclear electroweak currents is reviewed. Gerald E. (Gerry) Brown's role in basing theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative examples of the successful description of electroweak observables of light nuclei obtained from chiral effective field theory are presented.
Holographic Chiral Magnetic Spiral
We study the ground state of baryonic/axial matter at zero temperature chiral-symmetry broken phase under a large magnetic field, in the framework of holographic QCD by Sakai-Sugimoto. Our study is motivated by a recent proposal of chiral magnetic spiral phase that has been argued to be favored against previously studied phase of homogeneous distribution of axial/baryonic currents in terms of meson super-currents dictated by triangle anomalies in QCD. Our results provide an existence proof of chiral magnetic spiral in strong coupling regime via holography, at least for large axial chemical potentials, whereas we don't find the phenomenon in the case of purely baryonic chemical potential. (author)
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...
Chiral control of electron transmission through molecules.
Skourtis, Spiros S; Beratan, David N; Naaman, Ron; Nitzan, Abraham; Waldeck, David H
2008-12-01
Electron transmission through chiral molecules induced by circularly polarized light can be very different for mirror-image structures, a peculiar fact given that the electronic energy spectra of the systems are identical. We propose that this asymmetry--as large as 10% for resonant transport--arises from different dynamical responses of the mirrored structures to coherent excitation. This behavior is described in the context of a general novel phenomenon of current transfer (transfer of charge with its momentum information) and accounts for the observed asymmetry and its dependence on structure. PMID:19113598
Baryon chiral perturbation theory
We provide a short introduction to the one-nucleon sector of chiral perturbation theory and address the issue of power counting and renormalization. We discuss the infrared regularization and the extended on-mass-shell scheme. Both allow for the inclusion of further degrees of freedom beyond pions and nucleons and the application to higher-loop calculations. As applications we consider the chiral expansion of the nucleon mass to order O(q6) and the inclusion of vector and axial-vector mesons in the calculation of nucleon form factors. Finally, we address the complex-mass scheme for describing unstable particles in effective field theory.
Baryon chiral perturbation theory
Scherer, Stefan
2011-01-01
We provide a short introduction to the one-nucleon sector of chiral perturbation theory and address the issue of power counting and renormalization. We discuss the infrared regularization and the extended on-mass-shell scheme. Both allow for the inclusion of further degrees of freedom beyond pions and nucleons and the application to higher-loop calculations. As applications we consider the chiral expansion of the nucleon mass to order ${\\cal O}(q^6)$ and the inclusion of vector and axial-vector mesons in the calculation of nucleon form factors. Finally, we address the complex-mass scheme for describing unstable particles in effective field theory.
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.
Baryon chiral perturbation theory
Scherer, S.
2012-03-01
We provide a short introduction to the one-nucleon sector of chiral perturbation theory and address the issue of power counting and renormalization. We discuss the infrared regularization and the extended on-mass-shell scheme. Both allow for the inclusion of further degrees of freedom beyond pions and nucleons and the application to higher-loop calculations. As applications we consider the chiral expansion of the nucleon mass to order Script O(q6) and the inclusion of vector and axial-vector mesons in the calculation of nucleon form factors. Finally, we address the complex-mass scheme for describing unstable particles in effective field theory.
After a general introduction to the structure of effective field theories, the main ingredients of chiral perturbation theory are reviewed. Applications include the light quark mass ratios and pion-pion scattering to two-loop accuracy. In the pion-nucleon system, the linear σ model is contrasted with chiral perturbation theory. The heavy-nucleon expansion is used to construct the effective pion-nucleon Lagrangian to third order in the low-energy expansion, with applications to nucleon Compton scattering. (author)
Chiral Heat Wave and wave mixing in chiral media
Chernodub, M N
2016-01-01
We show that a hot rotating fluid of relativistic chiral fermions possesses a new gapless collective excitation associated with coherent propagation of energy density and chiral density waves along the axis of rotation. This excitation, 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. 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. We also demonstrate that rotating chiral systems subjected to external magnetic field possess non-propagating metastable thermal excitations, the Dense Hot Spots.
Chiral forces and molecular dissymmetry
Chiral molecules leading to helical macromolecules seem to preserve information and extend it better. In the biological world RNA is the very paradigm for self-replication, elongation and autocatalytic editing. The nucleic acid itself is not chiral. It acquires its chirality by association with D-sugars. Although the chiral information or selectivity put in by the unit monomer is no longer of much interest to the biologists - they tend to leave it to the Darwinian selection principle to take care of it as illustrated by Frank's model - it is vital to understand the origin of chirality. There are three different approaches for the chiral origin of life: (1) Phenomenological, (2) Electromagnetic molecular and Coriolis forces and (3) Atomic or nuclear force, the neutral weak current. The phenomenological approach involves spontaneous symmetry breaking fluctuations in far for equilibrium systems or nucleation and crystallization. Chance plays a major role in the chiral molecule selected
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...
Chiral Biomarkers in Meteorites
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
Tsai, J.-C.; Ye, Fangfu; Rodriguez, Juan; Gollub, J. P.; Lubensky, T. C.
2005-05-01
Inspired by rattleback toys, we created small chiral wires that rotate in a preferred direction on a vertically oscillating platform and quantified their motion with experiment and simulation. We demonstrate experimentally that angular momentum of rotation about particle centers of mass is converted to collective angular momentum of center-of-mass motion in a granular gas of these wires, and we introduce a continuum model that explains our observations.
Chiral Crystal Growth under Grinding
Saito, Yukio; Hyuga, Hiroyuki
2008-01-01
To study the establishment of homochirality observed in the crystal growth experiment of chiral molecules from a solution under grinding, we extend the lattice gas model of crystal growth as follows. A lattice site can be occupied by a chiral molecule in R or S form, or can be empty. Molecules form homoclusters by nearest neighbor bonds. They change their chirality if they are isolated monomers in the solution. Grinding is incorporated by cutting and shafling the system randomly. It is shown ...
Chiral squaring and KLT relations
Schreiber, Anders
2016-01-01
We demonstrate that amplitudes based on matter supermultiplets can be combined to provide amplitudes of vector supermultiplets by means of KLT relations. In practice we do this by developing a procedure for removing supersymmetry supercharges from super Yang-Mills theory and supergravity supermultiplets, reducing them to vector and chiral supermultiplets respectively. This way, we reduce the super KLT relations to chiral KLT relations making chiral squaring of amplitudes manifest. We study th...
Chiral dynamics and baryon resonances
Hyodo, Tetsuo
2010-01-01
The structure of baryon resonance in coupled-channel meson-baryon scattering is studied from the viewpoint of chiral dynamics. The meson-baryon scattering amplitude can be successfully described together with the properties of the resonance in the scattering, by implementing the unitarity condition for the amplitude whose low energy structure is constrained by chiral theorem. Recently, there have been a major progress in the study of the structure of the resonance in chiral dynamics. We revie...
Creation of orbital angular momentum states with chiral polaritonic lenses
Dall, Robert; Fraser, Michael D.; Desyatnikov, Anton S.; Li, Guangyao; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Höfling, Sven; Ostrovskaya, Elena A.
2014-01-01
Controlled transfer of orbital angular momentum to exciton-polariton Bose-Einstein condensate spontaneously created under incoherent, off-resonant excitation conditions is a long-standing challenge in the field of microcavity polaritonics. We demonstrate, experimentally and theoretically, a simple and efficient approach to generation of nontrivial orbital angular momentum states by using optically-induced potentials -- chiral polaritonic lenses.
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...
Generalized simplicial chiral models
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...
Generalized simplicial chiral models
Using the auxiliary field representation of the simplicial chiral models on a (d-1)-dimensional simplex, the simplicial chiral models are generalized through replacing the term Tr(AA†) in the Lagrangian of these models by an arbitrary class function of AA†; V(AA†). This is the same method used in defining the generalized two-dimensional Yang-Mills theories (gYM2) from ordinary YM2. We call these models the 'generalized simplicial chiral models'. Using the results of the one-link integral over a U(N) matrix, the large-N saddle-point equations for eigenvalue density function ρ(z) in the weak (β>βc) and strong (βc) regions are computed. In d=2, where the model is in some sense related to the gYM2 theory, the saddle-point equations are solved for ρ(z) in the two regions, and the explicit value of critical point βc is calculated for V(B)=Tr Bn (B=AA†). For V(B)=Tr B2,Tr B3, and TrB4, the critical behaviour of the model at d=2 is studied, and by calculating the internal energy, it is shown that these models have a third order phase transition
Kwiecinska, Joanna I; Cieplak, Marek [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland)
2005-05-11
There are several simple criteria of folding to a native state in model proteins. One of them involves crossing of a threshold value of the root mean square deviation distance away from the native state. Another checks whether all native contacts are established, i.e. whether the interacting amino acids come closer than some characteristic distance. We use Go-like models of proteins and show that such simple criteria may prompt one to declare folding even though fragments of the resulting conformations have a wrong sense of chirality. We propose that a better condition of folding should augment the simple criteria with the requirement that most of the local values of the chirality should be nearly native. The kinetic discrepancy between the simple and compound criteria can be substantially reduced in the Go-like models by providing the Hamiltonian with a term which favours native values of the local chirality. We study the effects of this term as a function of its amplitude and compare it to other models such as ones with side groups and ones with angle-dependent potentials.
Kwiecinska, Joanna I.; Cieplak, Marek
2005-05-01
There are several simple criteria of folding to a native state in model proteins. One of them involves crossing of a threshold value of the root mean square deviation distance away from the native state. Another checks whether all native contacts are established, i.e. whether the interacting amino acids come closer than some characteristic distance. We use Go-like models of proteins and show that such simple criteria may prompt one to declare folding even though fragments of the resulting conformations have a wrong sense of chirality. We propose that a better condition of folding should augment the simple criteria with the requirement that most of the local values of the chirality should be nearly native. The kinetic discrepancy between the simple and compound criteria can be substantially reduced in the Go-like models by providing the Hamiltonian with a term which favours native values of the local chirality. We study the effects of this term as a function of its amplitude and compare it to other models such as ones with side groups and ones with angle-dependent potentials.
Chiral squaring and KLT relations
Schreiber, Anders
2016-01-01
We demonstrate that amplitudes based on matter supermultiplets can be combined to provide amplitudes of vector supermultiplets by means of KLT relations. In practice we do this by developing a procedure for removing supersymmetry supercharges from super Yang-Mills theory and supergravity supermultiplets, reducing them to vector and chiral supermultiplets respectively. This way, we reduce the super KLT relations to chiral KLT relations making chiral squaring of amplitudes manifest. We study these chiral KLT relations, discussing permutation symmetry and vanishing relations. Finally some explicit calculations are done to show how the relations work in detail.
The chiral magnetic effect in hydrodynamical approach
Sadofyev, A. V.; Isachenkov, M. V.
2010-01-01
In quark-gluon plasma nonzero chirality can be induced by the chiral anomaly. When a magnetic field is applied to a system with nonzero chirality an electromagnetic current is induced along the magnetic field. This phenomenon is called the chiral magnetic effect. In this paper appearance of the chiral magnetic effect in hydrodynamical approximation is shown. We consider a hydrodynamical model for chiral liquid with two independent currents of left and right handed particles in the presence of...
Amplification of Chirality through Self-Replication of Micellar Aggregates in Water
Bukhryakov, Konstantin V.
2015-03-17
We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head" and a hydrophobic "tail". Under biphasic conditions, the reaction is autocatalytic, as aggregates facilitate the transfer of hydrophobic molecules to the aqueous phase. When chiral, partially enantioenriched surfactant heads are used, a strong nonlinear induction of chirality in the reaction products is observed. Preseeding the reaction mixture with an amphiphile of one chirality results in the amplification of this product and therefore information transfer between generations of self-replicating aggregates. Because our amphiphiles are capable of catalysis, information transfer, and self-assembly into bounded structures, they present a plausible model for prenucleic acid "lipid world" entities. © 2015 American Chemical Society.
Creation of orbital angular momentum states with chiral polaritonic lenses.
Dall, Robert; Fraser, Michael D; Desyatnikov, Anton S; Li, Guangyao; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Höfling, Sven; Ostrovskaya, Elena A
2014-11-14
Controlled transfer of orbital angular momentum to an exciton-polariton Bose-Einstein condensate spontaneously created under incoherent, off resonant excitation conditions is a long-standing challenge in the field of microcavity polaritonics. We demonstrate, experimentally and theoretically, a simple and efficient approach to the generation of nontrivial orbital angular momentum states by using optically induced potentials-chiral polaritonic lenses. These lenses are produced by a structured optical pump with a spatial distribution of intensity that breaks the chiral symmetry of the system. PMID:25432029
CHIRAL SYMMETRIES IN NUCLEAR PHYSICS
The theoretical concepts of a chirally symmetric meson field theory are reviewed and an overview of the most relevant applications in nuclear physics is given. This includes a unified description of the vacuum properties of hadrons, finite nuclei and hot, dense and strange nuclear matter in an extended chiral SU(3)L/SU(3)R σ-ω model
Two-chiral component microemulsion EKC - chiral surfactant and chiral oil. Part 2: diethyl tartrate.
Kahle, Kimberly A; Foley, Joe P
2007-08-01
In this second study on dual-chirality microemulsions containing a chiral surfactant and a chiral oil, a less hydrophobic and lower interfacial tension chiral oil, diethyl tartrate, is employed (Part 1, Foley, J. P. et al.., Electrophoresis, DOI: 10.1002/elps.200600551). Six stereochemical combinations of dodecoxycarbonylvaline (DDCV: R, S, or racemic, 2.00% w/v), racemic 2-hexanol (1.65% v/v), and diethyl tartrate (D, L, or racemic, 0.88% v/v) were examined as pseudostationary phases (PSPs) for the enantioseparation of six chiral pharmaceutical compounds: pseudoephedrine, ephedrine, N-methyl ephedrine, metoprolol, synephrine, and atenolol. Average efficiencies increased with the addition of a chiral oil to R-DDCV PSP formulations. Modest improvements in resolution and enantioselectivity (alpha(enant)) were achieved with two-chiral-component systems over the one-chiral-component microemulsion. Slight enantioselective synergies were confirmed using a thermodynamic model. Results obtained in this study are compared to those obtained in Part 1 as well as those obtained with chiral MEEKC using an achiral, low-interfacial-tension oil (ethyl acetate). Dual-chirality microemulsions with the more hydrophobic oil dibutyl tartrate yielded, relative to diethyl tartrate, higher efficiencies (100,000-134,000 vs. 80,800-94,300), but lower resolution (1.64-1.91 vs. 2.08-2.21) due to lower enantioselectivities (1.060-1.067 vs. 1.078-1.081). Atenolol enantiomers could not be separated with the dibutyl tartrate-based microemulsions but were partially resolved using diethyl tartrate microemulsions. A comparable single-chirality microemulsion based on the achiral oil ethyl acetate yielded, relative to diethyl tartrate, lower efficiency (78 300 vs. 91 600), higher resolution (1.99 vs. 1.83), and similar enantioselectivities. PMID:17597467
Mass-Selective Chiral Analysis.
Boesl, Ulrich; Kartouzian, Aras
2016-06-12
Three ways of realizing mass-selective chiral analysis are reviewed. The first is based on the formation of diastereomers that are of homo- and hetero- type with respect to the enantiomers of involved chiral molecules. This way is quite well-established with numerous applications. The other two ways are more recent developments, both based on circular dichroism (CD). In one, conventional or nonlinear electronic CD is linked to mass spectrometry (MS) by resonance-enhanced multiphoton ionization. The other is based on CD in the angular distribution of photoelectrons, which is measured in combination with MS via photoion photoelectron coincidence. Among the many important applications of mass-selective chiral analysis, this review focuses on its use as an analytical tool for the development of heterogeneous enantioselective chemical catalysis. There exist other approaches to combine chiral analysis and mass-selective detection, such as chiral chromatography MS, which are not discussed here. PMID:27070181
Mass-Selective Chiral Analysis
Boesl, Ulrich; Kartouzian, Aras
2016-06-01
Three ways of realizing mass-selective chiral analysis are reviewed. The first is based on the formation of diastereomers that are of homo- and hetero- type with respect to the enantiomers of involved chiral molecules. This way is quite well-established with numerous applications. The other two ways are more recent developments, both based on circular dichroism (CD). In one, conventional or nonlinear electronic CD is linked to mass spectrometry (MS) by resonance-enhanced multiphoton ionization. The other is based on CD in the angular distribution of photoelectrons, which is measured in combination with MS via photoion photoelectron coincidence. Among the many important applications of mass-selective chiral analysis, this review focuses on its use as an analytical tool for the development of heterogeneous enantioselective chemical catalysis. There exist other approaches to combine chiral analysis and mass-selective detection, such as chiral chromatography MS, which are not discussed here.
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
Entwicklung neuer chiraler Metathesekatalysatoren
Schlesiger, David Alexander
2012-01-01
Diese Arbeit befasst sich im ersten Teil mit der Synthese chiraler Rutenium-Metathesekatalysatoren. Diese zeichnen sich durch eine Monosubstitution im Rückgrat des N-heterocyclischen Carben-Liganden (NHC-Liganden) aus. Der Katalysator wurde hierbei ausgehend von L-Valin hergestellt. Der Weg verlief über eine Sulfamidat-Zwischenstufe und war bezüglich Ausbeute und Flexibilität dem ursprünglichen Syntheseweg überlegen. Die hoch flexible Route über das Sulfamidat ermöglichte die Herstellung des ...
Microscopic origin of chiral shape induction in achiral crystals
Xiao, Wende; Ernst, Karl-Heinz; Palotas, Krisztian; Zhang, Yuyang; Bruyer, Emilie; Peng, Lingqing; Greber, Thomas; Hofer, Werner A.; Scott, Lawrence T.; Fasel, Roman
2016-04-01
In biomineralization, inorganic materials are formed with remarkable control of the shape and morphology. Chirality, as present in the biomolecular world, is therefore also common for biominerals. Biomacromolecules, like proteins and polysaccharides, are in direct contact with the mineral phase and act as modifiers during nucleation and crystal growth. Owing to their homochirality—they exist only as one of two possible mirror-symmetric isomers—their handedness is often transferred into the macroscopic shape of the biomineral crystals, but the way in which handedness is transmitted into achiral materials is not yet understood at the atomic level. By using the submolecular resolution capability of scanning tunnelling microscopy, supported by photoelectron diffraction and density functional theory, we show how the chiral ‘buckybowl’ hemibuckminsterfullerene arranges copper surface atoms in its vicinity into a chiral morphology. We anticipate that such new insight will find its way into materials synthesis techniques.
Smith, Thomas E.; Richardson, David P.; Truran, George A.; Belecki, Katherine; Onishi, Megumi
2008-01-01
An introduction to the concepts and experimental techniques of diastereoselective synthesis using a chiral auxiliary is described. The 4-benzyl-2-oxazolidinone chiral auxiliary developed by Evans is acylated with propionic anhydride under mild conditions using DMAP as an acyl transfer catalyst. Deprotonation with NaN(TMS)[subscript 2] at -78…
刘克堂; 徐圆圆; 段梦圆; 魏玢莹; 陈倩芸; 程探宇; 刘国华
2013-01-01
Functional graphite oxide materials were synthesized through the Hummers chemical oxidation of graphite. Heterogeneous catalyst was prepared via direct grafting diamine-based chiral ligand to graphite oxide followed by the complexation with organorhodium complex. Such a chiral rhodium catalyst exhibited high catalytic activity and enantioselectivity in asymmetric transfer hydrogenation of aromatic ketones in aqueous medium under mild condition.%以石墨为原料通过Hummer化学氧化法制备出功能化氧化石墨材料,然后将手性二胺基团嫁接到氧化石墨上,再通过后修饰与金属铑配位制备出非均相催化剂,该催化剂在水介质中温和条件下对芳香酮的不对称氢转移反应显示出高的催化活性和对映选择活性.
Wang, Chao; Zong, Lili; Tan, Choon-Hong
2015-08-26
Chiral anion-controlled ion-pairing catalysis was demonstrated to be a wide-ranging strategy that can utilize a variety of cationic metal species. In a similar manner, we envision a complementary strategy using chiral cation in partnership with inorganic anionic metal salts. Herein, we report a chiral dicationic bisguanidinium-catalyzed asymmetric oxidation reaction of alkenes with potassium permanganate. Chiral induction is attributed to ion-pairing interaction between chiral cation and enolate anion. The success of the current permanganate oxidation reaction together with mechanistic insights should provide inspiration for expansion to other anionic metal salts and would open up new paradigms for asymmetric transition metal catalysis, phase-transfer catalysis, and ion-pairing catalysis. PMID:26237178
On Chiral and Nonchiral 1D Supermultiplets
Toppan, Francesco
2011-01-01
In this talk I discuss and clarify some issues concerning chiral and nonchiral 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.
Constructing Self-Dual Chiral Polytopes
Cunningham, Gabe
2011-01-01
An abstract polytope is chiral if its automorphism group has two orbits on the flags, such that adjacent flags belong to distinct orbits. There are still few examples of chiral polytopes, and few constructions that can create chiral polytopes with specified properties. In this paper, we show how to build self-dual chiral polytopes using the mixing construction for polytopes.
Repulsive Casimir Force in Chiral Metamaterials
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.
Repulsive Casimir Force in Chiral Metamaterials
Zhao, R.; Zhou, J.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.
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.
Gupta, R.
1994-12-31
This talk contains an analysis of quenched chiral perturbation theory and its consequences. The chiral behavior of a number of quantities such as the pion mass m{sub pi}{sup 2}, the Bernard-Golterman ratios R and {sub X}, the masses of nucleons, and the kaon B-parameter are examined to see if the singular terms induced by the additional Goldstone boson, {eta}{prime}, are visible in present data. The overall conclusion (different from that presented at the lattice meeting) of this analysis is that even though there are some caveats attached to the indications of the extra terms induced by {eta}{prime} loops, the standard expressions break down when extrapolating the quenched data with m{sub q} < m{sub s}/2 to physical light quarks. I then show that due to the single and double poles in the quenched {eta}{prime}, the axial charge of the proton cannot be calculated using the Adler-Bell-Jackiw anomaly condition. I conclude with a review of the status of the calculation of light quark masses from lattice QCD.
The suggestion by Jaffe that if σ is a light q2q-bar2 state 0++ then even the fundamental chiral transformation properties of the σ becomes unclear, has stimulated much interest. Adler pointed out that in fact the seminal work on chiral symmetry via PCAC consistency, is really quite consistent with the σ being predominantly q2q-bar2. This interpretation was actually backed by subsequent work on effective Lagrangian methods for linear and non linear realizations. More recent work of Achasov suggests that intermediate four-quark states determine amplitudes involving other scalars a0(980) and f0(980) below 1 GeV, and the report by Ning Wu that study on σ meson in J/ψ → ωπ+π- continue to support a non qq-bar σ with mass as low as 390 MeV. It is also noted that more recent re-analysis of πK scattering by S. Ishida et al. together with the work of the E791 Collaboration, support the existence of the scalar κ particle with comparatively light mass as well
Kopp, Victor I.; Zhang, Guoyin; Zhang, Sheng; Genack, Azriel Z.; Neugroschl, Dan
2009-02-01
We propose an in-fiber chiral optical isolator based on chiral fiber polarizer technology and calculate its performance by incorporating the magnetic field into the scattering matrix. The design will be implemented in a special preform, which is passed through a miniature heat zone as it is drawn and twisted. The birefringence of the fiber is controlled by adjusted the diameter of a dual-core optical fiber. By adjusting the twist, the fiber can convert linear to circular polarization and reject one component of circular polarization. In the novel central portion of the isolator, the fiber diameter is large. The effective birefringence of the circular central core with high Verdet constant embedded in an outer core of slightly smaller index of refraction is small. The central potion is a non-reciprocal polarization converter which passes forward traveling left circularly polarized (LCP) light as LCP, while converting backward propagating LCP to right circularly polarized (RCP) light. Both polarizations of light traveling backwards are scattered out of the isolator. Since it is an all-glass structure, we anticipate that the isolator will be able to handle several watts of power and will be environmentally robust.
Chiral perturbation theory with nucleons
I review the constraints posed on the interactions of pions, nucleons and photons by the spontaneously broken chiral symmetry of QCD. The framework to perform these calculations, chiral perturbation theory, is briefly discussed in the meson sector. The method is a simultaneous expansion of the Greens functions in powers of external moments and quark masses around the massless case, the chiral limit. To perform this expansion, use is made of a phenomenological Lagrangian which encodes the Ward-identities and pertinent symmetries of QCD. The concept of chiral power counting is introduced. The main part of the lectures of consists in describing how to include baryons (nucleons) and how the chiral structure is modified by the fact that the nucleon mass in the chiral limit does not vanish. Particular emphasis is put on working out applications to show the strengths and limitations of the methods. Some processes which are discussed are threshold photopion production, low-energy compton scattering off nucleons, πN scattering and the σ-term. The implications of the broken chiral symmetry on the nuclear forces are briefly described. An alternative approach, in which the baryons are treated as very heavy fields, is touched upon
Quarks, baryons and chiral symmetry
Hosaka, Atsushi
2001-01-01
This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail w
Gómez-Rocha, María
2012-01-01
In this article we point out that the unitary transformation that relates the chiral basis $\\{R; I J^{PC}\\}$ and the $\\{I; ^{2S+1}L_J \\}$ basis, which was already derived for canonical spin in instant form, is also applicable in light-cone representations. From the most general expression for the Clebsch-Gordan coefficients of the Poincar\\'e group one can see that the chiral limit brings the angular momentum coupling into a simple form that permits a clear relation in terms of SU(2) Clebsch-Gordan coefficients. It provides a tool of measurement of chiral symmetry in relativistic composite systems.
Chiral Fermions on the Lattice
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.
Field induced spin chirality and chirality switching in magnetic multilayers
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
Chiral Relaxation Time at the Chiral Crossover of Quantum Chromodynamics
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.
胡明明; 李英霞; 白立光
2012-01-01
A novel chiral ruthenium complex RuCl[p-cymene] [ R,R-DPEN] ( R, R-DPEN - 1 ,2-diphe-nylethylenediamine) was synthesized and used as the catalyst for synthesis of chiral a-benzyl ethanol via asymmetric hydrogen transfer reaction of acetophenone. Influence of reaction temperature, reaction time, isopropanol solvent volume, n(acetophenone): n{ RuCl[p-cymene] [ R,R-DPEN] and alkalinity on conversion and ee( enantiomeric excess value) of the asymmetric hydrogen transfer reaction was investigated. The experimental results indicated that the chiral complex exhibited good catalytic activity and favorable enantioselectivity under the following condition:reaction temperature = 40℃, n ( potassium tert-butox-ide):ra(RuCl[p-cymene] [R, R-DPEN]) = 10. 3:1, n ( acetophenone): n( RuCl [p-cymene] [R,R-DPEN] ) = 23. 7: 1 , reaction for 24 h, with conversion of 99. 63% , and ee of 31. 04% .%合成一种新型钌-手性二胺三元配合物RuCl[p-cymene][R,R-DPEN](DPEN=1,2-二苯基乙二胺).利用此配合物作为催化剂催化苯乙酮的不对称氢转移反应,考察反应温度、反应时间、溶剂异丙醇用量、n(苯乙酮)∶n(RuCl[p-cymene][R,R-DPEN])和碱浓度对苯乙酮不对称氢转移反应的转化率和ee值的影响.结果表明,在反应温度40℃、n(叔丁醇钾)∶n(RuCl[p-cymene][R,R-DPEN])=10.3∶1、n(苯乙酮)∶n(RuCl[p-cymene][R,R-DPEN])=23.7∶1和反应时间24h条件下,配合物对苯乙酮不对称氢转移反应具有良好的催化性能和较好的对映选择性,苯乙酮不对称氢转移反应转化率达99.63％,ee值达31.04％.
Chiral allyl silane additions to chiral α-substituted aldehydes
Chiral allyl silane 3 reacted with chiral α-methyl-β-siloxy-aldehydes to afford the corresponding 1,4-syn-products with good diastereo-selectivities independent of the absolute stereochemistry of these aldehydes. The best selectivities are observed when the reactions are carried out by trans metallation of the allyl silane 3 using Tin (IV) Chloride in CH2 CL2 at -78 deg C, before addition of the aldehydes. (author)
Spectral study of a chiral limit without chiral condensate
Bietenholz, Wolfgang; Hip, Ivan
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 distr...
Plasmonic polymers with strong chiroptical response for sensing molecular chirality
Zhai, Dawei; Wang, Peng; Wang, Rong-Yao; Tian, Xiaorui; Ji, Yinglu; Zhao, Wenjing; Wang, Luming; Wei, Hong; Wu, Xiaochun; Zhang, Xiangdong
2015-06-01
We report on the chiroptical transfer and amplification effect observed in plasmonic polymers consisting of achiral gold nanorod monomers linked by cysteine chiral molecules in an end-to-end fashion. A new strategy for controlling the hot spots based circular dichroism (CD)-active sites in plasmonic polymers was developed to realize tailored and reproducible chiroptical activity in a controlled way. We showed that by regulating the bond angles between adjacent nanorods and the degree of polymerization in the linear plasmonic polymer, weak molecular chirality in the ultraviolet spectral region can be amplified by more than two orders of magnitude via the induced CD response in the visible/near infrared region. We demonstrate that this plasmonic polymer can be used to provide not only the Raman ``fingerprint'' information for identifying the molecular identity but also the CD signatures for (i) resolving the enantiomeric pairs of cysteine molecules at a small quantity level, and (ii) quantifying the enantiomeric purity of the chiral analytes. Chiral analyses by chiroptically responsive plasmonic polymers may find important applications in bioscience and biomedicine.We report on the chiroptical transfer and amplification effect observed in plasmonic polymers consisting of achiral gold nanorod monomers linked by cysteine chiral molecules in an end-to-end fashion. A new strategy for controlling the hot spots based circular dichroism (CD)-active sites in plasmonic polymers was developed to realize tailored and reproducible chiroptical activity in a controlled way. We showed that by regulating the bond angles between adjacent nanorods and the degree of polymerization in the linear plasmonic polymer, weak molecular chirality in the ultraviolet spectral region can be amplified by more than two orders of magnitude via the induced CD response in the visible/near infrared region. We demonstrate that this plasmonic polymer can be used to provide not only the Raman ``fingerprint
Life's chirality from prebiotic environments
Gleiser, Marcelo; Walker, Sara Imari
2012-10-01
A key open question in the study of life is the origin of biomolecular homochirality: almost every life-form on Earth has exclusively levorotary amino acids and dextrorotary sugars. Will the same handedness be preferred if life is found elsewhere? We review some of the pertinent literature and discuss recent results suggesting that life's homochirality resulted from sequential chiral symmetry breaking triggered by environmental events. In one scenario, autocatalytic prebiotic reactions undergo stochastic fluctuations due to environmental disturbances, in a mechanism reminiscent of evolutionary punctuated equilibrium: short-lived destructive events may lead to long-term enantiomeric excess. In another, chiral-selective polymerization reaction rates influenced by environmental effects lead to substantial chiral excess even in the absence of autocatalysis. Applying these arguments to other potentially life-bearing platforms has implications to the search for extraterrestrial life: we predict that a statistically representative sampling of extraterrestrial stereochemistry will be racemic (chirally neutral) on average.
Review of chiral perturbation theory
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.
Mickelsson, J
1996-01-01
A calculation of the chiral anomaly on a finite lattice without fermion doubling is presented . The lattice gauge field is defined in the spirit of noncommutative geometry. Standard formulas for the continuum anomaly are obtained as a limit.
Chirality dependence of the absorption cross-section of carbon nanotubes.
Vialla, Fabien; Roquelet, Cyrielle; Langlois, Benjamin; Delport, Géraud; Santos, Sylvia,; Deleporte, Emmanuelle; Roussignol, Philippe; Delalande, Claude; Voisin, Christophe; Lauret, Jean-Sébastien
2013-01-01
The variation of the optical absorption of carbon nanotubes with their geometry has been a long standing question at the heart of both metrological and applicative issues, in particular because optical spectroscopy is one of the primary tools for the assessment of the chiral species abundance of samples. Here, we tackle the chirality dependence of the optical absorption with an original method involving ultra-efficient energy transfer in porphyrin/nanotube compounds that allows uniform photo-...
Chiral thermodynamics of nuclear matter
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.
Chiral thermodynamics of nuclear matter
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.
Chiral symmetry and lattice fermions
Creutz, Michael
2013-01-01
Lattice gauge theory and chiral perturbation theory are among the primary tools for understanding non-perturbative aspects of QCD. I review several subtle and sometimes controversial issues that arise when combining these techniques. Among these are one failure of partially quenched chiral perturbation theory when the valence quarks become lighter than the average sea quark mass and a potential ambiguity in comparisons of perturbative and lattice properties of non-degenerate quarks.
Restoration of Chiral Symmetry in Excited Hadrons
Physics of the low-lying and high-lying hadrons in the light flavor sector is reviewed. While the low-lying hadrons are strongly affected by the spontaneous breaking of chiral symmetry, in the high-lying hadrons the chiral symmetry is restored. A manifestation of the chiral symmetry restoration in excited hadrons is a persistence of the chiral multiplet structure in both baryon and meson spectra. Meson and baryon chiral multiplets are classified. A relation between the chiral symmetry restoration and the string picture of excited hadrons is discussed. (author)
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.
Chiral symmetry in rotating systems
Malik, Sham S.
2015-08-01
The triaxial rotating system at critical angular momentum I ≥Iband exhibits two enatiomeric (the left- and right-handed) forms. These enatiomers are related to each other through dynamical chiral symmetry. The chiral symmetry in rotating system is defined by an operator χ ˆ =Rˆy (π) T ˆ, which involves the product of two distinct symmetries, namely, continuous and discrete. Therefore, new guidelines are required for testing its commutation with the system Hamiltonian. One of the primary objectives of this study is to lay down these guidelines. Further, the possible impact of chiral symmetry on the geometrical arrangement of angular momentum vectors and investigation of observables unique to nuclear chiral-twins is carried out. In our model, the angular momentum components (J1, J2, J3) occupy three mutually perpendicular axes of triaxial shape and represent a non-planar configuration. At certain threshold energy, the equation of motion in angular momentum develops a second order phase transition and as a result two distinct frames (i.e., the left- and right-handed) are formed. These left- and right-handed states correspond to a double well system and are related to each other through chiral operator. At this critical angular momentum, the centrifugal and Coriolis interactions lower the barrier in the double well system. The tunneling through the double well starts, which subsequently lifts the degeneracy among the rotational states. A detailed analysis of the behavior of rotational energies, spin-staggering, and the electromagnetic transition probabilities of the resulting twin-rotational bands is presented. The ensuing model results exhibit similarities with many observed features of the chiral-twins. An advantage of our formalism is that it is quite simple and it allows us to pinpoint the understanding of physical phenomenon which lead to chiral-twins in rotating systems.
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.
Rahaman, Anisur
2015-01-01
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 \\cite{THAR}. The model was studied there with a Faddeevian class of regularization that contained few ambiguity parameters 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 remain exactly solvable but also does not loose the unitarity like the chiral generation of the Schwinger model. The phase space structure and the theoretical spectrum of this new model has been determined in the present scenario through Dirac's method of quantization of constraint system. The theoretical spectrum is found to ...
Water-soluble chiral metallopeptoids.
Baskin, Maria; Maayan, Galia
2015-09-01
Metal ions play a significant role in the activity of biological systems including catalysis, recognition and folding. Therefore, introducing metal ions into peptidomimetic oligomers is a potential way for creating biomimetic metal complexes toward applications in sensing, recognition, drug design and catalysis. Herein we report the design, synthesis and characterization of water-soluble chiral N-substituted glycine oligomers, "peptoids," with one and two distinct intramolecular binding sites for metal ions such as copper and cobalt. We demonstrate for the first time the incorporation of the chiral hydrophilic group (S)-(+)-1-methoxy-2-propylamine (Nsmp) within peptoid sequences, which provides both chirality and water solubility. Two peptoids, a heptamer, and a dodecamer bearing two and four 8-hydroxyquinoline (HQ) groups respectively as metal-binding ligands, were synthesized on solid support using the submonomer approach. Using UV-titrations and ESI-MS analysis we demonstrate the creation of a novel metallopeptoid bearing two metal ions in distinct binding sites via intramolecular chelation. Exciton couplet circular dichroism (ECCD) demonstrated chiral induction from the chiral non-helical peptoids to the metal centers. PMID:25969151
Nucleon form factors. Probing the chiral limit
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated on the lattice. However, reliability of the results is limited by systematic errors due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet unaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with Nf=2, non-perturbatively O(a)-improved Wilson fermions at very small quark masses down to 340 MeV pion mass, where we start to probe the relevant quark mass region. (orig.)
Nucleon form factors. Probing the chiral limit
Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Dept.; Horsley, R. [Edinburgh Univ. (GB). School of Physics] (and others)
2006-10-15
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated on the lattice. However, reliability of the results is limited by systematic errors due to the required extrapolation to physical quark masses. Chiral effective field theories predict a rather strong quark mass dependence in a range which was yet unaccessible for lattice simulations. We give an update on recent results from the QCDSF collaboration using gauge configurations with Nf=2, non-perturbatively O(a)-improved Wilson fermions at very small quark masses down to 340 MeV pion mass, where we start to probe the relevant quark mass region. (orig.)
Repulsive Casimir force in chiral metamaterials.
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. PMID:19792309
Chiral gap effect in curved space
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.
Chiral measurements with the Fixed-Point Dirac operator and construction of chiral currents
In this preliminary study, we examine the chiral properties of the parametrized Fixed-Point Dirac operator DFP, see how to improve its chirality via the Overlap construction, measure the renormalized quark condensate Σ-circumflex and the topological susceptibility χt, and investigate local chirality of near zero modes of the Dirac operator. We also give a general construction of chiral currents and densities for chiral lattice actions
Shear Viscosity of Turbulent Chiral Plasma
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.
Lattice QCD with dynamical chirally improved quarks
Full text: We simulate lattice QCD with two flavors of chirally improved dynamical (sea) quarks. The chirally improved lattice action allows to address some of the questions concerning chiral symmetry in lattice QCD.We discuss the status and prospects of our simulations as well as recent results. (author)
Quenched Chiral Perturbation Theory to one loop
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
Neutrino Oscillation Induced by Chiral Phase Transition
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.
Nonequilibrium Chiral Dynamics and Effective Lagrangians
Nicola, A G
2001-01-01
We review our recent work on Chiral Lagrangians out of thermal equilibrium, which are introduced to analyse the pion gas formed after a Relativistic Heavy Ion Collision. Chiral Perturbation Theory is extended by letting $\\fpi$ be time dependent and allows to describe explosive production of pions in parametric resonance. This mechanism could be relevant if hadronization occurs at the chiral phase transition.
Solutions of ward's modified chiral model
We discuss the adaptation of Uhlenbeck's method of solving the chiral model in 2 Euclidean dimensions to Ward's modified chiral model in (2+1) dimensions. We show that the method reduces the problem of solving the second-order partial differential equations for the chiral field to solving a sequence of first-order partial differential equations for time dependent projector valued fields
Dynamical evolution of the chiral magnetic effect: applications to the quark-gluon plasma
Manuel, Cristina
2015-01-01
We study the dynamical evolution of the so-called chiral magnetic effect in an electromagnetic conductor. To this end, we consider the coupled set of corresponding Maxwell and chiral anomaly equations, and we prove that these can be derived from chiral kinetic theory. After integrating the chiral anomaly equation over space in a closed volume, it leads to a quantum conservation law of the total helicity of the system. A change in the magnetic helicity density comes together with a modification of the chiral fermion density. We study in Fourier space the coupled set of anomalous equations and we obtain the dynamical evolution of the magnetic fields, magnetic helicity density, and chiral fermion imbalance. Depending on the initial conditions we observe how the helicity might be transferred from the fermions to the magnetic fields, or vice versa, and find that the rate of this transfer also depends on the scale of wavelengths of the gauge fields in consideration. We then focus our attention on the quark-gluon pl...
Fidler, Andrew F.; Singh, Ved P.; Long, Phillip D.; Dahlberg, Peter D.; Engel, Gregory S.
2014-02-01
Time-resolved ultrafast optical probes of chiral dynamics provide a new window allowing us to explore how interactions with such structured environments drive electronic dynamics. Incorporating optical activity into time-resolved spectroscopies has proven challenging because of the small signal and large achiral background. Here we demonstrate that two-dimensional electronic spectroscopy can be adapted to detect chiral signals and that these signals reveal how excitations delocalize and contract following excitation. We dynamically probe the evolution of chiral electronic structure in the light-harvesting complex 2 of purple bacteria following photoexcitation by creating a chiral two-dimensional mapping. The dynamics of the chiral two-dimensional signal directly reports on changes in the degree of delocalization of the excitonic states following photoexcitation. The mechanism of energy transfer in this system may enhance transfer probability because of the coherent coupling among chromophores while suppressing fluorescence that arises from populating delocalized states. This generally applicable spectroscopy will provide an incisive tool to probe ultrafast transient molecular fluctuations that are obscured in non-chiral experiments.
Chiral interaction and biomolecular evolution
Recent developments in the concept of chiral interaction open now new options and dynamical possibilities for biomolecules which have so far been overlooked. A few of these possibilities are mentioned, such as the control mechanism of enzymatic activity and the role played by non-ergodicity in evolutionary processes. It is shown that chiral interaction, being a surface phenomenon, does not obey Barron's symmetry constraints, which are suitable for force fields present in bulk interactions. In particular, the situation at the ocean-air surface in the prebiotic era is described, as well as the possible role played by chiral interaction in conjunction with the terrestrial magnetic field normal to the ocean surface, which could have lead to a process of deracernization at the ocean-air interface. (author)
Nucleus as a chiral filter: the role of the Δ(1232)
We describe how two different modes of chiral symmetry can be seen in nuclei. In particular, it is shown that the nuclear axial charge or more precisely the O+O-, ΔT=1 transition at zero momentum transfer probe the nuclear configuration wherein the axial charge gsub(A) is effectively enhanced in nuclear medium due to soft pions, symptomatic of the Goldstone realization of chiral symmetry in the medium while the Gamow-Teller resonances probe the configuration wherein soft pions are no longer operative, suggesting an approach toward the Wigner realization of chiral symmetry. Using the celebrated Adler-Weisberger relation, it is argued that the observed approximately 50% quenching of the Gamow-Teller strength reflects the possibility that the Gamow-Teller operator sees the quarks inside the bag, blind to the Goldstone vacuum outside. Some implications on chiral phase transitions are also discussed
Chiral symmetry on the lattice
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model
Chiral Baryon with Quantized Pions
McNeil, J A
1993-01-01
We study a hybrid chiral model for the nucleon based on the linear sigma model with explicit quarks. We solve the model using a Fock-space configuration consisting of three quarks plus three quarks and a pion as the ground state ansatz in place of the ``hedgehog'' ansatz. We minimize the expectation value of the chiral hamiltonian in this ground state configuration and solve the resulting equations for nucleon quantum numbers. We calculate the canonical set of nucleon observables and compare with previous work.
Collisions in Chiral Kinetic Theory.
Chen, Jing-Yuan; Son, Dam T; Stephanov, Mikhail A
2015-07-10
Using a covariant formalism, we construct a chiral kinetic theory Lorentz invariant to order O(ℏ), 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 the chiral vortical effect. PMID:26207458
Collisions in Chiral Kinetic Theory
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.
Holographic Chiral Electric Separation Effect
Pu, Shi; Wu, Shang-Yu; Yang, Di-Lun
2014-01-01
We investigate the chiral electric separation effect, where an axial current is induced by an electric field in the presence of both vector and axial chemical potentials, in a strongly coupled plasma via the Sakai-Sugimoto model with an $U(1)_R\\times U(1)_L$ symmetry. By introducing different chemical potentials in $U(1)_R$ and $U(1)_L$ sectors, we compute the axial direct current (DC) conductivity stemming from the chiral current and the normal DC conductivity. We find that the axial conduct...
Chiral symmetry on the lattice
Creutz, M.
1994-11-01
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model.
Mechanical chirality: A chiral catalyst with a ring to it
Goldup, Stephen M.
2016-05-01
A chiral [2]rotaxane in which the asymmetry is derived from the way in which the two components are mechanically interlocked -- rather than being encoded in the covalent connectivity of the components themselves -- has been shown to act as an enantioselective organocatalyst.
Scaling laws in chiral hydrodynamic turbulence
Yamamoto, Naoki
2016-01-01
We study the turbulent regime of chiral (magneto)hydrodynamics for charged and neutral matter with chirality imbalance. We find that the chiral magnetohydrodynamics for charged plasmas possesses a unique scaling symmetry only without fluid helicity under the local charge neutrality. We also find a different type of unique scaling symmetry in the chiral hydrodynamics for neutral matter with fluid helicity in the inertial range. We show that these symmetries dictate the self-similar inverse cascade of the magnetic and kinetic energies. Our results imply the possible inverse energy cascade in core-collapse supernovae due to the chiral transport of neutrinos.
Chiral magnetic effect in the PNJL model
Fukushima, Kenji; Gatto, Raoul
2010-01-01
We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop (PNJL model) in the presence of a strong magnetic field and a chiral chemical potential $\\mu_5$ which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. Firstly we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of $\\mu_5$ on the phase structure. Finally the chirality charge, electric current, and their susceptibility, which are relevant to the Chiral Magnetic Effect, are computed in the model.
K stability and stability of chiral ring
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.
Scaling laws in chiral hydrodynamic turbulence
Yamamoto, Naoki
2016-06-01
We study the turbulent regime of chiral (magneto)hydrodynamics for charged and neutral matter with chirality imbalance. We find that the chiral magnetohydrodynamics for charged plasmas possesses a unique scaling symmetry, only without fluid helicity under the local charge neutrality. We also find a different type of unique scaling symmetry in the chiral hydrodynamics for neutral matter with fluid helicity in the inertial range. We show that these symmetries dictate the self-similar inverse cascade of the magnetic and kinetic energies. Our results imply the possible inverse energy cascade in core-collapse supernovae due to the chiral transport of neutrinos.
Thermal chiral vortical and magnetic waves: new excitation modes in chiral fluids
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.
Casimir-Polder Forces between Chiral Objects
Butcher, David T; Scheel, Stefan
2012-01-01
The chiral component of the Casimir-Polder potential is derived within the framework of macroscopic quantum electrodynamics. It is shown to exist only if the particle and the medium are both chiral. Furthermore, the chiral component of the Casimir-Polder potential can be attractive or repulsive, depending on the chirality of the molecule and the medium. The theory is applied to a cavity geometry in the non-retarded limit with the intention of enantiomer separation. For a ground state molecule the chiral component is dominated by the electric component and thus no explicit separation will happen. If the molecule is initially in an excited state the electric component of the Casimir-Polder force can be suppressed by an appropriate choice of material and the chiral component can select the molecule based on its chirality, allowing enantiomeric separation to occur.
Casimir–Polder forces between chiral objects
The chiral component of the Casimir–Polder potential is derived within the framework of macroscopic quantum electrodynamics. It is shown to exist only if the particle and the medium are both chiral. Furthermore, the chiral component of the Casimir–Polder potential can be attractive or repulsive, depending on the chirality of the molecule and the medium. The theory is applied to a cavity geometry in the non-retarded limit with the intention of enantiomer separation. For a ground state molecule the chiral component is dominated by the electric component and thus no explicit separation will happen. If the molecule is initially in an excited state the electric component of the Casimir–Polder force can be suppressed by an appropriate choice of material and the chiral component can select the molecule based on its chirality, allowing enantiomeric separation to occur. (paper)
Chiral Cosmological Models: Dark Sector Fields Description
Chervon, S V
2014-01-01
The present review is devoted to a Chiral Cosmological Model as the self-gravitating nonlinear sigma model with the potential of (self)interactions employed in cosmology. The chiral cosmological model has successive applications in descriptions of the inflationary epoch of the Universe evolution; the present accelerated expansion of the Universe also can be described by the chiral fields multiplet as the dark energy in wide sense. To be more illustrative we are often addressed to the two-component chiral cosmological model. Namely, the two-component chiral cosmological model describing the phantom field with interaction to a canonical scalar field is analyzed in details. New generalized model of quintom character is proposed and exact solutions are founded out. In the review we represented the perturbation theory for chiral cosmological model with the aim to describe the structure formation using the progress achieved in the inflation theory. It was shown that cosmological perturbations from chiral fields can...
Chirality effect in disordered graphene ribbon junctions
We investigate the influence of edge chirality on the electronic transport in clean or disordered graphene ribbon junctions. By using the tight-binding model and the Landauer-Büttiker formalism, the junction conductance is obtained. In the clean sample, the zero-magnetic-field junction conductance is strongly chirality-dependent in both unipolar and bipolar ribbons, whereas the high-magnetic-field conductance is either chirality-independent in the unipolar or chirality-dependent in the bipolar ribbon. Furthermore, we study the disordered sample in the presence of magnetic field and find that the junction conductance is always chirality-insensitive for both unipolar and bipolar ribbons with adequate disorders. In addition, the disorder-induced conductance plateaus can exist in all chiral bipolar ribbons provided the disorder strength is moderate. These results suggest that we can neglect the effect of edge chirality in fabricating electronic devices based on the magnetotransport in a disordered graphene ribbon. (paper)
The chiral symplectic universality class
Asada, Yoichi; Slevin, Keith; Ohtsuki, Tomi
2003-01-01
We report a numerical investigation of localization in the SU(2) model without diagonal disorder. At the band center, chiral symmetry plays an important role. Our results indicate that states at the band center are critical. States away from the band center but not too close to the edge of the spectrum are metallic as expected for Hamiltonians with symplectic symmetry.
Chiral symmetry in perturbative QCD
The chiral symmetry of quantum chromodynamics with massless quarks is unbroken in perturbation theory. Dimensional regularization is used. The ratio of the vector and axial vector renormalization constante is shown to be independent of the renormalization mass. The general results are explicitly verified to fourth order in g, the QCD coupling constant
Dynamics of the chiral transition
Measurements of disoriented chiral condensates (DCC) in heavy ion collisions at RHIC can yield fundamental information on the nature of the QCD phase transition. I review theoretical efforts to understand DCC formation and present work in progress on possible experimental ramifications
Instantons and chiral symmetry breaking
A detailed investigation of chiral symmetry breaking due to instanton dynamics is carried out, within the framework of the dilute gas approximation, for quarks in both the fundamental and adjoint representations of SU(2). The momentum dependence of the dynamical mass is found to be very similar in each representation. (orig.)
Algebraic study of chiral anomalies
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’.
Asymmetric Synthesis via Chiral Aziridines
Tanner, David Ackland; Harden, Adrian; Wyatt, Paul; Andersson, Pher G.; Johansson, Fredrik
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...
Diller, Carolina; Fenster, Charles B
2016-07-01
Corolla chirality, the pinwheel arrangement of petals within a flower, is found throughout the core eudicots. In 15 families, different chiral type flowers (i.e., right or left rotated corolla) exist on the same plant, and this condition is referred to as unfixed/enantiomorphic corolla chirality. There are no investigations on the significance of unfixed floral chirality on directed pollen movement even though analogous mirror image floral designs, for example, enantiostyly, has evolved in response to selection to direct pollinator and pollen movement. Here, we examine the role of corolla chirality on directing pollen transfer, pollinator behavior, and its potential influence on disassortative mating. We quantified pollen transfer and pollinator behavior and movement for both right and left rotated flowers in two populations of Hypericum perforatum. In addition, we quantified the number of right and left rotated flowers at the individual level. Pollinators were indifferent to corolla chirality resulting in no difference in pollen deposition between right and left flowers. Corolla chirality had no effect on pollinator and pollen movement between and within chiral morphs. Unlike other mirror image floral designs, corolla chirality appears to play no role in promoting disassortative mating in this species. PMID:27547334
Stereochemical Communication within a Chiral Ion Pair Catalyst.
Merten, Christian; Pollok, Corina H; Liao, Saihu; List, Benjamin
2015-07-20
Ionic interactions are increasingly appreciated as a key, asymmetry-inducing factor in enantioselective catalytic transformations, including those involving Brønsted acid or base catalysis, phase-transfer catalysis, and related processes. However, a detailed understanding of these interactions is often lacking. Herein, we show how an enantiopure anion enforces a chiral conformation onto a catalytically relevant achiral cation. Specifically, we use vibrational circular dichroism (VCD) spectroscopy to monitor the transmission of stereochemical information from a chiral phosphate anion to a flexible manganese(III)-salen cation. We show that VCD can be used to study solvent effects and that the obtained chiroptical data directly and quantitatively correlate with the experimentally observed enantioselectivity in an asymmetric olefin epoxidation reaction. PMID:26101152
Chiral Lagrangian and chiral quark model from confinement in QCD
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.
Spectral study of a chiral limit without chiral condensate
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...
Chiral logarithms in quenched QCD
The quenched chiral logarithms are examined on a 163x28 lattice with Iwasaki gauge action and overlap fermions. The pion decay constant fpi is used to set the lattice spacing, a = 0.200(3) fm. With pion mass as low as ∼180 MeV, we see the quenched chiral logarithms clearly in mpi2/m and fP, the pseudoscalar decay constant. The authors analyze the data to determine how low the pion mass needs to be in order for the quenched one-loop chiral perturbation theory (chiPT) to apply. With the constrained curve-fitting method, they are able to extract the quenched chiral logarithmic parameter delta together with other low-energy parameters. Only for mpi<=300 MeV do we obtain a consistent and stable fit with a constant delta which they determine to be 0.24(3)(4) (at the chiral scale Lambdachi = 0.8 GeV). By comparing to the 123x28 lattice, they estimate the finite volume effect to be about 2.7% for the smallest pion mass. They also fitted the pion mass to the form for the re-summed cactus diagrams and found that its applicable region is extended farther than the range for the one-loop formula, perhaps up to mpi ∼500-600 MeV. The scale independent delta is determined to be 0.20(3) in this case. The authors study the quenched non-analytic terms in the nucleon mass and find that the coefficient C1/2 in the nucleon mass is consistent with the prediction of one-loop chiPT. They also obtain the low energy constant L5 from fpi. They conclude from this study that it is imperative to cover only the range of data with the pion mass less than ∼300 MeV in order to examine the chiral behavior of the hadron masses and decay constants in quenched QCD and match them with quenched one-loop chiPT
Chiral Negative-Index Metamaterials in Terahertz
Zhang, Shuang; Li, Jensen; Lu, Xinchao; Zhang, Weili; Zhang, Xiang
2008-01-01
Negative index metamaterials (NIMs) give rise to unusual and intriguing properties and phenomena, which may lead to important applications such as superlens, subwavelength cavity and slow light devices. However, the negative refractive index in metamaterials normally requires a stringent condition of simultaneously negative permittivity and negative permeability. A new class of negative index metamaterials - chiral NIMs, have been recently proposed. In contrast to the conventional NIMs, chiral NIMs do not require the above condition, thus presenting a very robust route toward negative refraction. Here we present the first experimental demonstration of a chiral metamaterial exhibiting negative refractive index down to n=-5 at terahertz frequencies, with only a single chiral resonance. The strong chirality present in the structure lifts the degeneracy for the two circularly polarized waves and relieves the double negativity requirement. Chiral NIM are predicted to possess intriguing electromagnetic properties t...
Stable Pentaquarks from Strange Chiral Multiplets
Silas Beane
2004-12-01
The assumption of strong diquark correlations in the QCD spectrum suggests flavor multiplets of hadrons that are degenerate in the chiral limit. Generally it would be unnatural for there to be degeneracy in the hadron spectrum that is not protected by a QCD symmetry. Here we show--for pentaquarks constructed from diquarks--that these degeneracies can be naturally protected by the full chiral symmetry of QCD. The resulting chiral multiplet structure recovers the ideally-mixed pentaquark mass spectrum of the diquark model, and interestingly, requires that the axial couplings of the pentaquarks to states outside the degenerate multiplets vanish in the chiral limit. This result suggests that if these hadrons exist, they are stable in the chiral limit and therefore have widths that scale as the fourth power of the kaon mass over the chiral symmetry breaking scale. Natural-size widths are of order a few MeV.
Anomalous Maxwell equations for inhomogeneous chiral plasma
Gorbar, E V; Vilchinskii, S; Rudenok, I; Boyarsky, A; Ruchayskiy, O
2016-01-01
Using the chiral kinetic theory we derive the electric and chiral current densities in inhomogeneous relativistic plasma. We also derive equations for the electric and chiral charge chemical potentials that close the Maxwell equations in such a plasma. The analysis is done in the regimes with and without a drift of the plasma as a whole. In addition to the currents present in the homogeneous plasma (Hall current, chiral magnetic, chiral separation, and chiral electric separation effects, as well as Ohm's current) we derive several new terms associated with inhomogeneities of the plasma. Apart from various diffusion-like terms, we find also new dissipation-less terms that are independent of relaxation time. Their origin can be traced to the Berry curvature modifications of the kinetic theory.
Chiral Symmetry Restoration from a Boundary
Tiburzi, B C
2013-01-01
The boundary of a manifold can alter the phase of a theory in the bulk. We explore the possibility of a boundary-induced phase transition for the chiral symmetry of QCD. In particular, we investigate the consequences of imposing homogeneous Dirichlet boundary conditions on the quark fields. Such boundary conditions are employed on occasion in lattice gauge theory computations, for example, when including external electromagnetic fields, or when computing quark propagators with a reduced temporal extent. Homogeneous Dirichlet boundary conditions force the chiral condensate to vanish at the boundary, and thereby obstruct the spontaneous breaking of chiral symmetry in the bulk. As the restoration of chiral symmetry due to a boundary is a non-perturbative phenomenon, we utilize the sigma model to exemplify the issues. Using this model, we find that chiral symmetry is completely restored if the length of the compact direction is less than 2.0 fm. For lengths greater than about 4 fm, an approximately uniform chiral...
Asymmetric synthesis using chiral-encoded metal.
Yutthalekha, Thittaya; Wattanakit, Chularat; Lapeyre, Veronique; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander
2016-01-01
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. PMID:27562028
Phases of chiral gauge theories
We discuss the behavior of two non-supersymmetric chiral SU(N) gauge theories, involving fermions in the symmetric and antisymmetric two-index tensor representations respectively. In addition to global anomaly matching, we employ a recently proposed inequality constraint on the number of effective low energy (massless) degrees of freedom of a theory, based on the thermodynamic free energy. Several possible zero temperature phases are consistent with the constraints. A simple picture for the phase structure emerges if these theories choose the phase, consistent with global anomaly matching, that minimizes the massless degree of freedom count defined through the free energy. This idea suggests that confinement with the preservation of the global symmetries through the formation of massless composite fermions is in general not preferred. While our discussion is restricted mainly to bilinear condensate formation, higher dimensional condensates are considered for one case. We conclude by commenting briefly on two related supersymmetric chiral theories. (c) 2000 The American Physical Society
Bootstrapping N=2 chiral correlators
Lemos, Madalena; Liendo, Pedro
2016-01-01
We apply the numerical bootstrap program to chiral operators in four-dimensional 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 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.
Bootstrapping N=2 chiral correlators
Lemos, Madalena [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Liendo, Pedro [Humboldt-Univ. Berlin (Germany). IMIP
2015-12-15
We apply the numerical bootstrap program to chiral operators in four-dimensional 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 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.
Homogenization of resonant chiral metamaterials
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 a...... critical density exists above which increasing coupling between neighboring meta-atoms prevails a reasonable homogenization. On the contrary, a dilution in excess will induce features reminiscent to photonic crystals likewise prevailing a homogenization. Based on Bloch mode dispersion we introduce 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....
Bootstrapping N=2 chiral correlators
We apply the numerical bootstrap program to chiral operators in four-dimensional 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 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.
Dimonte, Alice; Adamatzky, Andrew; Erokhin, Victor; Levin, Michael
2016-02-01
Left-right patterning and lateralised behaviour is an ubiquitous aspect of plants and animals. The mechanisms linking cellular chirality to the large-scale asymmetry of multicellular structures are incompletely understood, and it has been suggested that the chirality of living cells is hardwired in their cytoskeleton. We examined the question of biased asymmetry in a unique organism: the slime mould Physarum polycephalum, which is unicellular yet possesses macroscopic, complex structure and behaviour. In laboratory experiment using a T-shape, we found that Physarum turns right in more than 74% of trials. The results are in agreement with previously published studies on asymmetric movement of muscle cells, neutrophils, liver cells and growing neural filaments, and for the first time reveal the presence of consistently-biased laterality in the fungi kingdom. Exact mechanisms of the slime mould's direction preference remain unknown. PMID:26747637
An epistemological note on chirality
The terms ''chiral'' and ''achiral'' are sharply defined when applied to geometric figures or models. The same terms are also commonly used to refer to the real systems to which these models have been adjoined. e.g., molecules, solvents, or reagents. Here, the terms are not sharply defined but depend upon conditions or measurement. The contrast between the geometric and operational usages is discussed in detail
Chiral Primaries in Strange Metals
Isachenkov, Mikhail(DESY Hamburg, Theory Group, Notkestrasse 85, D-22607 Hamburg, Germany); Kirsch, Ingo; Schomerus, Volker
2014-01-01
It was suggested recently that the study of 1-dimensional QCD with fermions in the adjoint representation could lead to an interesting toy model for strange metals and their holographic formulation. In the high density regime, the infrared physics of this theory is described by a constrained free fermion theory with an emergent N=(2,2) superconformal symmetry. In order to narrow the choice of potential holographic duals, we initiate a systematic search for chiral primaries in this model. We a...
Chiral Lagrangians and the SSC
In the event that the SSC does not observe any resonances such as a Higgs boson or a techni-rho meson, we would like to know if the SSC can still discover something about the nature of the electroweak symmetry breaking. We will use chiral Lagrangian techniques to address this question and analyze their utility for studying events containing W and Z gauge bosons at the SSC. 20 refs., 4 figs
Chiral symmetry and nucleon structure
Holstein, B.R. (Massachusetts Univ., Amherst, MA (United States). Dept. of Physics and Astromony Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory)
1992-01-01
Recently it has been realized that significant tests of the validity of QCD are available in low energy experiments (E < 500 MeV) by exploiting the property of (broken) chiral symmetry. This technique has been highly developed in The Goldstone boson sector by the work of Gasser and Leutwyler. Application to the nucleon system is much more difficult and is now being carefully developed.
Chiral solitons a review volume
1987-01-01
This review volume on topological and nontopological chiral solitons presents a global view on the current developments of this field in particle and nuclear physics. The book addresses problems in quantization, restoration of translational and rotational symmetry, and the field theoretical approach to solitons which are common problems in the field of solitons. Primarily aimed for graduate students and the novice in the field, the collected articless cover a broad spectrum of topics in formalism as well as phenomenology.
Majorana Neutrino: Chirality and Helicity
Dvoeglazov, Valeriy V
2012-01-01
We introduce the Majorana spinors in the momentum representation. They obey the Dirac-like equation with eight components, which has been first introduced by Markov. Thus, the Fock space for corresponding quantum fields is doubled (as shown by Ziino). Particular attention has been paid to the questions of chirality and helicity (two concepts which frequently are confused in the literature) for Dirac and Majorana states.
Staggered chiral random matrix theory
We present a random matrix theory for the staggered lattice QCD Dirac operator. The staggered random matrix theory 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.
Chiral Particle Separation by a Nonchiral Microlattice
Bogunovic, Lukas; Fliedner, Marc; Eichhorn, Ralf; Wegener, Sonja; Regtmeier, Jan; Anselmetti, Dario; Reimann, Peter
2012-09-01
We conceived a model experiment for a continuous separation strategy of chiral molecules (enantiomers) without the need of any chiral selector structure or derivatization agents: Microparticles that only differ by their chirality are shown to migrate along different directions when driven by a steady fluid flow through a square lattice of cylindrical posts. In accordance with our numerical predictions, the transport directions of the enantiomers depend very sensitively on the orientation of the lattice relative to the fluid flow.
Enantiomeric Separations using Chiral Counter-Ions
Haglöf, Jakob
2010-01-01
This thesis describes the use of chiral counter-ions for the enantiomeric separation of amines in non-aqueous capillary electrophoresis. The investigations have been concentrated on studies of the influence, of the chiral counter-ion, the solvent, the electrolyte and the analyte, on the enantioselective separation. Modified divalent dipeptides have been introduced in capillary electrophoresis for the separation of amino alcohols and chiral resolution of amines. Association constants for the i...
Chiral Seismic Attenuation with Acoustic Metamaterials
Hector Torres-Silva; Diego Torres Cabezas
2013-01-01
We study the analogy between the linear elasticity theory equations and classical Maxwell equation with chiral effects and we propose a new method of an earthquake-resistant design to support conventional aseismic designs using acoustic metamaterials. We suggest a simple and practical method to reduce the amplitude of a seismic wave exponentially. Our device is like an attenuator of a chiral seismic wave. Constructing a cylindrical shell-type waveguide that creates a stop-band for the chiral...
Chiral magnetic effect by synthetic gauge fields
Hayata, Tomoya
2016-01-01
We study the dynamical generation of the chiral chemical potential in a Weyl metal constructed from a three-dimensional optical lattice and subject to synthetic gauge fields. By numerically solving the Boltzmann equation with the Berry curvature in the presence of parallel synthetic electric and magnetic fields, we find that the spectral flow and the ensuing chiral magnetic current emerge. We show that the spectral flow and the chiral chemical potential can be probed by time-of-flight imaging.
Random Matrix Theory and Chiral Logarithms
Berbenni-Bitsch, M. E.; Göckeler, M.; Hehl, H.; Meyer, S.; Rakow, P. E. L.; Schäfer, A.; Wettig, T.
1999-01-01
Abstract: Recently, the contributions of chiral logarithms predicted by quenched chiral perturbation theory have been extracted from lattice calculations of hadron masses. We argue that a detailed comparison of random matrix theory and lattice calculations allows for a precise determination of such corrections. We estimate the relative size of the m log(m), m, and m^2 corrections to the chiral condensate for quenched SU(2).
The chirality operators for Heisenberg spin systems
The ground state of closed Heisenberg spin chains with an odd number of sites has a chiral degeneracy, in addition to a two-fold Kramers degeneracy. A non-zero chirality implies that the spins are not coplanar, and is a measure of handedness. The chirality operator, which can be treated as a spin-1/2 operator, is explicitly constructed in terms of the spin operators, and is given as commutator of permutation operators. (author). 3 refs
Chiral symmetry breaking and monopoles
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...
Chiral symmetry and functional integral
Gamboa Saravi, R.E.; Muschietti, M.A.; Schaposnik, F.A.; Solomin, J.E.
1984-10-15
The change in the fermionic functional integral measure under chiral rotations is analyzed. Using the zeta-function method, the evaluation of chiral Jacobians to theories including non-hermitian Dirac operators D, can be extended in a natural way. (This being of interest, for example, in connection with the Weinberg-Salam model or with the relativistic string theory). Results are compared with those obtained following other approaches, the possible discrepancies are analyzed and the equivalence of the different methods under certain conditions on D is proved. Also shown is how to compute the Jacobian for the case of a finite chiral transformation and this result is used to develop a sort of path-integral version of bosonization in d = 2 space-time dimensions. This result is used to solve in a very simple and economical way relevant d = 2 fermionic models. Furthermore, some interesting features in connection with the theta-vacuum in d = 2,4 gauge theories are discussed.
Lateral chirality-sorting optical forces
Hayat, Amaury; Mueller, J. P. Balthasar; Capasso, Federico
2015-01-01
The transverse component of the spin angular momentum of evanescent waves gives rise to lateral optical forces on chiral particles, which have the unusual property of acting in a direction in which there is neither a field gradient nor wave propagation. Because their direction and strength depends on the chiral polarizability of the particle, they act as chirality-sorting and may offer a mechanism for passive chirality spectroscopy. The absolute strength of the forces also substantially exceeds that of other recently predicted sideways optical forces. PMID:26453555
Implications of Local Chiral Symmetry Breaking
La, H S
2003-01-01
The spontaneous symmetry breaking of a local chiral symmetry to its diagonal vector symmetry naturally realizes a complete geometrical structure more general than that of Yang-Mills (YM) theory, rather similar to that of gravity. A good example is the Quantum Chromodynamics (QCD) with respect to the Chiral Color model. Also, a new anomaly-free particle content for a Chiral Color model is introduced: the Chiral Color can be realized without introducing whole new generations of quarks and leptons, but by simply enlarging each generation with new exotic fermions.
The Optical Chirality Flux as a Useful Far-Field Probe of Chiral Near Fields
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.
Scaling behaviour of the effective chiral action and stability of the chiral soliton
The effective chiral action is evaluated within a novel improved heat-kernel expansion, which includes gradients of the chiral field in a non-perturbative way. The exact scaling behaviour of the effective action of a localized chiral field with respect to changing its spatial size is found. From this it is proved that the radiatively induced derivative terms cannot absolutely stabilize the chiral soliton against collapsing. The collapsing of the soliton is, however, accompanied by a vanishing of the baryon charge. It is argued that the effective chiral action constrained to a fixed baryon number may still admit stable soliton configurations. (orig.)
Synthesis and Chiral Recognition of a New Type of Chiral Calix[4]arene Derivatives
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.
Chirally-modified metal surfaces: energetics of interaction with chiral molecules.
Dementyev, Petr; Peter, Matthias; Adamovsky, Sergey; Schauermann, Swetlana
2015-09-21
Imparting chirality to non-chiral metal surfaces by adsorption of chiral modifiers is a highly promising route to create effective heterogeneously catalyzed processes for the production of enantiopure pharmaceuticals. One of the major current challenges in heterogeneous chiral catalysis is the fundamental-level understanding of how such chirally-modified surfaces interact with chiral and prochiral molecules to induce their enantioselective transformations. Herein we report the first direct calorimetric measurement of the adsorption energy of chiral molecules onto well-defined chirally-modified surfaces. Two model modifiers 1-(1-naphthyl)ethylamine and 2-methylbutanoic acid were used to impart chirality to Pt(111) and their interaction with propylene oxide was investigated by means of single-crystal adsorption calorimetry. Differential adsorption energies and absolute surface uptakes were obtained for the R- and S-enantiomers of propylene oxide under clean ultrahigh vacuum conditions. Two types of adsorption behavior were observed for different chiral modifiers, pointing to different mechanisms of imparting chirality to metal surfaces. The results are analyzed and discussed in view of previously reported stereoselectivity of adsorption processes. PMID:26256836
Gold-plated moments of nucleon structure functions in baryon chiral perturbation theory
Lensky, Vadim; Pascalutsa, Vladimir
2014-01-01
We obtain leading- and next-to-leading order predictions of chiral perturbation theory for several prominent moments of nucleon structure functions. These free-parameter free results turn out to be in overall agreement with the available empirical information on all of the considered moments, in the region of low-momentum transfer ($Q^2 < 0.3$ GeV$^2$). Especially surprising is the situation for the $\\delta_{LT}$ moment, which thus far was not reproducible for proton and neutron simultaneously in chiral perturbation theory. This problem, known as the "$\\delta_{LT}$ puzzle," is not seen in the present calculation.
Pion Form Factor in Chiral Limit of Hard-Wall AdS/QCD Model
Anatoly Radyushkin; Hovhannes Grigoryan
2007-12-01
We develop a formalism to calculate form factor and charge density distribution of pion in the chiral limit using the holographic dual model of QCD with hard-wall cutoff. We introduce two conjugate pion wave functions and present analytic expressions for these functions and for the pion form factor. They allow to relate such observables as the pion decay constant and the pion charge electric radius to the values of chiral condensate and hard-wall cutoff scale. The evolution of the pion form factor to large values of the momentum transfer is discussed, and results are compared to existing experimental data.
Hydrodynamics of Liquids of Chiral Molecules and Suspensions Containing Chiral Particles
Andreev, A. V.; Son, D. T.; Spivak, B.
2010-05-01
We obtain hydrodynamic equations describing a fluid consisting of chiral molecules or a suspension of chiral particles in a Newtonian fluid. The hydrodynamic velocity and stresses arising in a flowing chiral liquid have components that are forbidden by symmetry in a Newtonian liquid. For example, a chiral liquid in a Poiseuille flow between parallel plates exerts forces on the plates, which are perpendicular to the flow. A generic flow results in spatial separation of particles of different chirality. Thus even a racemic suspension will exhibit chiral properties in a generic flow. A suspension of particles of random shape in a Newtonian liquid is described by equations which are similar to those describing a racemic mixture of chiral particles in a liquid.
Formation of Enhanced Uniform Chiral Fields in Symmetric Dimer Nanostructures
Tian, Xiaorui; Sun, Mengtao
2015-01-01
Chiral fields with large optical chirality are very important in chiral molecules analysis, sensing and other measurements. Plasmonic nanostructures have been proposed to realize such super chiral fields for enhancing weak chiral signals. However, most of them cannot provide uniform chiral near-fields close to the structures, which makes these nanostructures not so efficient for applications. Plasmonic helical nanostructures and blocked squares have been proved to provide uniform chiral near-fields, but structure fabrication is a challenge. In this paper, we show that very simple plasmonic dimer structures can provide uniform chiral fields in the gaps with large enhancement of both near electric fields and chiral fields under linearly polarized light illumination with polarization off the dimer axis at dipole resonance. 30 times of volume averaged chiral field enhancement is gotten in the whole gap. Chiral fields with opposite handedness can be obtained simply by changing the polarization to the other side of...
A spectral route to determining chirality
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...
Is chiral symmetry manifested in nuclear structure?
Furnstahl, R. J.; Schwenk, A
2010-01-01
Spontaneously broken chiral symmetry is an established property of low-energy quantum chromodynamics, but finding direct evidence for it from nuclear structure data is a difficult challenge. Indeed, phenomenologically successful energy-density functional approaches do not even have explicit pions. Are there smoking guns for chiral symmetry in nuclei?
Partial quenching and chiral symmetry breaking
Creutz, Michael
2014-01-01
Partially quenched chiral perturbation theory assumes that valence quarks propagating on gauge configurations prepared with sea quarks of different masses will form a chiral condensate as the valence quark mass goes to zero. I present a counterexample involving non-degenerate sea quarks where the valence condensate does not form.
Generalized electromagnetic fields in a chiral medium
Bisht, P S [Department of Physics, Kumaun University, Soban Singh Jeena Campus, Almora-263601 (Uttarakhand) (India); Singh, Jivan [Department of Physics, Govt. Post Graduate College, Pithoragarh (Uttarakhand) (India); Negi, O P S [Department of Physics, Kumaun University, Soban Singh Jeena Campus, Almora-263601 (Uttarakhand) (India)
2007-09-14
The time-dependent Dirac-Maxwell's equations in the presence of electric and magnetic sources are reformulated in a chiral medium, and the solutions for the classical problem are obtained in a unique, simple and consistent manner. The quaternion reformulation of generalized electromagnetic fields in the chiral medium has also been discussed in a compact, simple and consistent manner.
LINEARLY POLARIZED PROBES OF SURFACE CHIRALITY
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
Chiral Anomaly in Toroidal Carbon Nanotubes
Sasaki, K.
2001-01-01
It is pointed out that the chiral anomaly in 1+1 dimensions should be observed in toroidal carbon nanotubes on a planar geometry with varying magnetic field. We show that the chiral anomaly is closely connected with the persistent current in a one-dimensional metallic ring.
Chirally-sensitive electron-molecule interactions
Dreiling, J. M.; Gay, T. J.
2015-09-01
All molecular forms of life have chemically-specific handedness. However, the origin of these asymmetries is not understood. A possible explanation was suggested by Vester and Ulbricht immediately following the discovery of parity violation in 1957: chiral beta radiation in cosmic rays may have preferentially destroyed one enantiomeric form of various biological precursors. In the experiments reported here, we observed chiral specificity in two electron- molecule interactions: quasi-elastic scattering and dissociative electron attachment. Using low- energy longitudinally spin-polarized (chiral) electrons as substitutes for beta rays, we found that chiral bromocamphor molecules exhibited both a transmission and dissociative electron attachment rate that depended on their handedness for a given direction of incident electron spin. Consequently, these results, especially those with dissociative electron attachment, connect the universal chiral asymmetry of the weak force with a molecular breakup process, thereby demonstrating the viability of the Vester-Ulbricht hypothesis.
Radiative meson decays in chiral perturbation theory
Radiative meson decays are a fertile field for chiral perturbation theory. Chiral symmetry together with gauge invariance yield stringent constraints on radiative decay amplitudes. In addition to predicting decay rates and spectra, the chiral approach allows for a unified description of CP violation in radiative K decays. The chiral viewpoint in the recent controversy over the magnitude of two-photon exchange in the decay KL→ π0e+e- is exposed. The radiative decay η→π0γγ is discussed as an intriguing case where the leading result of chiral perturbation theory seems to be too small by two orders of magnitude in rate. 32 refs., 3 figs. (Author)
Principal chiral model on superspheres
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 S3verticalstroke2, 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.)