WorldWideScience

Sample records for string orchestra tips

  1. Sa’Unine String Orchestra, Orkes Geseknya Indonesia

    Directory of Open Access Journals (Sweden)

    Ranti - Rachmawanti

    2012-04-01

    Full Text Available ABSTRACT   This article explains the result of Sa’Unine String Orchestra as one of Indonesian orchestras in popular culture. Main idea of this research is to uncover and describe the characteristic, func- tion, and role of Sa’Unine String Orchestra within the popular culture in Indonesia. This research used qualitative method with ethnographical approaches to identify all facts that discovered during research. The conclusions of this research show that Sa’Unine String Orchestra moves in two ways, there are; the idealism which had a vision to create a real Indonesian string orchestra and a part of music industry. At the end, these two ways are connected to each other because of the earnings of those. Music industry becomes a support factor which create the idealism of Sa’Unine String Or- chestra to be an Indonesian String Orchestra.   Keywords: String Orchestra, Music, Popular Culture.

  2. Grieg: Works for String Orchestra. Gothenburg Symphony Orchestra, Neeme Järvi / Sanders, Alan

    Index Scriptorium Estoniae

    Sanders, Alan

    1993-01-01

    Uuest heliplaadist "Grieg: Works for String Orchestra. Gothenburg Symphony Orchestra, Neeme Järvi. CD 437 520 - 2GH Grieg: Land Sighting, Op.32, Olav Trygvason, Op.50, Per Gynt Suites N1,Op.46, N2,Op.55. Randi Stene, Anne Gjevang, Hakan Hagegard, Gothenburg Symphony Chorus, Gothenburg Symphony Orchestra, Neeme Järvi. CD 437 523 - 2 GH

  3. Gender Association with Stringed Instruments: A Four-Decade Analysis of Texas All-State Orchestras

    Science.gov (United States)

    Baker, Vicki D.

    2012-01-01

    The purpose of this study was to track the gender makeup of the five string sections (Violin 1, Violin 2, Viola, Cello, and String Bass) of Texas Music Educators Association (TMEA) All-State Orchestras from 1971 to 2010, to determine if a clear gender stereotype was evident in any of the sections and if there had been a trend towards a change in…

  4. Bowing in the Right Direction: Hiland Mountain Correctional Center Women's String Orchestra Programme

    Science.gov (United States)

    Warfield, Duane

    2010-01-01

    The Hiland Mountain Correctional Center, a 400-bed facility for multi-level adult female offenders in Eagle River, Alaska, offers a unique educational programme to its prisoners: an orchestra. Founded in 2003, by volunteer Pati Crofut, orchestra membership grew from eight to 22 female offenders between 2003 and 2009. Crofut has devoted her time…

  5. United nations Orchestra

    CERN Multimedia

    MusiClub

    MusiClub United nations Orchestra www.ungenevaorchestra.ch An organizing committee has taken the initiative to create an Orchestra of the united nations at Geneva. In the context of this initiative, musicians in the following categories are invited to become members of the Orchestra and the Association: Active or retired staff of International organizations in Geneva; Active or retired employees of Permanent Missions to the United Nations at Geneva; as well as children and spouses of the above persons. For enrolment or for additional information, please contact: un.orchestra@yahoo.com

  6. METHODOLOGICAL PRINCIPLES OF FORMING REPERTOIRE OF STUDENTS’ FOLK INSTRUMENTAL ORCHESTRA

    Directory of Open Access Journals (Sweden)

    Mykola Pshenychnykh

    2016-11-01

    Full Text Available One of the main aspects of forming future music teachers’ professional competence, connected with mastering professional musical and performing skills in the course “Orchestra Class” and realized in the activity of students’ performing group, is revealed. Nowadays the problem of creative personality development is relevant, as creative future music art teachers freely orient themselves and guide pupils students in today's cultural environment, music and media space, have a strong musical taste and aesthetic guidelines. The music genre groups have been characterized in the article. It is thought that these groups are the traditional components of repertoire of folk and orchestra student groups: arrangements of folk tunes; works of Ukrainian and world classics, orchestrated for the folk groups, taking into account each orchestra performing possibilities; works by contemporary authors, written specifically for the orchestra of folk instruments. The main methodological principles of selecting the repertoire for the student orchestra of folk instruments are disclosed, including: technical, artistic and performing capabilities of student groups; involvement of works of different genres into the repertoire; correspondence of orchestra scores to instrumental composition of the student orchestra, and their correction if it is necessary; selecting works, whose performing arouses interest of the student audience; using the experience of the leading professional ensembles of folk instruments; constant updating the orchestra's repertoire. In the conclusion the author emphasizes that taking into account the methodological tips helps solve the main tasks within the course of “Orchestra Class”. These tips are the following: students’ acquaintance with the history of foundation, composition, ways of musicianship, technique of playing the instrument of folk instrument orchestra and acquaintance with specific orchestral music; development of all

  7. Differences in Myers-Briggs Personality Types among High School Band, Orchestra, and Choir Members

    Science.gov (United States)

    MacLellan, Christin Reardon

    2011-01-01

    The purpose of this study was to explore personality type differences among high school band, string orchestra, and choir students according to ensemble membership. Participants (N = 355) were high school students who had participated in their school's band, orchestra, or choir for 1 year or more. The author administered the Myers-Briggs Type…

  8. Eestisse saabub Cinematic Orchestra

    Index Scriptorium Estoniae

    2003-01-01

    Briti nu-jazzi viljeleva ansambli Cinematic Orchestra kontsertidest Tartus Vanemuise kontserdimajas 24. sept. ja Tallinnas Sakala keskuses 25.sept. kontserdiagentuuri FBI üritusteseeria "Jazz'n Motion" raames. Esitletakse grupi viimaste albumit "Man With A Movie Camera", mis on muusika Vene režissööri Dziga Vertovi samanimelisele avangardsele ja dokumentaalsele tummfilmile aastast 1929

  9. Orchestrating Your Cloud Orchestra

    OpenAIRE

    Hindle, Abram

    2015-01-01

    Cloud computing potentially ushers in a new era of computer music performance with exceptionally large computer music instruments consisting of 10s to 100s of virtual machines which we propose to call a `cloud-orchestra'. Cloud computing allows for the rapid provisioning of resources, but to deploy such a complicated and interconnected network of software synthesizers in the cloud requires a lot of manual work, system administration knowledge, and developer/operator skills. This is a barrier ...

  10. The Picture Brightens (Slightly) for String Programs

    Science.gov (United States)

    Olson, Cathy Applefeld

    2010-01-01

    It may not be the best of times for the school's string and orchestra programs, but things certainly are looking up. This article focuses on a recent report which cites the numerous positives, including an increase in the number of districts offering strings classes, a greater variety in the racial mix of strings students, and a less drastic…

  11. The Orchestra as a Laboratory

    DEFF Research Database (Denmark)

    Paunova, Minna; Velikova, Silviya Svejenova

    with learning in these and other organizations. Zooming in on a critical case of a performance arts’ organization–an orchestra-cum-laboratory–our study seeks to advance understanding of generative forms of organizing for individual and organizational learning and creativity. Unlike traditional orchestras...... for which performance is an end and rehearsing a means, for the orchestra-cum-laboratory rehearsing is an end in itself, satisfying musicians’ drives to learn and create. We are interested to advance understanding of why and how a creative collective operates as a learning-driven performance arts...... organization, and to what consequences. A strategy of in-betweenness, namely organizing in between an orchestra and a laboratory, is adopted to find balance between learning and performing. Yet, in-betweenness is not without its tensions. Our study demonstrates how orchestra members’ growth needs lead them...

  12. The Orchestra as a Laboratory

    DEFF Research Database (Denmark)

    Paunova, Minna; Velikova, Silviya Svejenova

    2017-01-01

    with learning in these and other organizations. Zooming in on a critical case of a performance arts’ organization–an orchestra-cum-laboratory–our study seeks to advance understanding of generative forms of organizing for individual and organizational learning and creativity. Unlike traditional orchestras...... for which performance is an end and rehearsing a means, for the orchestra-cum-laboratory rehearsing is an end in itself, satisfying musicians’ drives to learn and create. We are interested to advance understanding of why and how a creative collective operates as a learning-driven performance arts...... organization, and to what consequences. A strategy of in-betweenness, namely organizing in between an orchestra and a laboratory, is adopted to find balance between learning and performing. Yet, in-betweenness is not without its tensions. Our study demonstrates how orchestra members’ growth needs lead them...

  13. Audiograms of symphony orchestra musicians

    DEFF Research Database (Denmark)

    Obeling, Lise; Poulsen, Torben

    1998-01-01

    performed during rehearsal and during concerts in the four orchestras with a sound level meter placed in various instrument groups. At the same time a noise dose meter was used to evaluate the dose perceived by specific orchestra members.The average audiogram showed a decrease at higher frequencies similar......, which takes account of the number of years at work, the number of playing hours per week, and the average sound level in the orchestra for the instrument group. In almost all cases the measured audiograms looked better than the predictions from ISO 1999.It may be concluded from this investigation...

  14. Strauss: Metamorphosen for 23 solo strings / Michael Kennedy

    Index Scriptorium Estoniae

    Kennedy, Michael

    1990-01-01

    Uuest heliplaadist "Strauss: Metamorphosen for 23 solo strings, Tod und Verklärung, Op. 24, Drei Hymnen, Op.71. Felicity Lott (sop.), Scottish National Orchestra, Neeme Järvi" Chandos ABRD 1374. ABTD 1374. CHAN 8734

  15. The Orchestra as a Laboratory

    DEFF Research Database (Denmark)

    Paunova, Minna; Velikova, Silviya Svejenova

    and their work under pressure. While their resemblance with bureaucratic and professional service organizations has been acknowledged, they have been found also akin to coordinated internal networks of multiple identities (Glynn, 2000; Karmowska & Child, 2014). However, scholars have depicted orchestras...... collectives, such as teams in management and education, have demonstrated interesting tensions between learning and performing (Bunderson & Suttcliffe, 2003; Paunova & Lee, 2016)....

  16. Catching a Glimpse of the Future: One Year on in a Youth String Project

    Science.gov (United States)

    Power, Anne M.; Powell, Sarah J.

    2016-01-01

    The provision of musical experiences for youth, especially in low socio-economic areas (SES), requires funded support and imaginative resourcing. This paper presents data from the Penrith (NSW Australia) Youth String Program offered in partnership by the Australian Chamber Orchestra (ACO), Penrith Symphony Orchestra (PSO) and The Joan Sutherland…

  17. Are We Teaching Our String Students to Fear? Orchestra.

    Science.gov (United States)

    Mishra, Jennifer

    1994-01-01

    Contends that many violin and viola students develop preferences based on fear of using more difficult fingering techniques. Recommends that students be exposed to advanced techniques earlier in a matter-of-fact approach. Includes a list of four books recommended for further reading. (CFR)

  18. Grieg: Songs and dramatic works with orchestra. / Alan Blyth

    Index Scriptorium Estoniae

    Blyth, Alan

    1993-01-01

    Uuest heliplaadist "Grieg: Songs and dramatic works with orchestra. Barbara Bonney, Randi Stene, Hakan Hagegard, Ruth Tellefsen, Gothenburg Symphony Chorus and Orchestra, Neeme Järvi." CD 437 519 - 2GH

  19. Schnittke: Symphony N3. Stockholm Philharmonic Orchestra / David J. Fanning

    Index Scriptorium Estoniae

    Fanning, David J.

    1990-01-01

    Uuest heliplaadist "Schnittke: Symphony N3. Stockholm Philharmonic Orchestra, Eri Klas. BIS/ Conifer CD 477 Schnittke: Concerto Grosso N4, Symphony N5. Gothenburg Symphony Orchestra, Neeme Järvi" BIS/ Conifer CD 427

  20. The Effects of Specific Practice Strategy Use on University String Players' Performance

    Science.gov (United States)

    Sikes, Paul L.

    2013-01-01

    The purpose of this study was to determine the effects of specific practice strategy use on university string players' performance. Participants ('N" = 40) volunteered for the study and were string players enrolled in orchestra at a major research university. Within a pretest-posttest designed study, participants were assigned to one of four…

  1. Starting a Community Musical Theatre Orchestra

    Science.gov (United States)

    Sorenson, Burke

    2007-01-01

    Musical theatre is one of the great genres of music, yet very few community theatres use live music to accompany their productions. Sadly, many community theatres that formerly employed pit orchestras are replacing them with electronic music. Some producers would welcome live music, but they worry about the potential cost. There are so many…

  2. Sound Exposure of Symphony Orchestra Musicians

    DEFF Research Database (Denmark)

    Schmidt, Jesper Hvass; Pedersen, Ellen Raben; Juhl, Peter Møller

    2011-01-01

    Background: Assessment of sound exposure by noise dosimetry can be challenging especially when measuring the exposure of classical orchestra musicians where sound originate from many different instruments. A new measurement method of bilateral sound exposure of classical musicians was developed a...

  3. The Virtual Orchestra: Technical and Creative Issues

    Science.gov (United States)

    BIANCHI, F. W.; CAMPBELL, R. H.

    2000-04-01

    The interactive multi-channel computer music system known as the Virtual Orchestra has been used several times in professional opera and theater as an alternative to a live pit orchestra. The technical issues associated with this emerging technology, and the logistical problems of implementing it are discussed. In addition, this paper describes the equally important issues regarding the creative impact this will have on the industry. In particular, this paper explores the role of the musician/technologist and suggests that many of the fundamental premises of opera production will change as the industry begins to retool. This would include the way opera is rehearsed and performed, how it is created and disseminated, and how it will adjust to changing demographics.

  4. Hearing ability in Danish symphony orchestra musicians

    DEFF Research Database (Denmark)

    Obeling, Lise; Poulsen, Torben

    1999-01-01

    equipment placed in various instrument groups. The average audiogram showed a decrease at higher frequencies similar to an age-related hearing loss. Each audiogram was corrected for the age of the person by means of the median from ISO 7029 and the average audiogram from these age-corrected individual...... audiograms showed no signs of hearing loss. The audiograms were also compared to the expected audiograms from ISO 1999, which takes account of the number of years at work, the number of playing hours per week, and the average sound level in the orchestra for the instrument group. In almost all cases...... the measured audiograms looked better than the predictions from ISO 1999. It may be concluded from this investigation that musicians cannot be expected to get pronounced audiometric hearing losses from playing in a symphony orchestra. It should be noted, though, that the data material is limited...

  5. Chopin: Concerto for piano and orchestra No. 2 in F minor / Christopher Headington

    Index Scriptorium Estoniae

    Headington, Christopher

    1992-01-01

    Uuest heliplaadist "Chopin: Concerto for piano and orchestra No. 2 in F minor, Op. 21; Schumann: Concerto for piano and orchestra in A minor Op. 54. Philharmonia Orchestra, Neeme Järvi". Chandos CHAN9061 (62 minutes:DDD)

  6. Investigation of symphony orchestra musicians' use of hearing protectors

    DEFF Research Database (Denmark)

    Poulsen, Torben; Koskinen, Heli

    2010-01-01

    A questionnaire study was performed about the use of hearing protectors in Danish symphony orchestras. The musicians in three Danish symphony orchestras were asked to complete a questionnaire about their use of hearing protection. A total of 146 musicians filled in the questionnaire. Results show...... an investigation is performed about the use of hearing aids as hearing protectors by symphony orchestra musicians. Preliminary results from this investigation will be presented at the conference....

  7. String test

    Science.gov (United States)

    Duodenal parasites test; Giardia - string test ... To have this test, you swallow a string with a weighted gelatin capsule on the end. The string is pulled out 4 hours later. Any bile , blood, or mucus attached to ...

  8. From "Hack to Hallé"--Making a Robot Orchestra for the Hallé Orchestra

    Science.gov (United States)

    Moseley, Ainsley; White, Stephanie; Knowles, Mike

    2017-01-01

    As part of the celebration of Manchester being the European City of Science 2016, schools across the City were invited to take part in a Citizen-Engineering project, which set out a quest to make a recycled robot orchestra. It is a unique project, which is an experiment itself--to bring people together to create, collaborate and care for the…

  9. Liszt. Concertos for Piano and Orchestra / Bryce Morrison

    Index Scriptorium Estoniae

    Morrison, Bryce

    1995-01-01

    Uuest heliplaadist "Liszt. Concertos for Piano and Orchestra - Nr. 1 in E flat, S124, Nr. 2 in a, S125. Mazeppa S100. Les Preludes, S97. Suisse Romande Orchestra, Neeme Järvi." Chandos CD CHAN 9360 (72 minutes)

  10. Replacing the Orchestra? - The Discernibility of Sample Library and Live Orchestra Sounds.

    Directory of Open Access Journals (Sweden)

    Reinhard Kopiez

    Full Text Available Recently, musical sounds from pre-recorded orchestra sample libraries (OSL have become indispensable in music production for the stage or popular charts. Surprisingly, it is unknown whether human listeners can identify sounds as stemming from real orchestras or OSLs. Thus, an internet-based experiment was conducted to investigate whether a classic orchestral work, produced with sounds from a state-of-the-art OSL, could be reliably discerned from a live orchestra recording of the piece. It could be shown that the entire sample of listeners (N = 602 on average identified the correct sound source at 72.5%. This rate slightly exceeded Alan Turing's well-known upper threshold of 70% for a convincing, simulated performance. However, while sound experts tended to correctly identify the sound source, participants with lower listening expertise, who resembled the majority of music consumers, only achieved 68.6%. As non-expert listeners in the experiment were virtually unable to tell the real-life and OSL sounds apart, it is assumed that OSLs will become more common in music production for economic reasons.

  11. Replacing the Orchestra? - The Discernibility of Sample Library and Live Orchestra Sounds.

    Science.gov (United States)

    Kopiez, Reinhard; Wolf, Anna; Platz, Friedrich; Mons, Jan

    2016-01-01

    Recently, musical sounds from pre-recorded orchestra sample libraries (OSL) have become indispensable in music production for the stage or popular charts. Surprisingly, it is unknown whether human listeners can identify sounds as stemming from real orchestras or OSLs. Thus, an internet-based experiment was conducted to investigate whether a classic orchestral work, produced with sounds from a state-of-the-art OSL, could be reliably discerned from a live orchestra recording of the piece. It could be shown that the entire sample of listeners (N = 602) on average identified the correct sound source at 72.5%. This rate slightly exceeded Alan Turing's well-known upper threshold of 70% for a convincing, simulated performance. However, while sound experts tended to correctly identify the sound source, participants with lower listening expertise, who resembled the majority of music consumers, only achieved 68.6%. As non-expert listeners in the experiment were virtually unable to tell the real-life and OSL sounds apart, it is assumed that OSLs will become more common in music production for economic reasons.

  12. String theory

    International Nuclear Information System (INIS)

    Chan Hongmo.

    1987-10-01

    The paper traces the development of the String Theory, and was presented at Professor Sir Rudolf Peierls' 80sup(th) Birthday Symposium. The String theory is discussed with respect to the interaction of strings, the inclusion of both gauge theory and gravitation, inconsistencies in the theory, and the role of space-time. The physical principles underlying string theory are also outlined. (U.K.)

  13. Hearing loss among classical-orchestra musicians

    Directory of Open Access Journals (Sweden)

    Esko Toppila

    2011-01-01

    Full Text Available This study intended to evaluate classical musicians′ risk of hearing loss. We studied 63 musicians from four Helsinki classical orchestras. We measured their hearing loss with an audiometer, found their prior amount of exposure to sound and some individual susceptibility factors with a questionnaire, measured their present sound exposure with dosimeters, and tested their blood pressure and cholesterol levels, then compared their hearing loss to ISO 1999-1990′s predictions. The musicians′ hearing loss distribution corresponded to that of the general population, but highly exposed musicians had greater hearing loss at frequencies over 3 kHz than less-exposed ones. Their individual susceptibly factors were low. Music deteriorates hearing, but by less than what ISO 1999-1990 predicted. The low number of individual susceptibility factors explained the difference, but only reduced hearing loss and not the prevalence of tinnitus.

  14. Hyperbolic strings

    International Nuclear Information System (INIS)

    Popov, A.D.

    1991-01-01

    We introduce hyperbolic strings as closed bosonic strings with the target space R d-1,1 xT q+1,1 which has an additional time-like dimension in the internal space. The Fock spaces of the q-parametric family of standard bosonic, fermionic and heterotic strings with the target spaces of dimension n≤d+q are shown to be embedded into the Fock space of hyperbolic strings. The condition of the absence of anomaly fixes d and q for all three types of strings written in a bosonized form. (orig.)

  15. TBT recommends : Vera Bila. The No Smoking Orchestra. Robert Plant

    Index Scriptorium Estoniae

    2005-01-01

    Mustlasansambli Kale ja Vera Bila kontserdist 8. apr Tallinnas. Bosnia filmirežissööri Emir Kusturica ja tema ansambli No Smoking Orchestra kontserdist 12. apr. Riias. Inglise rocklaulja Robert Planti kontserdist 10. apr. Vilniuses

  16. Bowed Strings

    Science.gov (United States)

    Rossing, Thomas D.; Hanson, Roger J.

    In the next eight chapters, we consider some aspects of the science of bowed string instruments, old and new. In this chapter, we present a brief discussion of bowed strings, a subject that will be developed much more thoroughly in Chap. 16. Chapters 13-15 discuss the violin, the cello, and the double bass. Chapter 17 discusses viols and other historic string instruments, and Chap. 18 discusses the Hutchins-Schelleng violin octet.

  17. An Orchestra's Guide to the Universe

    Science.gov (United States)

    Harrus, I.; RIME Arthur Bloom Collaboration

    2005-12-01

    We describe here an interdisciplinary program that combines astronomy and music in a unique and unprecedented fashion. This is an intensive program in which students prepare for and perform with a professional orchestra. For many of its participants, it is a life-changing experience. For us, it is a conduit for developing, implementing and disseminating truly innovative and interdisciplinary science education and outreach. The team, headed by composer Arthur Bloom, who created the original and highly successful music program, includes astronomers, teachers, educators, and evaluators. We are working in collaboration with a school in Berwins Heights and with graduate students in astronomy from the University of Maryland in College Park under the supervision of Cole Miller. The evaluation of the program is done under the supervision of Hiro Yoshikawa (Harvard University). The program received seed funding from an IDEAS grant awarded to Arthur Bloom in 2003. This unique collaboration provides an opportunity to develop innovative and interdisciplinary educational and outreach materials, leverage investment and broadly disseminate our results, share costs, link with school systems, target underserved and underrepresented populations, cultivate new sources of media attention, and enhance interest and learning in astronomy.

  18. Bosonic strings

    CERN Document Server

    Jost, Jürgen

    2007-01-01

    This book presents a mathematical treatment of Bosonic string theory from the point of view of global geometry. As motivation, Jost presents the theory of point particles and Feynman path integrals. He provides detailed background material, including the geometry of Teichmüller space, the conformal and complex geometry of Riemann surfaces, and the subtleties of boundary regularity questions. The high point is the description of the partition function for Bosonic strings as a finite-dimensional integral over a moduli space of Riemann surfaces. Jost concludes with some topics related to open and closed strings and D-branes. Bosonic Strings is suitable for graduate students and researchers interested in the mathematics underlying string theory.

  19. Cosmological Quantum String Vacua and String-String Duality

    OpenAIRE

    Rey, Soo-Jong

    1996-01-01

    Implications of string-string dualities to cosmological string vacua are discussed. Cosmological vacua of classical string theories comprise of disjoint classses mapped one another by scale-factor T-duality. Each classes are, however, afflicted with initial/final cosmological singularities. It is argued that quantum string theories and string-string dualities dramatically resolve these cosmological singularities out so that disjoint classical cosmological vacua are continuously connected in a...

  20. Concert | United Nations Orchestra at CERN | 19 September

    CERN Multimedia

    2014-01-01

    The United Nations Orchestra will give a concert on the occasion of CERN’s 60th anniversary.   Under the baton of conductor and artistic director Antoine Marguier, the Orchestra will have the pleasure to accompany the soloist Maestro Matteo Fedeli, who, under the patronage of the Permanent Mission of Italy to the United Nations, will perform on a Stradivarius violin. The programme for the concert comprises: Jacques Offenbach, Orpheus in the Underworld Overture Franz von Suppé, Poet and Peasant Overture Camille Saint-Saëns, Introduction & Rondo Capriccioso for solo violin and orchestra Georges Bizet, Carmen Suite No. 1 Franz Lehár, Gold and Silver Waltz Gioachino Rossini, William Tell Overture   Doors open at 6 p.m. The concert will take place in a marquee behind the Globe of Science and Innovation, CERN Book your ticket here.

  1. Magnetic strings

    International Nuclear Information System (INIS)

    Chaves, Max

    2006-01-01

    The conception of the magnetic string is presented as an infinitely thin bundle of magnetic flux lines. The magnetic strings are surrounded by a film of current that rotates around them, and are a solution of Maxwell's equations. The magnetic potential contains a line singularity, and its stability can be established topologically. A few comments are added on the possibility that they may exist at a cosmological scale as relics of the Big Bang. (author) [es

  2. Lattice strings

    International Nuclear Information System (INIS)

    Thorn, C.B.

    1988-01-01

    The possibility of studying non-perturbative effects in string theory using a world sheet lattice is discussed. The light-cone lattice string model of Giles and Thorn is studied numerically to assess the accuracy of ''coarse lattice'' approximations. For free strings a 5 by 15 lattice seems sufficient to obtain better than 10% accuracy for the bosonic string tachyon mass squared. In addition a crude lattice model simulating string like interactions is studied to find out how easily a coarse lattice calculation can pick out effects such as bound states which would qualitatively alter the spectrum of the free theory. The role of the critical dimension in obtaining a finite continuum limit is discussed. Instead of the ''gaussian'' lattice model one could use one of the vertex models, whose continuum limit is the same as a gaussian model on a torus of any radius. Indeed, any critical 2 dimensional statistical system will have a stringy continuum limit in the absence of string interactions. 8 refs., 1 fig. , 9 tabs

  3. Hearing Protection and Hearing Symptoms in Danish Symphony Orchestras

    DEFF Research Database (Denmark)

    Laitinen, Heli; Poulsen, Torben

    2006-01-01

    A study about hearing protectors, problems involving hearing protector usage, hearing problems and working surroundings of classical musicians was made in three Danish symphony orchestras. The questionnaire used in the study was based on a previous study, a study made in Sweden to rock musicians,...

  4. Missing Faces from the Orchestra: An Issue of Social Justice?

    Science.gov (United States)

    DeLorenzo, Lisa C.

    2012-01-01

    There is a surprising lack of black and Latino musicians in major orchestras in the United States as well as in other venues for classical music. Similarly, many American high school performing ensembles reflect the same underrepresentation. This article examines the literature on race, socioeconomic factors, and urban teaching and provides…

  5. Temporal interaction between an artificial orchestra conductor and human musicians

    NARCIS (Netherlands)

    Reidsma, Dennis; Nijholt, Antinus; Bos, Pieter

    2008-01-01

    The Virtual Conductor project concerns the development of the first properly interactive virtual orchestra conductor—a Virtual Human that can conduct a piece of music through interaction with musicians, leading and following them while they are playing. This article describes our motivation for

  6. Liszt. Concertos for Piano and Orchestra / Bryce Morrison

    Index Scriptorium Estoniae

    Morrison, Bryce

    1993-01-01

    Uuest heliplaadist "Pärt: Te Deum. Silouans Song. "My soul yearns after the Lord...". Magnificat. Berliner Messe. Estonian Philharmonic Chamber Choir, Tallinn Chamber Orchestra/Tõnu Kaljuste." ECM New Series 439 162-2 (66 minutes: DDD). Texts and translations included

  7. Singleton strings

    Energy Technology Data Exchange (ETDEWEB)

    Engquist, J. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University (Netherlands); Sundell, P. [INFN, Pisa (Italy); Scuola Normale Superiore, Pisa (Italy); Tamassia, L. [Instituut voor Theoretische Fysica, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium)

    2007-05-15

    The group theoretical structure underlying physics in anti de Sitter (AdS) spacetime is intrinsically different with respect to the flat case, due to the presence of special ultra-short representations, named singletons, that do not admit a flat space limit. The purpose of this collaboration is to exploit this feature in the study of string and brane dynamics in AdS spacetime, in particular while trying to establish a connection between String Theory in AdS backgrounds (in the tensionless limit) and Higher-Spin Gauge Theory. (orig.)

  8. Teaching Strings.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    Intended primarily for use by instrumental music teachers who do not have a major concentration in strings, this guide provides pertinent basic resources, materials, teaching--learning expectation, and a general overall guide to achievement levels at various stages of development. Discussions are presented of Choosing the Proper Method Book,…

  9. String phenomenology

    CERN Document Server

    Ibáñez, Luis E

    2015-01-01

    This chapter reviews a number of topics in the field of string phenomenology, focusing on orientifold/F-theory models yielding semirealistic low-energy physics. The emphasis is on the extraction of the low-energy effective action and possible tests of specific models at the LHC.

  10. Distortion product otoacoustic emission fine structure of symphony orchestra musicians

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    2006-01-01

    losses than puretone audiometry. The distortion product otoacoustic emission (DPOAE) fine structure is obtained when the ear is stimulated by dual tone stimuli using a high frequency resolution. It is characterized by quasi-periodic variations across frequency, as it can be observed in the hearing...... threshold microstructure also. In this study DPOAE fine structures and hearing thresholds are obtained for symphony orchestra musicians both for left and right ears and before and after the orchestra rehearsal. DPOAE fine structures are analyzed with an automatic classification algorithm, which describes...... the ripple pattern by parameters. A difference between left and right ears could be detected for the DPOAE level but not for the fine structure parameters. No difference between the measures taken before and after exposure could be observed....

  11. METHODOLOGICAL PRINCIPLES OF FORMING REPERTOIRE OF STUDENTS’ FOLK INSTRUMENTAL ORCHESTRA

    OpenAIRE

    Mykola Pshenychnykh; Volodymyr Kryvokhvostov

    2016-01-01

    One of the main aspects of forming future music teachers’ professional competence, connected with mastering professional musical and performing skills in the course “Orchestra Class” and realized in the activity of students’ performing group, is revealed. Nowadays the problem of creative personality development is relevant, as creative future music art teachers freely orient themselves and guide pupils students in today's cultural environment, music and media space, have a strong musical tast...

  12. Perancangan Interior Sekolah Musik Surabaya Symphony Orchestra Di Surabaya

    OpenAIRE

    Grace Mulyono, Liliyana Tan IGN. Ardana

    2016-01-01

    Classical music has a lot of benefits that can make more optimal brain development. Surabaya Symphony Orchestra Music School is a place to facilitate society in Surabaya to learn classical music.Many activities that can support learning classical music has not been facilitated due to the limited area, and lack of interior on SSO create interest and learning music became blocked. In accordance with Dolce concept which means “to play sweetly”, the music school design is using bright colors with...

  13. Remembering tips

    Science.gov (United States)

    Memory aids; Alzheimer disease - remembering tips; Early memory loss - remembering tips; Dementia - remembering tips ... active: Read a lot if you have trouble remembering words. Keep a dictionary close by. Take part ...

  14. Musculoskeletal problems among string instrumentalists in South Africa

    Directory of Open Access Journals (Sweden)

    Adedayo T. Ajidahun

    2017-02-01

    Full Text Available Background: Musicians who play string instruments are affected more by musculoskeletal injuries when compared to other instrument playing groups. Musculoskeletal problems are commonly found in the upper extremities and trunk. Several risk factors such as gender, practice hours and instrument played are associated with the prevalence and distribution of musculoskeletal problems among string instrumentalists. Objectives: The aim of this study was to determine the prevalence, distribution, severity and risk factors for musculoskeletal problems among string instrumentalists. Method: A cross-sectional study design using both online and paper-based questionnaires were used to collect data from string instrumentalists playing in both amateur and professional orchestras in South Africa. Results: A total of 114 string instrumentalists participated in the study, of which 86 (77% reported problems in one or more anatomic regions while 39 (35% were currently experiencing musculoskeletal problems that affected their performance. The trunk and both shoulders were the most commonly affected body regions. The majority of the participants reported the severity of the complaints as mild to moderate with aching, soreness, tingling and fatigue being the most commonly used descriptors of the symptoms of playing-related musculoskeletal problems. Conclusion: The results of this study showed that the prevalence of musculoskeletal problems that affect performance is high among string instrumentalists in South Africa. An evaluation of associated risk factors with the aim of reducing injuries may be important in improving performance.

  15. Tips for TIPS

    NARCIS (Netherlands)

    Cuijpers, C.F.

    2015-01-01

    The transjugular intrahepatic portosystemic shunt (TIPS) procedure is one of the most technically challenging procedures in interventional radiology. During the procedure, interventional radiologists (IRs) insert very thin and long instruments through a little incision in the patient’s neck. They

  16. The "Magic" String

    Science.gov (United States)

    Hoover, Todd F.

    2010-01-01

    The "Magic" String is a discrepant event that includes a canister with what appears to be the end of two strings protruding from opposite sides of it. Due to the way the strings are attached inside the canister, it appears as if the strings can magically switch the way they are connected. When one string end is pulled, the observer's expectation…

  17. String Gas Cosmology

    OpenAIRE

    Brandenberger, Robert H.

    2008-01-01

    String gas cosmology is a string theory-based approach to early universe cosmology which is based on making use of robust features of string theory such as the existence of new states and new symmetries. A first goal of string gas cosmology is to understand how string theory can effect the earliest moments of cosmology before the effective field theory approach which underlies standard and inflationary cosmology becomes valid. String gas cosmology may also provide an alternative to the curren...

  18. Rock Orchestra Alumni Reflections on the Impact of Participation in "The Lakewood Project"

    Science.gov (United States)

    Koops, Lisa Huisman; Hankins, Elizabeth A.; Scalise, David; Schatt, Matthew D.

    2014-01-01

    The purpose of this mixed-methods study was to explore the phenomenon of participation in a high school rock orchestra from the perspective of alumni. Specific research questions addressed the musicians' reflections on experiences in the rock orchestra and the perceived possible impact on their current musical and professional lives. Survey and…

  19. Stenhammer: Concerto for Piano and Orchestra No. 2 in D minor / Robert Layton

    Index Scriptorium Estoniae

    Layton, Robert

    1994-01-01

    Uuest heliplaadist "Stenhammer: Concerto for Piano and Orchestra No. 2 in D minor, Op. 23. Serenade in F, Op. 31. Florez och Blanzeflor, Op. 3... Munich Philharmonic Orchestra / Stig Westerberg; Serenade - selected comparison: Gothenburg SO, Järvi" (2/87) BIS CD 310

  20. Hearing loss in relation to sound exposure of professional symphony orchestra musicians

    DEFF Research Database (Denmark)

    Schmidt, J. H.; Pedersen, E. R.; Paarup, H. M.

    2014-01-01

    OBJECTIVES: The objectives of this study were to: (1) estimate the hearing status of classical symphony orchestra musicians and (2) investigate the hypothesis that occupational sound exposure of symphony orchestra musicians leads to elevated hearing thresholds. DESIGN: The study population...... that performing music may induce hearing loss to the same extent as industrial noise....

  1. A Systematic Inventory of Motives for Becoming an Orchestra Conductor: A Preliminary Study

    Science.gov (United States)

    Makris, Ioannis; Mullet, Etienne

    2009-01-01

    The study examined the various motives (reasons) that may have led an individual to become an orchestra conductor interpreting classical works, using Apter's (2001) Metamotivational Theory framework. Questionnaires derived from the theory, consisting of 92 possible motives for becoming an orchestra conductor, were presented to 101 orchestra…

  2. 77 FR 40515 - Safety Zone; Detroit Symphony Orchestra at Ford House Fireworks, Lake St. Clair, Grosse Pointe...

    Science.gov (United States)

    2012-07-10

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Detroit Symphony Orchestra at Ford House... Detroit Symphony Orchestra at the Ford House Fireworks. This zone will be effective and enforced from 10... Orchestra at Ford House Fireworks, Lake St. Clair, Grosse Pointe Shores, MI (a) Location. The safety zone...

  3. Closed string field theory

    International Nuclear Information System (INIS)

    Strominger, A.

    1987-01-01

    A gauge invariant cubic action describing bosonic closed string field theory is constructed. The gauge symmetries include local spacetime diffeomorphisms. The conventional closed string spectrum and trilinear couplings are reproduced after spontaneous symmetry breaking. The action S is constructed from the usual ''open string'' field of ghost number minus one half. It is given by the associator of the string field product which is non-vanishing because of associativity anomalies. S does not describe open string propagation because open string states associate and can thereby be shifted away. A field theory of closed and open strings can be obtained by adding to S the cubic open string action. (orig.)

  4. From cosmic string to superconducting string

    CERN Document Server

    Kim, H C; Lee, B K

    1999-01-01

    We consider the dynamical symmetry breaking of a chirally-invariant Nambu-Jona-Lasinio model in the background gravity of a local cosmic string. By analyzing the one-loop effective action, we show how a cosmic string at a very high energy scale forms a global superconducting string to the spontaneous chiral symmetry breaking at a low energy.

  5. Tipping Point

    Medline Plus

    Full Text Available ... death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash ... tv tip-overs. The force of a large television falling from tipping furniture can be staggering. A ...

  6. Evaluation of the noise exposure of symphonic orchestra musicians

    Directory of Open Access Journals (Sweden)

    Matilde Alexandra Rodrigues

    2014-01-01

    Full Text Available For musicians, the impact of noise exposure is not yet fully characterized. Some inconsistencies can be found in the methodology used to evaluate noise exposure. This study aims to analyze the noise exposure of musicians in a symphonic orchestra to understand their risk for hearing loss, applying the methodology proposed by ISO 9612:2009. Noise levels were monitored among musicians during the rehearsal of eight different repertoires. Test subjects were selected according to their instrument and position in the orchestra. Participants wore noise dosimeters throughout the rehearsals. A sound meter was used to analyze the exposure of the conductor. The results showed that musicians are exposed to high noise levels that can damage hearing. Brass, woodwind and percussion and timpani musicians were exposed to noise levels in excess of the upper exposure action level of 85 dB (A, while the other instrumental groups had a lower exposure action level of 80 dB (A. Percussion musicians were exposed to high peak noise levels of 135 dB (C. Sound levels varied by instrument, repertoire and position. Octave frequency analyses showed differences among musicians. This study suggests that musicians are at risk for hearing loss. There is a need for more effective guidelines applicable to all countries, which should define standardized procedures for determining musician noise exposure and should allow exposure level normalization to the year, including different repertoires.

  7. Noise exposure of musicians of a ballet orchestra

    Directory of Open Access Journals (Sweden)

    Cheng Liang Qian

    2011-01-01

    Full Text Available With over 70 dancers and its own orchestra, The National Ballet of Canada ranks amongst the world′s top dance companies. It performs three seasons annually: fall, winter and summer, plus many shows of Tchaikovsky′s Nutcracker. The 70-strong orchestra plays an average of 360 hours/year including rehearsals and performances. Rehearsals are held at two locations: one in a ballet rehearsal room with little or no absorption, and the other in an acoustically treated location. Performances are held in the Four Seasons Centre for the Performing Arts in Toronto. The present survey was done at the request of the National Ballet, since the musicians complained of excessive sound levels and were concerned about possible hearing losses. The survey was performed using five dosimeters Quest Mod 300 during 10 performances of the ballet Romeo and Juliet by Sergei Prokofiev, deemed as the noisiest in the whole repertoire. Results of the survey indicate that the noise exposure levels from only the orchestra′s activities do not present risk of hearing loss. Exposure due to other musical activities was, however, not included.

  8. Tipping Point

    Medline Plus

    Full Text Available ... en español Blog About OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point The Tipping Point by ... danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe ...

  9. Evidence for string substructure

    International Nuclear Information System (INIS)

    Bergman, O.

    1996-06-01

    The author argues that the behavior of string theory at high temperature and high longitudinal boosts, combined with the emergence of p-branes as necessary ingredients in various string dualities, point to a possible reformulation of strings, as well as p-branes, as composites of bits. He reviews the string-bit models, and suggests generalizations to incorporate p-branes

  10. The high prevalence of playing-related musculoskeletal disorders (PRMDs) and its associated factors in amateur musicians playing in student orchestras: A cross-sectional study.

    Science.gov (United States)

    Kok, Laura M; Groenewegen, Karlijn A; Huisstede, Bionka M A; Nelissen, Rob G H H; Rietveld, A Boni M; Haitjema, Saskia

    2018-01-01

    Despite the high number of amateur musicians in the general population, little is known about the musculoskeletal health of amateur musicians. Playing a musical instrument is supposed to be a risk factor for the development of musculoskeletal complaints. This study aimed to evaluate playing-related musculoskeletal disorders (PRMDs) among amateur musicians playing in student orchestras. A cross-sectional study. 357 members of eleven Dutch student orchestras across the Netherlands were included in this study. A paper-based questionnaire on PRMDs was used. Sociodemographic characteristics and PRMDs were evaluated using an adaptation of the Nordic Musculoskeletal Questionnaire (NMQ) and the music module of the Disabilities of Shoulder and Hand (DASH) questionnaire. The year prevalence of PRMDs among amateur musicians was 67.8%. Female gender, younger age, higher BMI and playing a string instrument were independently associated with a higher prevalence of PRMDs. The left shoulder was affected more frequently in violinists and violists, whereas the right hand and wrist were more frequently affected in woodwind instrumentalists. Of the subjects with PRMDs during the last week, the score of the music module of the DASH was 18.8 (6.3-31.2). This study is the first to report on PRMDs and its associated factors in a large group of amateur musicians. The prevalence of PRMDs in amateur musicians is high, however the DASH scores reflect a confined impact of these PRMDs on their functioning as a musician. Preventive measures are needed aiming at reducing PRMDs among amateur musicians.

  11. The heterotic string

    International Nuclear Information System (INIS)

    Gross, D.J.

    1986-01-01

    Traditional string theories, either bosonic or supersymmetric, came in two varieties, closed string theories and open string theories. Closed string are neutral objects which describe at low energies gravity or supergravity. Open strings have geometrically invariant ends to which charge can be attached, thereby obtaining, in addition to gravity, Yang-Mills gauge interactions. Recently a new kind of string theory was discovered--the heterotic string, which is a chiral hybrid of the closed superstring and the closed bosonic string, and which produces by an internal dynamical mechanism gauge interactions of a totally specified kind. Although this theory is found in an attempt to produce a superstring theory which would yield a low energy E/sub 8/xE/sub 8/ supersymmetric, anomaly free, gauge theory, as suggested by the anomaly cancellation mechanism of Green and Schwarz, it fits naturally into the general framework of consistent string theories

  12. Closed String Amplitudes from Gauge Fixed String Field Theory

    OpenAIRE

    Drukker, Nadav

    2002-01-01

    Closed string diagrams are derived from cubic open string field theory using a gauge fixed kinetic operator. The basic idea is to use a string propagator that does not generate a boundary to the world sheet. Using this propagator and the closed string vertex, the moduli space of closed string surfaces is covered, so closed string scattering amplitudes should be reproduced. This kinetic operator could be a gauge fixed form of the string field theory action around the closed string vacuum.

  13. Strauss, R.: Symphony in F minor, Op. 12... Tokyo Metropolitan Symphony Orchestra / David Nice

    Index Scriptorium Estoniae

    Nice, David

    1994-01-01

    Uuest heliplaadist "Strauss, R.: Symphony in F minor, Op. 12... Tokyo Metropolitan Symphony Orchestra / Hiroshi Wakasugi. Denon CD CO-75 860 (54 minutes); Symphony - comparative version: SNO, Järvi" (8/93)(CHAN) CHAN 9166

  14. Orchestral Conducting as Educational Practice: A Smallian Perspective of Relationships and Pedagogy in Youth Orchestras

    Directory of Open Access Journals (Sweden)

    Daniele Parziani

    2011-01-01

    Full Text Available In this article the author attempts a first description of his ongoing research on the pedagogy and educational philosophy which can be applied in working with the youth orchestra, based on Christopher Small's theory of musicking; the youth orchestra is seen here as a learning community, and the author attempts to redefine the relationships which are embodied and shaped within it, wishing to stir up the stagnant social relationships of the classical orchestra community. The article is particularly concerned with the power relationship between the teacher-conductor and the students, while raising questions of musical identity, hierarchy and empathy from a Smallian perspective applied to the conducting of the youth orchestra, within a concept of educational conducting.

  15. Brahms J. Hungarian Dances. London Symphony Orchestra, Neeme Järvi / Jonathan Swain

    Index Scriptorium Estoniae

    Swain, Jonathan

    1991-01-01

    Uuest heliplaadist "Brahms J. Hungarian Dances. London Symphony Orchestra, Neeme Järvi. Chandos MC ABTD 1496; CD CHAN 8885 (57 minutes). Brahms J. Hungarian Dances. Staatskapelle Berlin. Otmar Suitner." Denon CD CO- 74597 (53 minutes)

  16. Relativistic classical strings. II

    International Nuclear Information System (INIS)

    Galvao, C.A.P.

    1985-01-01

    The interactions of strings with electromagnetic and gravitational fields are extensively discussed. Some concepts of differential geometry are reviewed. Strings in Kaluza-Klein manifolds are studied. (L.C.) [pt

  17. Tipping Point

    Medline Plus

    Full Text Available ... OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point ... 24 hours a day. For young children whose home is a playground, it’s the best way to ...

  18. CPAP Tips

    Medline Plus

    Full Text Available ... a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from the U.S. Food ... 395,755 views 9:28 3 Tips for Sleeping With a CPAP - Duration: 2:02. WebMD 66, ...

  19. std::string Append

    Science.gov (United States)

    2015-10-01

    UNCLASSIFIED AD-E403 689 Technical Report ARWSE-TR-14026 STD ::STRING APPEND Tom Nealis...DATES COVERED (From – To) 4. TITLE AND SUBTITLE STD ::STRING APPEND 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...two or more strings together while developing a C++ application is a very common task. For std ::strings, there are two primary ways to achieve the

  20. Strings in the Sun?

    International Nuclear Information System (INIS)

    Chudnovsky, E.; Vilenkin, A.

    1988-01-01

    If light superconducting strings were formed in the early Universe, then it is very likely that now they exist in abundance in the interstellar plasma and in stars. The dynamics of such strings can be dominated by friction, so that they are ''frozen'' into the plasma. Turbulence of the plasma twists and stretches the strings, forming a stochastic string network. Such networks must generate particles and magnetic fields, and may play an important role in the physics of stars and of the Galaxy

  1. StringForce

    DEFF Research Database (Denmark)

    Barendregt, Wolmet; Börjesson, Peter; Eriksson, Eva

    2017-01-01

    In this paper, we present the forced collaborative interaction game StringForce. StringForce is developed for a special education context to support training of collaboration skills, using readily available technologies and avoiding the creation of a "mobile bubble". In order to play StringForce ...

  2. Dynamics of Carroll strings

    Energy Technology Data Exchange (ETDEWEB)

    Cardona, Biel [Departament d’Estructura i Constituents de la Matèriaand Institut de Ciències del Cosmos (ICCUB) Facultat de Física, Universitat de Barcelona,Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Gomis, Joaquim [Departament d’Estructura i Constituents de la Matèriaand Institut de Ciències del Cosmos (ICCUB) Facultat de Física, Universitat de Barcelona,Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Department of Physics, Faculty of Science, Chulalongkorn University,Bangkok 10330 (Thailand); Pons, Josep M. [Departament d’Estructura i Constituents de la Matèriaand Institut de Ciències del Cosmos (ICCUB) Facultat de Física, Universitat de Barcelona,Diagonal 647, E-08028 Barcelona, Catalonia (Spain)

    2016-07-11

    We construct the canonical action of a Carroll string doing the Carroll limit of a canonical relativistic string. We also study the Killing symmetries of the Carroll string, which close under an infinite dimensional algebra. The tensionless limit and the Carroll p-brane action are also discussed.

  3. Minimal open strings

    International Nuclear Information System (INIS)

    Hosomichi, Kazuo

    2008-01-01

    We study FZZT-branes and open string amplitudes in (p, q) minimal string theory. We focus on the simplest boundary changing operators in two-matrix models, and identify the corresponding operators in worldsheet theory through the comparison of amplitudes. Along the way, we find a novel linear relation among FZZT boundary states in minimal string theory. We also show that the boundary ground ring is realized on physical open string operators in a very simple manner, and discuss its use for perturbative computation of higher open string amplitudes.

  4. Cosmic strings and inflation

    International Nuclear Information System (INIS)

    Vishniac, E.T.

    1987-01-01

    We examine the compatibility of inflation with the cosmic string theory for galaxy formation. There is a general conflict between having sufficient string tension to effect galaxy formation, and reheating after inflation to a high enough temperature that strings may form in a thermal phase transition. To escape this conflict, we propose a class of models where the inflation is coupled to the string-producing field. The strings are formed late in inflation as the inflaton rolls towards its zero-temperature value. A large subset of these models have a novel large-scale distribution of galaxies that is fractal, displays biasing without dynamics or feedback mechanisms, and contains voids. (orig.)

  5. Closed Strings From Nothing

    International Nuclear Information System (INIS)

    Lawrence, Albion

    2001-01-01

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order α' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting

  6. Closed Strings From Nothing

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, Albion

    2001-07-25

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order {alpha}' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting.

  7. The arithmetic of strings

    International Nuclear Information System (INIS)

    Freund, P.G.O.

    1988-01-01

    According to the author nobody has succeeded as yet in extracting any new numbers from string theory. This paper discusses how if one cannot get new numbers from string theory, maybe one can get new strings out of number theory. Number theory is generally regarded as the purest form of mathematics. So how can it conceivably make contact with physics which aims at describing nature? The author discusses how the connecting link of these two disciplines is provided by the compact Riemann surfaces. These appear as world sheets of interacting strings. For instance, string-string scattering at the three-loop level involves the four external strings attaching themselves to a genus three compact surface

  8. Tipping Point

    Medline Plus

    Full Text Available ... Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture head ... see news reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The ...

  9. CPAP Tips

    Medline Plus

    Full Text Available ... make your opinion count. Sign in Loading... Loading... Transcript The interactive transcript could not be loaded. Loading... ... Dan Uses CPAP - Duration: 4:17. Harvard Medical School 7,950 views 4:17 Tips for building ...

  10. CPAP Tips

    Science.gov (United States)

    ... make your opinion count. Sign in Loading... Loading... Transcript The interactive transcript could not be loaded. Loading... ... Dan Uses CPAP - Duration: 4:17. Harvard Medical School 7,950 views 4:17 Tips for building ...

  11. Tipping Point

    Medline Plus

    Full Text Available ... fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash format. Almost ... accidents involving young children and furniture, appliance and tv tip-overs. The force of a large television ...

  12. Tipping Point

    Medline Plus

    Full Text Available ... impact can kill a child or cause severe injuries. About 16,000 (mostly young children) were treated in emergency rooms for tip-over related injuries in 2006, that’s about four times more injuries ...

  13. Tipping Point

    Medline Plus

    Full Text Available ... appliance child Childproofing CPSC danger death electrical fall furniture head injury product safety television tipover tv Watch ... reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The force of ...

  14. Tipping Point

    Medline Plus

    Full Text Available ... third story of a building. That kind of impact can kill a child or cause severe injuries. ... to prevent a tip-over tragedy. Share Post Facebook Twitter Google Plus Reddit Connect with Me:  Visit ...

  15. Open-closed string correspondence in open string field theory

    International Nuclear Information System (INIS)

    Baumgartl, M.; Sachs, I.

    2008-01-01

    We address the problem of describing different closed string backgrounds in background independent open string field theory: A shift in the closed string background corresponds to a collective excitation of open strings. As an illustration we apply the formalism to the case where the closed string background is a group manifold. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  16. Strings, texture, and inflation

    International Nuclear Information System (INIS)

    Hodges, H.M.; Primack, J.R.

    1991-01-01

    We examine mechanisms, several of which are proposed here, to generate structure formation, or to just add large-scale features, through either gauged or global cosmic strings or global texture, within the framework of inflation. We first explore the possibility that strings or texture form if there is no coupling between the topological theory and the inflaton or spacetime curvature, via (1) quantum creation, and (2) a sufficiently high reheat temperature. In addition, we examine the prospects for the inflaton field itself to generate strings or texture. Then, models with the string/texture field coupled to the curvature, and an equivalent model with coupling to the inflaton field, are considered in detail. The requirement that inflationary density fluctuations are not so large as to conflict with observations leads to a number of constraints on model parameters. We find that strings of relevance for structure formation can form in the absence of coupling to the inflaton or curvature through the process of quantum creation, but only if the strings are strongly type I, or if they are global strings. If formed after reheating, naturalness suggests that gauged cosmic strings correspond to a type-I superconductor. Similarly, gauged strings formed during inflation via conformal coupling ξ=1/6 to the spacetime curvature (in a model suggested by Yokoyama in order to evade the millisecond pulsar constraint on cosmic strings) are expected to be strongly type I

  17. Topics in string theory

    International Nuclear Information System (INIS)

    Neveu, A.

    1986-01-01

    There exist several string models. In the first lecture, the simplest one, the open bosonic string, which turns out to live most naturally in 26 dimensions will be described in some detail. In the second lecture, the closed bosonic strings, and the open and closed 10-dimensional strings (superstrings) are reviewed. In the third lecture, various compactification schemes which have been proposed to deal with the extra space dimensions, from 4 to 10 or 26 are dealt with; in particular, the Frenkel-Kac construction which builds non-Abelian internal symmetry groups out of the compactified dimensions, and the resulting heterotic string are described. Finally, in the fourth lecture, the important problem of the second quantization of string theories, and of the underlying gauge invariance which is responsible for the possibility of dealing, in a consistent fashion, with interacting high-spin states without negative metric is addressed. 41 references, 8 figures

  18. N = 2 string amplitudes

    International Nuclear Information System (INIS)

    Ooguri, H.

    1995-08-01

    In physics, solvable models have played very important roles. Understanding a simple model in detail teaches us a lot about more complicated models in generic situations. Five years ago, C. Vafa and I found that the closed N = 2 string theory, that is a string theory with the N = 2 local supersymmetry on the worldsheet, is classically equivalent to the self-dual Einstein gravity in four spacetime dimensions. Thus this string theory is solvable at the classical level. More recently, we have examined the N = 2 string partition function for spacial compactifications, and computed it to all order in the string perturbation expansion. The fact that such computation is possible at all suggests that the N = 2 string theory is solvable even quantum mechanically

  19. Adult Community Orchestras in Texas: Activity and Background Profiles of Participants with a Report of Organizational Standing

    Science.gov (United States)

    Brown, Kathryn Dharlene

    2016-01-01

    The purpose of this study was to identify and assess Texas community orchestras and create a demographic and musical profile of participants. This was accomplished through use of two online questionnaires. A director survey questionnaire determined the organizational status of each orchestra. The directors surveyed were leaders in these…

  20. Optimal Packed String Matching

    DEFF Research Database (Denmark)

    Ben-Kiki, Oren; Bille, Philip; Breslauer, Dany

    2011-01-01

    In the packed string matching problem, each machine word accommodates – characters, thus an n-character text occupies n/– memory words. We extend the Crochemore-Perrin constantspace O(n)-time string matching algorithm to run in optimal O(n/–) time and even in real-time, achieving a factor – speedup...... over traditional algorithms that examine each character individually. Our solution can be efficiently implemented, unlike prior theoretical packed string matching work. We adapt the standard RAM model and only use its AC0 instructions (i.e., no multiplication) plus two specialized AC0 packed string...

  1. Interpolating string field theories

    International Nuclear Information System (INIS)

    Zwiebach, B.

    1992-01-01

    This paper reports that a minimal area problem imposing different length conditions on open and closed curves is shown to define a one-parameter family of covariant open-closed quantum string field theories. These interpolate from a recently proposed factorizable open-closed theory up to an extended version of Witten's open string field theory capable of incorporating on shell closed strings. The string diagrams of the latter define a new decomposition of the moduli spaces of Riemann surfaces with punctures and boundaries based on quadratic differentials with both first order and second order poles

  2. 6d string chains

    Science.gov (United States)

    Gadde, Abhijit; Haghighat, Babak; Kim, Joonho; Kim, Seok; Lockhart, Guglielmo; Vafa, Cumrun

    2018-02-01

    We consider bound states of strings which arise in 6d (1,0) SCFTs that are realized in F-theory in terms of linear chains of spheres with negative self-intersections 1,2, and 4. These include the strings associated to N small E 8 instantons, as well as the ones associated to M5 branes probing A and D type singularities in M-theory or D5 branes probing ADE singularities in Type IIB string theory. We find that these bound states of strings admit (0,4) supersymmetric quiver descriptions and show how one can compute their elliptic genera.

  3. String theory for dummies

    CERN Document Server

    Zimmerman Jones, Andrew

    2010-01-01

    Making Everything Easier!. String Theory for Dummies. Learn:. The basic concepts of this controversial theory;. How string theory builds on physics concepts;. The different viewpoints in the field;. String theory's physical implications. Andrew Zimmerman Jones. Physics Guide, About.com. with Daniel Robbins, PhD in Physics. Your plain-English guide to this complex scientific theory. String theory is one of the most complicated sciences being explored today. Not to worry though! This informative guide clearly explains the basics of this hot topic, discusses the theory's hypotheses and prediction

  4. QCD and hadronic strings

    International Nuclear Information System (INIS)

    Cohen-Tannoudji, G.

    1989-01-01

    This series of lectures is devoted to review ot he connections between QCD and string theories. One reviews the phenomenological models leading to string pictures in non perturbative QCD and the string effects, related to soft gluon coherence, which arise in perturbative QCD. One tries to build a string theory which goes to QCD at the zero slope limit. A specific model, based on superstring theories is shown to agree with QCD four point amplitudes at the Born approximation and with one loop corrections. One shows how this approach can provide a theoretical framework to account for the phenomenological property of parton-hadron duality.(author)

  5. Heterotic cosmic strings

    International Nuclear Information System (INIS)

    Becker, Katrin; Becker, Melanie; Krause, Axel

    2006-01-01

    We show that all three conditions for the cosmological relevance of heterotic cosmic strings, the right tension, stability and a production mechanism at the end of inflation, can be met in the strongly coupled M-theory regime. Whereas cosmic strings generated from weakly coupled heterotic strings have the well-known problems posed by Witten in 1985, we show that strings arising from M5-branes wrapped around 4-cycles (divisors) of a Calabi-Yau in heterotic M-theory compactifications solve these problems in an elegant fashion

  6. Tipping Point

    Medline Plus

    Full Text Available ... 24 hours a day. For young children whose home is a playground, it’s the best way to prevent a tip-over tragedy. Share Post Facebook Twitter ... Security, and Legal Notice | Accessibility Policy | Open Government @ CPSC | ...

  7. CPAP Tips

    Medline Plus

    Full Text Available ... sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely ... Copyright Creators Advertise Developers +YouTube Terms Privacy Policy & Safety Send feedback Test new features Loading... Working... Sign ...

  8. The high prevalence of playing-related musculoskeletal disorders (PRMDs and its associated factors in amateur musicians playing in student orchestras: A cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Laura M Kok

    Full Text Available Despite the high number of amateur musicians in the general population, little is known about the musculoskeletal health of amateur musicians. Playing a musical instrument is supposed to be a risk factor for the development of musculoskeletal complaints. This study aimed to evaluate playing-related musculoskeletal disorders (PRMDs among amateur musicians playing in student orchestras.A cross-sectional study.357 members of eleven Dutch student orchestras across the Netherlands were included in this study.A paper-based questionnaire on PRMDs was used.Sociodemographic characteristics and PRMDs were evaluated using an adaptation of the Nordic Musculoskeletal Questionnaire (NMQ and the music module of the Disabilities of Shoulder and Hand (DASH questionnaire.The year prevalence of PRMDs among amateur musicians was 67.8%. Female gender, younger age, higher BMI and playing a string instrument were independently associated with a higher prevalence of PRMDs. The left shoulder was affected more frequently in violinists and violists, whereas the right hand and wrist were more frequently affected in woodwind instrumentalists. Of the subjects with PRMDs during the last week, the score of the music module of the DASH was 18.8 (6.3-31.2.This study is the first to report on PRMDs and its associated factors in a large group of amateur musicians. The prevalence of PRMDs in amateur musicians is high, however the DASH scores reflect a confined impact of these PRMDs on their functioning as a musician. Preventive measures are needed aiming at reducing PRMDs among amateur musicians.

  9. Superfermionic superconformal string model

    International Nuclear Information System (INIS)

    Kudryavtsev, V.A.

    1994-01-01

    A new approach to superconformal dynamics of string interactions is formulated in terms of two-dimensional fermion fields and without boson fields commonly used in string theories. The vertex operators for emission of π-mesons are constructed within the framework of this approach. 5 refs

  10. Semilocal and electroweak strings

    NARCIS (Netherlands)

    Achucarro, A; Vachaspati, T

    We review a class of non-topological defects in the standard electroweak model, and their implications. Starting with the semilocal string, which provides a counterexample to many well-known properties of topological vortices, we discuss electroweak strings and their stability with and without

  11. Inflationary string theory?

    Indian Academy of Sciences (India)

    Furthermore, the success of this description indicates that inflation is likely to be associated with physics at energies considerably higher than the weak scale, for which string theory is arguably our most promising candidate. These observations strongly motivate a detailed search for inflation within string theory, although it ...

  12. Open string model building

    International Nuclear Information System (INIS)

    Ishibashi, Nobuyuki; Onogi, Tetsuya

    1989-01-01

    Consistency conditions of open string theories, which can be a powerful tool in open string model building, are proposed. By making use of these conditions and assuming a simple prescription for the Chan-Paton factors, open string theories in several backgrounds are studied. We show that 1. there exist a large number of consistent bosonic open string theories on Z 2 orbifolds, 2. SO(32) type I superstring is the unique consistent model among fermionic string theories on the ten-dimensional flat Minkowski space, and 3. with our prescription for the Chan-Paton factors, there exist no consistent open superstring theories on (six-dimensional Minkowski space-time) x (Z 2 orbifold). (orig.)

  13. String-Math 2015

    CERN Document Server

    2015-01-01

    Welcome to String-Math 2015 at Sanya. The conference will be opened in December 31, 2015- January 4, 2016. String theory plays a central role in theoretical physics as a candidate for the quantum theory unifying gravity with other interactions. It has profound connections with broad branches of modern mathematics ever since the birth. In the last decades, the prosperous interaction, built upon the joint efforts from both mathematicians and physicists, has given rise to marvelous deep results in supersymmetric gauge theory, topological string, M-theory and duality on the physics side as well as in algebraic geometry, differential geometry, algebraic topology, representation theory and number theory on the mathematics side. The interplay is two-fold. The mathematics has provided powerful tools to fulfill the physical interconnection of ideas and clarify physical structures to understand the nature of string theory. On the other hand, ideas from string theory and quantum field theory have been a source of sign...

  14. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  15. A cross-sectional study of psychosocial work environment and stress in the Danish symphony orchestras.

    Science.gov (United States)

    Holst, Gitte Juel; Paarup, Helene M; Baelum, Jesper

    2012-08-01

    To investigate psychosocial work environment and stress in Danish symphony orchestra musicians. This was a cross-sectional questionnaire survey of psychosocial work factors and stress symptoms among 441 musicians in six Danish symphony orchestras. The response rate was 78% (n = 342). The questions were from COPSOQ (Copenhagen Psychosocial Questionnaire). Mean values of 19 COPSOQ-scales were compared by gender and instrument group. The results for the musicians were compared with results for the general Danish work force (COPSOQ database). Female musicians reported higher work demands and higher stress symptoms than their male colleagues. Between instrument groups, 2nd violinists seemed to be of particular risk compared with the other instrumental groups in aspects of work pace, work organization, and content, whereas 1st violinists perceived higher emotional stress compared with 2nd violinists. The musicians' experience of increased work demands as well as deteriorated, work organization and job content, interpersonal relations and leadership, and work-individual interface was significantly associated with increasing stress symptoms. Compared to the general workforce independently of gender, Danish symphony orchestra musicians reported higher emotional demands, lower influence, lower social support, lower sense of community, and lower job satisfaction. However, the musicians reported a higher commitment to the workplace. The findings indicate a more demanding psychosocial work environment exposure among symphony orchestra musicians than among Danish workers in general. Critical results are the relatively high work demands, low influence, and low social support, females being of higher risk than males.

  16. DIGEST MATERIALS FOR IMPROVING AND EXTENDING THE JUNIOR HIGH SCHOOL ORCHESTRA REPERTORY. VOLUME 3, ROMANTIC.

    Science.gov (United States)

    MOORE, JUNE

    PREPARED AS PART OF "PROJECT IMPROVING AND EXTENDING THE JUNIOR HIGH SCHOOL ORCHESTRA REPERTORY," THIS VOLUME CONTAINS CURRICULAR MATERIALS REPRESENTING THE ROMANTIC PERIOD. A MUSICAL HISTORY OF THE PERIOD IS GIVEN, AS WELL AS HISTORIES OF THE COMPOSERS AND THEIR INDIVIDUAL COMPOSITIONS. THE MATERIALS ARE PREPARED FOR THREE DEGREES OF TECHNICAL…

  17. DIGEST MATERIALS FOR IMPROVING AND EXTENDING THE JUNIOR HIGH SCHOOL ORCHESTRA REPERTORY. VOLUME 2, CLASSICAL.

    Science.gov (United States)

    MOORE, JUNE

    PREPARED AS PART OF "PROJECT IMPROVING AND EXTENDING THE JUNIOR HIGH SCHOOL ORCHESTRA REPERTORY," THIS VOLUME CONTAINS CURRICULAR MATERIALS REPRESENTING THE CLASSICAL PERIOD. A HISTORY OF THE PERIOD IS GIVEN, AS WELL AS HISTORIES OF THE COMPOSERS AND THEIR INDIVIDUAL COMPOSITIONS. THE MATERIALS ARE PREPARED FOR FOUR DEGREES OF TECHNICAL…

  18. Bruckner: Simfonie N8 c-moll, London Philharmonic Orchestra, Neeme Järvi / Martin Elste

    Index Scriptorium Estoniae

    Elste, Martin

    1990-01-01

    Uuest heliplaadist "Bruckner: Simfonie N8 c-moll; Reger: Variationen und Fuge über ein Thema von Beethoven op. 86. London Philharmonic Orchestra, Neeme Järvi". Chandos/ Koch Records 2 CD 8843/44 (WD: 107'13") DDD

  19. The Effect of Three Orchestra/School Partnerships on Students' Interest in Instrumental Music Instruction

    Science.gov (United States)

    Abeles, Hal

    2004-01-01

    This study is an examination of the influence of three orchestra/school partnerships on students' interest in instrumental music. A vocational choice school was used to assess students' interest in instrumental music. Surveys were administered to second- through fourth-grade students at partnership and nonpartnership schools. Results indicated…

  20. Compromises in orchestra pit design: A ten-year trench war in The Royal Theatre, Copenhagen

    DEFF Research Database (Denmark)

    Gade, Anders Christian; Mortensen, Bo

    1998-01-01

    The ``old stage'' of The Royal Theatre in Copenhagen-a classical horseshoe theatre with an almost flat audience floor and four balcony levels—is the primary opera and ballet theatre in Denmark. In the early 1980s the orchestra pit was enlarged and its size made flexible. However, in the following...

  1. Noise induced hearing loss and other hearing complaints among musicians of symphony orchestras

    NARCIS (Netherlands)

    Jansen, E.J.M.; Helleman, H.W.; Dreschler, W.A.; de Laat, J.A.P.M.

    2009-01-01

    OBJECTIVES: An investigation of the hearing status of musicians of professional symphony orchestras. Main questions are: (1) Should musicians be treated as a special group with regard to hearing, noise, and noise related hearing problems (2) Do patterns of hearing damage differ for different

  2. So What's New? A Survey of the Educational Policies of Orchestras and Opera Companies

    Science.gov (United States)

    Winterson, Julia

    2010-01-01

    The creative music workshop involving professional players was intended to give direct support to school teachers and to enhance music in the classroom. However, today's large-scale, high-profile projects mounted by orchestras and opera companies appear to be developing into a full-scale industry on their own, their role in partnership with…

  3. Comparing the Impact of Specific Strength Training vs General Fitness Training on Professional Symphony Orchestra Musicians

    DEFF Research Database (Denmark)

    Nygaard Andersen, Lotte; Mann, Stephanie; Juul-Kristensen, Birgit

    2017-01-01

    mass index, and self-assessed physical fitness. A total of 23 professional symphony orchestra musicians were randomly allocated to either the SST (n=12) or GFT (n=11) groups. Participants conducted three 20-minutes exercise periods/wk at the workplace for 9 weeks. RESULTS: Evaluations of both...

  4. Empowering or Boring? Discipline and Authority in a Portuguese Sistema-Inspired Orchestra Rehearsal

    Science.gov (United States)

    Boia, Pedro S.; Boal-Palheiros, Graça

    2017-01-01

    El Sistema orchestras may be "transformative" and produce positive changes in the lives of young participants, but there are also negative aspects to discipline and authority that may lead to exclusion. This article positions itself within the current debate on Sistema by treating symmetrically its potentially positive and negative…

  5. String field theory

    International Nuclear Information System (INIS)

    Kaku, M.

    1987-01-01

    In this article, the authors summarize the rapid progress in constructing string field theory actions, such as the development of the covariant BRST theory. They also present the newer geometric formulation of string field theory, from which the BRST theory and the older light cone theory can be derived from first principles. This geometric formulation allows us to derive the complete field theory of strings from two geometric principles, in the same way that general relativity and Yang-Mills theory can be derived from two principles based on global and local symmetry. The geometric formalism therefore reduces string field theory to a problem of finding an invariant under a new local gauge group they call the universal string group (USG). Thus, string field theory is the gauge theory of the universal string group in much the same way that Yang-Mills theory is the gauge theory of SU(N). The geometric formulation places superstring theory on the same rigorous group theoretical level as general relativity and gauge theory

  6. Duality relation between charged elastic strings and superconducting cosmic strings

    International Nuclear Information System (INIS)

    Carter, B.

    1989-01-01

    The mechanical properties of macroscopic electromagnetically coupled string models in a flat or curved background are treated using a covariant formalism allowing the construction of a duality transformation that relates the category of uniform ''electric'' string models, constructed as the (nonconducting) charged generalisation of ordinary uncoupled (violin type) elastic strings, to a category of ''magnetic'' string models comprising recently discussed varieties of ''superconducting cosmic strings''. (orig.)

  7. Final Report: "Strings 2014"

    Energy Technology Data Exchange (ETDEWEB)

    Witten, Edward

    2015-10-21

    The Strings 2014 meeting was held at Princeton University June 23-27, 2014, co-sponsored by Princeton University and the Institute for Advanced Study. The goal of the meeting was to provide a stimulating and up-to-date overview of research in string theory and its relations to other areas of physics and mathematics, ranging from geometry to quantum field theory, condensed matter physics, and more. This brief report lists committee members and speakers but contains no scientific information. Note that the talks at Strings 2014 were videotaped and are available on the conference website: http://physics.princeton.edustrings2014/Talk_titles.shtml.

  8. String theory for pedestrians

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    In this 3-lecture series I will discuss the basics of string theory, some physical applications, and the outlook for the future. I will begin with the main concepts of the classical theory and the application to the study of cosmic superstrings. Then I will turn to the quantum theory and discuss applications to the investigation of hadronic spectra and the recently discovered quark-gluon plasma. I will conclude with a sketch of string models of particle physics and showing some avenues that may lead to a complete formulation of string theory.

  9. Superconducting cosmic strings

    International Nuclear Information System (INIS)

    Chudnovsky, E.M.; Field, G.B.; Spergel, D.N.; Vilenkin, A.

    1986-01-01

    Superconducting loops of string formed in the early Universe, if they are relatively light, can be an important source of relativistic particles in the Galaxy. They can be observed as sources of synchrotron radiation at centimeter wavelengths. We propose a string model for two recently discovered radio sources, the ''thread'' in the galactic center and the source G357.7-0.1, and predict that the filaments in these sources should move at relativistic speeds. We also consider superheavy superconducting strings, and the possibility that they be observed as extragalactic radio sources

  10. Classical Music at a German Inner-City School: The German Philharmonic Chamber Orchestra Bremen at Comprehensive School Bremen East

    Directory of Open Access Journals (Sweden)

    Anna-Lena Musiol

    2013-12-01

    Full Text Available The German Philharmonic Chamber Orchestra Bremen, a world famous orchestra for classical music, and the Comprehensive School Bremen East, a school in a deprived area, in North American terms an inner-city school, are cooperating since 2007. A three-year follow-up evaluation study was conducted to find out, if projects facilitated by the presence of the orchestra have a positive impact on the self-reported well-being and the grades of students. Results showed that involvement in the projects distinctly benefited boys: They experience a better class climate and a higher satisfaction with school as well as improved German grades.

  11. Cosmic strings and cosmic structure

    International Nuclear Information System (INIS)

    Albrecht, A.; Brandenberger, R.; Turok, N.

    1987-01-01

    The paper concerns the application of the theory of cosmic strings to explain the structure of the Universe. The formation of cosmic strings in the early Universe is outlined, along with the Big Bang theory, Grand Unified theories, and the first three minutes after the Big Bang. A description is given of the shaping of the Universe by cosmic strings, including the evolution of the string. The possibility for direct observation of cosmic strings is discussed. (U.K.)

  12. International conference on string theory

    CERN Document Server

    2017-01-01

    The Strings 2017 conference is part of the "Strings" series of annual conferences, that bring the entire string theory community together. It will include reviews of major developments in the field, and specialized talks on specific topics. There will also be several public lectures given by conference participants, a pre-Strings school at the Technion, and a post-Strings workshop at the Weizmann Institute.

  13. Subsurface drill string

    Science.gov (United States)

    Casper, William L [Rigby, ID; Clark, Don T [Idaho Falls, ID; Grover, Blair K [Idaho Falls, ID; Mathewson, Rodney O [Idaho Falls, ID; Seymour, Craig A [Idaho Falls, ID

    2008-10-07

    A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

  14. Field theory of strings

    International Nuclear Information System (INIS)

    Ramond, P.

    1987-01-01

    We review the construction of the free equations of motion for open and closed strings in 26 dimensions, using the methods of the Florida Group. Differing from previous treatments, we argue that the constraint L 0 -anti L 0 =0 should not be imposed on all the fields of the closed string in the gauge invariant formalism; we show that it can be incorporated in the gauge invariant formalism at the price of being unable to extract the equations of motion from a Langrangian. We then describe our purely algebraic method to introduce interactions, which works equally well for open and closed strings. Quartic interactions are absent except in the Physical Gauge. Finally, we speculate on the role of the measure of the open string path functional. (orig.)

  15. The QCD Effective String

    International Nuclear Information System (INIS)

    Espriu, D.

    2003-01-01

    QCD can be described in a certain kinematical regime by an effective string theory. This string must couple to background chiral fields in a chirally invariant manner, thus taking into account the true chirally non-invariant QCD vacuum. By requiring conformal symmetry of the string and the unitarity constraint on chiral fields we reconstruct the equations of motion for the latter ones. These provide a consistent background for the propagation of the string. By further requiring locality of the effective action we recover the Lagrangian of non-linear sigma model of pion interactions. The prediction is unambiguous and parameter-free. The estimated chiral structural constants of Gasser and Leutwyler fit very well the phenomenological values. (author)

  16. Strings with zero tension

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, R.; Barcelos-Neto, J.

    1988-05-01

    We describe bosonic strings by using a kind of Lagrangian compatible with the zero tension limit. The work is developed on an extended configuration space and the quantization is carried out with details.

  17. Field theory of strings

    International Nuclear Information System (INIS)

    Ramond, P.

    1986-01-01

    We review the construction of the free equations of motion for open and closed strings in 26 dimensions, using the methods of the Florida Group. Differing from previous treatments, we argue that the constraint L 0 - L 0 -bar = 0 should not be imposed on all the fields of the closed string in the gauge invariant formalism: we show that it can be incorporated in the invariant formalism at the price of being unable to extract the equations of motion from a Lagrangian. We then describe our purely algebraic method to introduce interactions, which works equally well for open and closed strings. Quartic interactions are absent except in the Physical Gauge. Finally, we speculate on the role of the measure of the open string path functional. 20 refs

  18. String Theory Rocks!

    CERN Multimedia

    2008-01-01

    String Theory supporters argue that the universe we live in has eleven dimensions, out of which three spacial dimensions and a temporal one, which define the void and the space-time environment we experience daily.

  19. String theory compactifications

    CERN Document Server

    Graña, Mariana

    2017-01-01

    The lectures in this book provide graduate students and non-specialist researchers with a concise introduction to the concepts and formalism required to reduce the ten-dimensional string theories to the observable four-dimensional space-time - a procedure called string compactification. The text starts with a very brief introduction to string theory, first working out its massless spectrum and showing how the condition on the number of dimensions arises. It then dwells on the different possible internal manifolds, from the simplest to the most relevant phenomenologically, thereby showing that the most elegant description is through an extension of ordinary Riemannian geometry termed generalized geometry, which was first introduced by Hitchin. Last but not least, the authors review open problems in string phenomenology, such as the embedding of the Standard Model and obtaining de Sitter solutions.

  20. Selected Physical Characteristics and Playing-Related Musculoskeletal Problems in Adolescent String Instrumentalists.

    Science.gov (United States)

    Vinci, Stefano; Smith, Anne; Ranelli, Sonia

    2015-09-01

    Music research has investigated the prevalence of playing-related musculoskeletal problems in adults and children, but the prevalence in adolescents has not been established. String instrumentalists report high problem rates, though it is unclear whether rates vary between upper and lower strings in adolescent instrumentalists. Further, there is limited evidence for the association between physical characteristics and playing problems in this group of musicians. Seventy-six adolescent string musicians from the West Australian Youth Orchestras were surveyed. Their experience of playing problems, both symptoms (PRMS) and disorders (PRMD), within the last month and measurements of body mass index, hand span, and joint mobility (Beighton scale) were obtained. Prevalence rates were calculated and compared between upper and lower string instrumentalists using a chi-squared test. Logistic regression examined the association of physical measures with playing problems, adjusting for confounding factors. Within the last month, 73.5% participants reported experiencing a PRMS and 26.5percnt; reported experiencing a PRMD. There was no significant difference between the problem rates in upper and lower string instrumentalists. After adjusting for potential confounders, an increasing count of hypermobile joints remained significantly associated with problems (OR 1.76, CI 1.02 to 3.04, p=0.042). This study found playing problems are common in adolescent string instrumentalists, though rates did not differ between upper and lower string players. Joint hypermobility was associated with playing-related problems in adolescent musicians. Early identification of problems in this group of maturing musicians may help prevent disabling disorders and maximize performance.

  1. Manipulating Strings in Python

    Directory of Open Access Journals (Sweden)

    William J. Turkel

    2012-07-01

    Full Text Available This lesson is a brief introduction to string manipulation techniques in Python. Knowing how to manipulate strings plays a crucial role in most text processing tasks. If you’d like to experiment with the following lessons, you can write and execute short programs as we’ve been doing, or you can open up a Python shell / Terminal to try them out on the command line.

  2. String dynamics in QCD

    International Nuclear Information System (INIS)

    Gervais, J.L.; Neveu, A.

    1980-01-01

    Recent works of the authors on string interpretation of the Wilson loop operators in QCD are reviewed in a self-contained fashion. Although most of the results habe already appeared in print, some new material is presented in renormalization of the Wilson loop operator and on the use of light-cone expansion to derive a linear string-like equation in light-cone formalism. (orig.)

  3. String scattering amplitudes and deformed cubic string field theory

    Directory of Open Access Journals (Sweden)

    Sheng-Hong Lai

    2018-01-01

    Full Text Available We study string scattering amplitudes by using the deformed cubic string field theory which is equivalent to the string field theory in the proper-time gauge. The four-string scattering amplitudes with three tachyons and an arbitrary string state are calculated. The string field theory yields the string scattering amplitudes evaluated on the world sheet of string scattering whereas the conventional method, based on the first quantized theory brings us the string scattering amplitudes defined on the upper half plane. For the highest spin states, generated by the primary operators, both calculations are in perfect agreement. In this case, the string scattering amplitudes are invariant under the conformal transformation, which maps the string world sheet onto the upper half plane. If the external string states are general massive states, generated by non-primary field operators, we need to take into account carefully the conformal transformation between the world sheet and the upper half plane. We show by an explicit calculation that the string scattering amplitudes calculated by using the deformed cubic string field theory transform into those of the first quantized theory on the upper half plane by the conformal transformation, generated by the Schwarz–Christoffel mapping.

  4. CONTEMPORARY APPROACH TO THE CAROL IN THE WORK FOR STRING ORCHESTRA THE CHRISTMAS NIGHT BY V. CIOLAC

    Directory of Open Access Journals (Sweden)

    ECATERINA GÎRBU

    2017-06-01

    Full Text Available In the article there is an integral analysis of the orchestral composition Christmas Night written by Vladimir Ciolac. Over the centuries, the historical event linked to the Birth of the Savior finds an extremely varied and diverse reflection in universal musical art. This subject is represented by a very broad genre diversity, being approached in both church music and secular music. The name of the piece reveals the content of the paper and suggests that it is an original carol. The composer uses the theme of the Birth of the Savior — an event of major significance in the life of mankind, creating a contemporary carol from the point of view of the treatment of the musical discourse.

  5. Is Playing in the Pit Really the Pits?: Pain, Strength, Music Performance Anxiety, and Workplace Satisfaction in Professional Musicians in Stage, Pit, and Combined Stage/Pit Orchestras.

    Science.gov (United States)

    Kenny, Dianna T; Driscoll, Tim; Ackermann, Bronwen J

    2016-03-01

    Typically, Australian orchestral musicians perform on stage, in an orchestra pit, or in a combination of both workplaces. This study explored a range of physical and mental health indicators in musicians who played in these different orchestra types to ascertain whether orchestra environment was a risk factor affecting musician wellbeing. Participants comprised 380 full-time orchestral musicians from the eight major state orchestras in Australia comprised of two dedicated pit orchestras, three stage-only symphonic orchestras, and three mixed stage/pit orchestras. Participants completed a physical assessment and a range of self-report measures assessing performance-related musculoskeletal disorders (PRMD), physical characteristics including strength and perceived exertion, and psychological health, including music performance anxiety (MPA), workplace satisfaction, and bullying. Physical characteristics and performance-related musculoskeletal profiles were similar for most factors on the detailed survey completed by orchestra members. The exceptions were that pit musicians demonstrated greater shoulder and elbow strength, while mixed-workload orchestra musicians had greater flexibility Significantly more exertion was reported by pit musicians when rehearsing and performing. Stage/pit musicians reported less physical exertion when performing in the pit compared with performing on stage. Severity of MPA was significantly greater in pit musicians than mixed orchestra musicians. Pit musicians also reported more frequent bullying and lower job satisfaction compared with stage musicians. There were few differences in the objective physical measures between musicians in the different orchestra types. However, pit musicians appear more psychologically vulnerable and less satisfied with their work than musicians from the other two orchestra types. The physical and psychological characteristics of musicians who perform in different orchestra types have not been adequately

  6. Strings, Axions and Solitons.

    Science.gov (United States)

    Dabholkar, Atish

    This thesis is divided into two chapters. Chapter I is about the dynamics of radiating axionic strings and the lower bound on the mass of the invisible axion. It has been suggested that, without inflation, the decay of axionic strings produced after the Peccei -Quinn phase transition is the primary source of cosmic relic axions. Knowing the density of these axions would then allow the derivation of a cosmological bound on the mass of the axion. In order to obtain a sharp bound it is essential to know the spectrum of the emitted axions and the detailed motion of a global string strongly coupled to the axionic field. To this end, following the analogy with Dirac's treatment of classical radiating electrons, self-consistent renormalized equations are obtained that describe the dynamics of a radiating global string interacting with its surrounding axionic field. The numerical formalism for evolving string trajectories using these equations is described, and is applied to the case of a circular loop. It is argued that for large wavelength oscillations of cosmic string loops, the motion is well approximated by the motion of a free Nambu-Goto string with appropriate renormalization. Consequently, a lower bound of 10 ^{-3} eV on the mass of the axion is obtained. Together with the recent upperbound of 4 times 10^{-4 } eV from the supernova SN1987a, it marginally rules out the invisible axion. Chapter II is about superstrings and solitons. It is shown that the quantum renormalization of the superstring tension vanishes to all orders in string perturbation theory. A low-energy analysis of macroscopic superstrings is presented and various analogies between these superstrings and solitons in supersymmetric theories are discussed. These include the existence of exact multi-string solutions of the low -energy supergravity super-Yang-Mills equations of motion and a Bogomol'nyi bound for the energy per unit length which is saturated by these solutions. Arguments are presented that

  7. New Developments in String Gravity and String Cosmology.A Summary Report

    OpenAIRE

    Sanchez, Norma G.

    2002-01-01

    New Developments in String Gravity and String Cosmology are reported: 1-String driven cosmology and its Predictions. 2-The primordial gravitational wave background in string cosmology. 3-Non-singular string cosmologies from Exact Conformal Field Theories. 4-Quantum Field Theory, String Temperature and the String Phase of de Sitter space-time, 5-Hawking Radiation in String Theory and the String Phase of Black Holes. 6-New Dual Relation between Quantum Field Theory regimes and String regimes in...

  8. Prom Health and Safety Tips

    Science.gov (United States)

    ... Autumn Tips Camping Tips Family Reunions Gardening Tips Halloween Tips Healthy Halloween Prom Tips Spring Break Valentine Tips Winter Holiday ... Breast Cancer Assess Your Relationships Be Safe on Halloween Be Smoke-Free Check Alarm Batteries Know Your ...

  9. Investigations of Orchestra Auralizations Using the Multi-Channel Multi-Source Auralization Technique

    DEFF Research Database (Denmark)

    Vigeant, Michelle; Wang, Lily M.; Rindel, Jens Holger

    2008-01-01

    a multi-channel multi-source auralization technique, involving individual five-channel anechoic recordings of each instrumental part of two symphonies. In the first study, these auralizations were subjectively compared to orchestra auralizations made using (a) a single omni-directional source, (b......) a surface source, and (c) single-channel multi-source method. Results show that the multi-source auralizations were rated to be more realistic than the surface source ones and to have larger source width than the single omni-directional source auralizations. No significant differences were found between......Room acoustics computer modeling is a tool for generating impulse responses and auralizations from modeled spaces. The auralizations are commonly made from a single-channel anechoic recording of solo instruments. For this investigation, auralizations of an entire orchestra were created using...

  10. PT-symmetric strings

    International Nuclear Information System (INIS)

    Amore, Paolo; Fernández, Francisco M.; Garcia, Javier; Gutierrez, German

    2014-01-01

    We study both analytically and numerically the spectrum of inhomogeneous strings with PT-symmetric density. We discuss an exactly solvable model of PT-symmetric string which is isospectral to the uniform string; for more general strings, we calculate exactly the sum rules Z(p)≡∑ n=1 ∞ 1/E n p , with p=1,2,… and find explicit expressions which can be used to obtain bounds on the lowest eigenvalue. A detailed numerical calculation is carried out for two non-solvable models depending on a parameter, obtaining precise estimates of the critical values where pair of real eigenvalues become complex. -- Highlights: •PT-symmetric Hamiltonians exhibit real eigenvalues when PT symmetry is unbroken. •We study PT-symmetric strings with complex density. •They exhibit regions of unbroken PT symmetry. •We calculate the critical parameters at the boundaries of those regions. •There are exact real sum rules for some particular complex densities

  11. Windings of twisted strings

    Science.gov (United States)

    Casali, Eduardo; Tourkine, Piotr

    2018-03-01

    Twistor string models have been known for more than a decade now but have come back under the spotlight recently with the advent of the scattering equation formalism which has greatly generalized the scope of these models. A striking ubiquitous feature of these models has always been that, contrary to usual string theory, they do not admit vibrational modes and thus describe only conventional field theory. In this paper we report on the surprising discovery of a whole new sector of one of these theories which we call "twisted strings," when spacetime has compact directions. We find that the spectrum is enhanced from a finite number of states to an infinite number of interacting higher spin massive states. We describe both bosonic and world sheet supersymmetric models, their spectra and scattering amplitudes. These models have distinctive features of both string and field theory, for example they are invariant under stringy T-duality but have the high energy behavior typical of field theory. Therefore they describe a new kind of field theories in target space, sitting on their own halfway between string and field theory.

  12. Perspectives on string phenomenology

    CERN Document Server

    Kane, Gordon; Kumar, Piyush

    2015-01-01

    The remarkable recent discovery of the Higgs boson at the CERN Large Hadron Collider completed the Standard Model of particle physics and has paved the way for understanding the physics which may lie beyond it. String/M theory has emerged as a broad framework for describing a plethora of diverse physical systems, which includes condensed matter systems, gravitational systems as well as elementary particle physics interactions. If string/M theory is to be considered as a candidate theory of Nature, it must contain an effectively four-dimensional universe among its solutions that is indistinguishable from our own. In these solutions, the extra dimensions of string/M Theory are “compactified” on tiny scales which are often comparable to the Planck length. String phenomenology is the branch of string/M theory that studies such solutions, relates their properties to data, and aims to answer many of the outstanding questions of particle physics beyond the Standard Model. This book contains perspectives on stri...

  13. Orchestra of Change: Strategically Harmonizing National Character, Military Forces, and the Character of War

    Science.gov (United States)

    2015-06-01

    89 Jason Healey , ed., A Fierce Domain : Conflict in Cyberspace, 1986 to 2012 (Washington, DC: Atlantic Council, 2013), 70–72. 90... A Fierce Domain : Conflict in Cyberspace, 1986 to 2012. Washington, DC: Atlantic Council, 2013. Hoffman, David E. The Dead Hand: The Untold Story...ORCHESTRA OF CHANGE: STRATEGICALLY HARMONIZING NATIONAL CHARACTER, MILITARY FORCES, AND THE CHARACTER OF WAR BY SCOTT GUNN A THESIS

  14. String field theory solution for any open string background

    Czech Academy of Sciences Publication Activity Database

    Erler, T.; Maccaferri, Carlo

    2014-01-01

    Roč. 10, Oct (2014), 1-37 ISSN 1029-8479 R&D Projects: GA ČR GBP201/12/G028 Institutional support: RVO:68378271 Keywords : tachyon condensation * string field theory * conformal field models in string theory * bosonic strings Subject RIV: BE - Theoretical Physics Impact factor: 6.111, year: 2014

  15. Interacting-string picture of the fermionic string

    International Nuclear Information System (INIS)

    Mandelstam, S.

    1986-01-01

    This report gives a review of the interacting-string picture of the Bose string. In the present lecture, the author outlines a similar treatment of the Fermionic string. The quantization of the free Fermionic string is carried out to the degrees of freedom x, representing the displacement of the string. Also presented are Grassman degrees of freedom S distributed along the string. The report pictures the fermionic string as a string of dipoles. The general picture of the interaction of such strings by joining and splitting is the same as for the Bose string. The author does not at present have the simplest formula for fermion string scattering amplitudes. A less detailed treatment is given than for the Bose string. The report sets up the functional-integration formalism, derives the analog mode, and indicates in general, terms how the conformal transformation to the z-plane may be performed. The paper concludes by stating without proof the formula for the N-article tree amplitude in the manifestly supersymmetric formalism

  16. Tips for Daily Living

    Science.gov (United States)

    ... Tips and Gadgets for Daily Activities Dressing Tips Shopping Tips Modifying the Bathroom Driving After Stroke Medication ... and resources. Find a group in your area . Online Support If there is not a support group ...

  17. The confining trailing string

    CERN Document Server

    Kiritsis, E; Nitti, F

    2014-01-01

    We extend the holographic trailing string picture of a heavy quark to the case of a bulk geometry dual to a confining gauge theory. We compute the classical trailing confining string solution for a static as well as a uniformly moving quark. The trailing string is infinitely extended and approaches a confining horizon, situated at a critical value of the radial coordinate, along one of the space-time directions, breaking boundary rotational invariance. We compute the equations for the fluctuations around the classical solutions, which are used to obtain boundary force correlators controlling the Langevin dynamics of the quark. The imaginary part of the correlators has a non-trivial low-frequency limit, which gives rise to a viscous friction coefficient induced by the confining vacuum. The vacuum correlators are used to define finite-temperature dressed Langevin correlators with an appropriate high-frequency behavior.

  18. Strings for quantumchromodynamics

    International Nuclear Information System (INIS)

    Schomerus, V.

    2007-04-01

    During the last decade, intriguing dualities between gauge and string theory have been found and explored. they provide a novel window on strongly couplde gauge physics, including QCD-like models. Based on a short historical review of modern string theory, we explain how so-called AdS/CFT dualities emerged at the end of the 1990s. Some of their concrete implications and remarkable recent progress are then illustrated for the simplest example, namely the multicolor limit of N=4 SYM theory in four dimensions. We end with a few comments on existing extensions to more realistic models and applications, in particular to the sQGP. This text is meant as a non-technical introduction to gauge/string dualities for (particle) physicists. (orig.)

  19. The confining trailing string

    Energy Technology Data Exchange (ETDEWEB)

    Kiritsis, Elias [APC, Université Paris 7, CNRS/IN2P3, CEA/IRFU, Obs. de Paris, Sorbonne Paris Cité,Bâtiment Condorcet, F-75205, Paris Cedex 13 (UMR du CNRS 7164) (France); Theory Group, Physics Department, CERN,CH-1211, Geneva 23 (Switzerland); Crete Center for Theoretical Physics, Department of Physics, University of Crete,71003 Heraklion (Greece); Mazzanti, Liuba [Institute for Theoretical Physics and Spinoza Institute, Utrecht University,3508 TD Utrecht (Netherlands); Nitti, Francesco [APC, Université Paris 7, CNRS/IN2P3, CEA/IRFU, Obs. de Paris, Sorbonne Paris Cité,Bâtiment Condorcet, F-75205, Paris Cedex 13 (UMR du CNRS 7164) (France)

    2014-02-19

    We extend the holographic trailing string picture of a heavy quark to the case of a bulk geometry dual to a confining gauge theory. We compute the classical trailing confining string solution for a static as well as a uniformly moving quark. The trailing string is infinitely extended and approaches a confining horizon, situated at a critical value of the radial coordinate, along one of the space-time directions, breaking boundary rotational invariance. We compute the equations for the fluctuations around the classical solutions, which are used to obtain boundary force correlators controlling the Langevin dynamics of the quark. The imaginary part of the correlators has a non-trivial low-frequency limit, which gives rise to a viscous friction coefficient induced by the confining vacuum. The vacuum correlators are used to define finite-temperature dressed Langevin correlators with an appropriate high-frequency behavior.

  20. String theory meets QCD

    CERN Document Server

    Evans, N

    2003-01-01

    String theory began life in the late 1960s as an attempt to understand the properties of nuclear matter such as protons and neutrons. Although it was not successful it has since developed a life of its own as a possible theory of everything - with the potential to incorporate quantum gravity as well as the other forces of nature. However, in a remarkable about face in the last five years, it has now been discovered that string theory and the standard theory of nuclear matter - QCD - might in fact describe the same physics. This is an exciting development that was the centre of discussion at a major workshop in Seattle in February. After spending 30 years as a possible theory of everything, string theory is returning to its roots to describe the interactions of quarks and gluons. (U.K.)

  1. Deriving the four-string and open-closed string interactions from geometric string field theory

    International Nuclear Information System (INIS)

    Kaku, M.

    1990-01-01

    One of the questions concerning the covariant open string field theory is why there are two distinct BRST theories and why the four-string interaction appears in one version but not the other. The authors solve this mystery by showing that both theories are gauge-fixed versions of a higher gauge theory, called the geometric string field theory, with a new field, a string verbein e μσ νρ , which allows us to gauge the string length and σ parametrization. By fixing the gauge, the authors can derive the endpoint gauge (the covariantized light cone gauge), the midpoint gauge of Witten, or the interpolating gauge with arbitrary string length. The authors show explicitly that the four-string interaction is a gauge artifact of the geometric theory (the counterpart of the four-fermion instantaneous Coulomb term of QED). By choosing the interpolating gauge, they produce a new class of four-string interactions which smoothly interpolate between the endpoint gauge and the midpoint gauge (where it vanishes). Similarly, they can extract the closed string as a bound state of the open string, which appears in the endpoint gauge but vanishes in the midpoint gauge. Thus, the four-string and open-closed string interactions do not have to be added to the action as long as the string vierbein is included

  2. Instability of colliding metastable strings

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Takashi [Kyoto Univ. (Japan). Yukawa Inst. for Theoretical Physics; Eto, Minoru [Yamagata Univ. (Japan). Dept. of Physics; Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research

    2013-04-15

    We investigate the collision dynamics of two metastable strings which can be viewed as tube-like domain walls with winding numbers interpolating a false vacuum and a true vacuum. We find that depending on the relative angle and speed of two strings, instability of strings increases and the false vacuum is filled out by rapid expansion of the strings or of a remnant of the collision.

  3. String theory in four dimensions

    International Nuclear Information System (INIS)

    Dine, M.

    1988-01-01

    A representative sample of current ideas about how one might develop a string phenomenology is presented. Some of the obstacles which lie in between string theory and contact with experiment are described. It is hoped that this volume will provide the reader with ways of thinking about string theory in four dimensions and provide tools for asking questions about string theory and ordinary physics. 102 refs

  4. Strings draw theorists together

    International Nuclear Information System (INIS)

    Green, Michael

    2000-01-01

    Theorists are confident that they are closer than ever to finding a quantum theory that unites gravity with the three other fundamental forces in nature. Many of the leading figures in the world of string theory met at the California Institute of Technology in January to discuss recent progress in the field and to reflect on the state of the theory. The enthusiastic mood of the gathering was based on the fact that string theory provides an elegant framework for a unified theory of all the forces and particles in nature, and also gives a consistent quantum-mechanical description of general relativity. String theory, and more precisely superstring theory, describes the assortment of elementary particles such as quarks and leptons, and the gauge bosons responsible for mediating forces in a unified manner as different modes of vibration of a single extended string. This version of the theory also embodies supersymmetry a conjectured symmetry that unifies fermions and bosons. Furthermore, the fact that the string has a fundamental length scale - the ''string length'' - apparently cures the short-distance problems of uniting general relativity with quantum theory. The main problem with the early formulations of superstring theory was that they emphasized the ''perturbative'' point of view, an approximation that describes string-like quantum-mechanical particles moving through classical (that is non quantum-mechanical) space-time. However, very general arguments require that any quantum theory of gravity should also describe space-time geometry in a quantum-mechanical manner. The classical geometry of space-time should then emerge as an approximate description at distance scales much larger than the so-called Planck scale of 10 -33 m. This requires an understanding of the theory beyond the perturbative approximation. It is the quest for this more fundamental description of string theory that has provided the main challenge for string theorists over the past decade. Much

  5. Matrix string partition function

    CERN Document Server

    Kostov, Ivan K; Kostov, Ivan K.; Vanhove, Pierre

    1998-01-01

    We evaluate quasiclassically the Ramond partition function of Euclidean D=10 U(N) super Yang-Mills theory reduced to a two-dimensional torus. The result can be interpreted in terms of free strings wrapping the space-time torus, as expected from the point of view of Matrix string theory. We demonstrate that, when extrapolated to the ultraviolet limit (small area of the torus), the quasiclassical expressions reproduce exactly the recently obtained expression for the partition of the completely reduced SYM theory, including the overall numerical factor. This is an evidence that our quasiclassical calculation might be exact.

  6. Cover array string reconstruction

    OpenAIRE

    Crochemore, Maxime; S. Iliopoulos, Costas; P. Pissis, Solon; Tischler, German

    2010-01-01

    International audience; A proper factor u of a string y is a cover of y if every letter of y is within some occurrence of u in y. The concept generalises the notion of periods of a string. An integer array C is the minimal-cover (resp. maximal-cover) array of y if C[i] is the minimal (resp. maximal) length of covers of y[0.. i], or zero if no cover exists. In this paper, we present a constructive algorithm checking the validity of an array as a minimal-cover or maximal-cover array of some str...

  7. A Prospective Evaluation of Duplex Ultrasound for Thoracic Outlet Syndrome in High-Performance Musicians Playing Bowed String Instruments

    Science.gov (United States)

    Adam, Garret; Wang, Kevin; Demaree, Christopher J; Jiang, Jenny S; Cheung, Mathew; Bechara, Carlos F; Lin, Peter H

    2018-01-25

    Thoracic outlet syndrome (TOS) is a neurovascular condition involving the upper extremity, which is known to occur in individuals who perform chronic repetitive upper extremity activities. We prospectively evaluate the incidence of TOS in high-performance musicians who played bowed string musicians. Sixty-four high-performance string instrument musicians from orchestras and professional musical bands were included in the study. Fifty-two healthy volunteers formed an age-matched control group. Bilateral upper extremity duplex scanning for subclavian vessel compression was performed in all subjects. Provocative maneuvers including Elevated Arm Stress Test (EAST) and Upper Limb Tension Test (ULTT) were performed. Abnormal ultrasound finding is defined by greater than 50% subclavian vessel compression with arm abduction, diminished venous waveforms, or arterial photoplethysmography (PPG) tracing with arm abduction. Bowed string instruments performed by musicians in our study included violin (41%), viola (33%), and cello (27%). Positive EAST or ULTT test in the musician group and control group were 44%, and 3%, respectively ( p = 0.03). Abnormal ultrasound scan with vascular compression was detected in 69% of musicians, in contrast to 15% of control subjects ( p = 0.03). TOS is a common phenomenon among high-performance bowed string instrumentalists. Musicians who perform bowed string instruments should be aware of this condition and its associated musculoskeletal symptoms.

  8. String theory in four dimensions

    CERN Document Server

    1988-01-01

    ``String Theory in Four Dimensions'' contains a representative collection of papers dealing with various aspects of string phenomenology, including compactifications on smooth manifolds and more general conformal field theories. Together with the lucid introduction by M. Dine, this material gives the reader a good working knowledge of our present ideas for connecting string theory to nature.

  9. Why Strings? Grand Masters Series.

    Science.gov (United States)

    Klotman, Robert H.

    2000-01-01

    Discusses the reasons to teach stringed instruments: (1) strings can be adapted to the size of the child; (2) home performance material resource availability; (3) stringed music skills contribute to developing basic skills; and (4) the importance of interaction in music. (CMK)

  10. A Vibrating String Experiment

    Science.gov (United States)

    Tsutsumanova, Gichka; Russev, Stoyan

    2013-01-01

    A simple experiment demonstrating the excitation of a standing wave in a metal string is presented here. Several tasks using the set-up are considered, which help the students to better understand the standing waves, the interaction between electric current and magnetic field and the resonance phenomena. This can serve also as a good lecture…

  11. New Z3 strings

    Directory of Open Access Journals (Sweden)

    Marco A.C. Kneipp

    2016-12-01

    Full Text Available We consider a Yang–Mills–Higgs theory with the gauge group SU(3 broken to its center Z3 by two scalar fields in the adjoint representation and obtain new Z3 strings asymptotic configurations with the gauge field and magnetic field in the direction of the step operators.

  12. On exceptional instanton strings

    NARCIS (Netherlands)

    Del Zotto, M.; Lockhart, G.

    According to a recent classification of 6d (1, 0) theories within F-theory there are only six “pure” 6d gauge theories which have a UV superconformal fixed point. The corresponding gauge groups are SU(3), SO(8), F4, E6, E7, and E8. These exceptional models have BPS strings which are also instantons

  13. Hypermultiplets and topological strings

    NARCIS (Netherlands)

    Rocek, M.; Vafa, C.; Vandoren, S.

    2005-01-01

    The c-map relates classical hypermultiplet moduli spaces in compactifications of type II strings on a Calabi-Yau threefold to vector multiplet moduli spaces via a further compactification on a circle. We give an off-shell description of the c-map in N = 2 superspace. The superspace Lagrangian for

  14. SUPERCOLLIDER: String test success

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    On 14 August at the Superconducting Supercollider (SSC) Laboratory in Ellis County, Texas, the Accelerator Systems String Test (ASST) successfully met its objective by operating a half-cell of five collider dipole magnets, one quadrupole magnet, and two spool pieces at the design current of 6500 amperes

  15. Disordered chaotic strings

    DEFF Research Database (Denmark)

    Schäfer, Mirko; Greiner, Martin

    Chaotic strings are coupled Tchebyscheff maps on a ring-network. With a well-specified empirical prescription they are able to explain the coupling constants of the standard model of elementary particle physics. This empirical relationship is tested further by introducing a tunable disorder to ch...

  16. Disordered chaotic strings

    DEFF Research Database (Denmark)

    Schäfer, Mirko; Greiner, Martin

    2011-01-01

    Chaotic strings are coupled Tchebyscheff maps on a ring-network. With a well-specified empirical prescription they are able to explain the coupling constants of the standard model of elementary particle physics. This empirical relationship is tested further by introducing a tunable disorder to ch...

  17. Help from the strings

    CERN Multimedia

    2007-01-01

    "How can the nature of basic particles be defined beyond the mechanisms presiding over their creation? Besides the standard model of particle physics - resulting from the postulations of quantum mechanics - contemporary science has pinned its hopes on the totally new unifying notion provided by the highly mathematical string theory."(2 pages)

  18. On exceptional instanton strings

    Science.gov (United States)

    Del Zotto, Michele; Lockhart, Guglielmo

    2017-09-01

    According to a recent classification of 6d (1 , 0) theories within F-theory there are only six "pure" 6d gauge theories which have a UV superconformal fixed point. The corresponding gauge groups are SU(3) , SO(8) , F 4 , E 6 , E 7, and E 8. These exceptional models have BPS strings which are also instantons for the corresponding gauge groups. For G simply-laced, we determine the 2d N=(0,4) worldsheet theories of such BPS instanton strings by a simple geometric engineering argument. These are given by a twisted S 2 compactification of the 4d N=2 theories of type H 2 , D 4 , E 6 , E 7 and E 8 (and their higher rank generalizations), where the 6d instanton number is mapped to the rank of the corresponding 4d SCFT. This determines their anomaly polynomials and, via topological strings, establishes an interesting relation among the corresponding T 2 × S 2 partition functions and the Hilbert series for moduli spaces of G instantons. Such relations allow to bootstrap the corresponding elliptic genera by modularity. As an example of such procedure, the elliptic genera for a single instanton string are determined. The same method also fixes the elliptic genus for case of one F 4 instanton. These results unveil a rather surprising relation with the Schur index of the corresponding 4d N=2 models.

  19. Lectures on strings and dualities

    International Nuclear Information System (INIS)

    Vafa, C.

    1997-01-01

    In this set of lectures I review recent developments in string theory emphasizing their non-perturbative aspects and their recently discovered duality symmetries. The goal of the lectures is to make the recent exciting developments in string theory accessible to those with no previous background in string theory who wish to join the research effort in this area. Topics covered include a brief review of string theory, its compactifications, solitons and D-branes, black hole entropy and wed of string dualities. (author)

  20. Device for balancing parallel strings

    Science.gov (United States)

    Mashikian, Matthew S.

    1985-01-01

    A battery plant is described which features magnetic circuit means in association with each of the battery strings in the battery plant for balancing the electrical current flow through the battery strings by equalizing the voltage across each of the battery strings. Each of the magnetic circuit means generally comprises means for sensing the electrical current flow through one of the battery strings, and a saturable reactor having a main winding connected electrically in series with the battery string, a bias winding connected to a source of alternating current and a control winding connected to a variable source of direct current controlled by the sensing means. Each of the battery strings is formed by a plurality of batteries connected electrically in series, and these battery strings are connected electrically in parallel across common bus conductors.

  1. Gravitational effects of global strings

    International Nuclear Information System (INIS)

    Aryal, M.; Everett, A.E.

    1986-01-01

    We have obtained the gravitational field, in the weak-field approximation, of cosmic strings formed in a phase transition in which a global symmetry is broken (global strings). The effect of this field on light rays passing a global string is found, and the resulting formation of double images and production of discontinuities in the microwave background temperature compared with the corresponding results for gauge strings. There are some differences in the case of global strings, reflecting the fact that the space surrounding such strings is not purely conical. However, the differences between gauge and global strings with masses suitable to explain galaxy formation are small, and the task of distinguishing them observationally appears difficult at best

  2. Stringing physics along

    Energy Technology Data Exchange (ETDEWEB)

    Riordan, M. [Stanford University and the University of California, Santa Cruz (United States)]. E-mail: mriordan@ucsc.edu

    2007-02-15

    In the last few decades, however, physical theory has drifted away from the professional norms advocated by Newton and other enlightenment philosophers. A vast outpouring of hypotheses has occurred under the umbrella of what is widely called string theory. But string theory is not really a 'theory' at all - at least not in the strict sense that scientists generally use the term. It is instead a dense, weedy thicket of hypotheses and conjectures badly in need of pruning. That pruning, however, can come only from observation and experiment, to which string theory (a phrase I will grudgingly continue using) is largely inaccessible. String theory was invented in the 1970s in the wake of the Standard Model of particle physics. Encouraged by the success of gauge theories of the strong, weak and electromagnetic forces, theorists tried to extend similar ideas to energy and distance scales that are orders of magnitude beyond what can be readily observed or measured. The normal, healthy intercourse between theory and experiment - which had led to the Standard Model - has broken down, and fundamental physics now finds itself in a state of crisis. So it is refreshing to hear from a theorist - one who was deeply involved with string theory and championed it in his previous book, Three Roads to Quantum Gravity - that all is not well in this closeted realm. Smolin argues from the outset that viable hypotheses must lead to observable consequences by which they can be tested and judged. String theory by its very nature does not allow for such probing, according to Smolin, and therefore it must be considered as an unprovable conjecture. Towards the end of his book, Smolin suggests other directions fundamental physics can take, particularly in the realm of quantum gravity, to resolve its crisis and reconnect with the observable world. From my perspective, he leans a bit too heavily towards highly speculative ideas such as doubly special relativity, modified Newtonian

  3. Axions in String Theory

    Energy Technology Data Exchange (ETDEWEB)

    Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC; Witten, Edward; /Princeton, Inst. Advanced Study

    2006-06-09

    In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.

  4. Fractional bosonic strings

    Science.gov (United States)

    Diaz, Victor Alfonzo; Giusti, Andrea

    2018-03-01

    The aim of this paper is to present a simple generalization of bosonic string theory in the framework of the theory of fractional variational problems. Specifically, we present a fractional extension of the Polyakov action, for which we compute the general form of the equations of motion and discuss the connection between the new fractional action and a generalization the Nambu-Goto action. Consequently, we analyze the symmetries of the modified Polyakov action and try to fix the gauge, following the classical procedures. Then we solve the equations of motion in a simplified setting. Finally, we present a Hamiltonian description of the classical fractional bosonic string and introduce the fractional light-cone gauge. It is important to remark that, throughout the whole paper, we thoroughly discuss how to recover the known results as an "integer" limit of the presented model.

  5. Identità individuale e prassi musicale in contesti interculturali. L’esperienza della West-Eastern Divan Orchestra

    Directory of Open Access Journals (Sweden)

    DIANA, Rosario

    2012-11-01

    Full Text Available [Individual identity and musical practice in intercultural contexts. The experience of the West-Eastern Divan Orchestra]. This article focuses on the famous youth orchestra founded in 1999 by Daniel Barenboim and Edward Said. Every year, young musicians from Israel and Arab countries together spend a period of training and playing in an orchestra that holds concerts all over the world. According Barenboim and Said this promotes mutual understanding between people coming from geopolitical and national realities in conflict. This article focuses on the philosophical and intercultural meaning of this experience and interprets it according to the theory of multiple identities by Amartya Sen and the specificity of the language of music.

  6. The theta-structure in string theories - 1: bosonic strings

    International Nuclear Information System (INIS)

    Li Miao.

    1985-09-01

    We explored the theta-structures in bosonic string theories which are similar to those in gauge field theories. The theta-structure of string is due to the multiply connected spatial compact subspace of space-time. The work of this paper shows that there is an energy band E(theta) in the string theory and one may move the tachyon out in theory by choosing some proper theta parameters. (author)

  7. Half-string oscillator approach to string field theory

    International Nuclear Information System (INIS)

    Bordes, J.; Chan Hongmo; Nellen, L.; Tsou Sheungtsun

    1989-05-01

    We give an operator formulation of the string field theory proposed by E. Witten using half-string oscillator modes. This formalism, identifying the physical string states as infinite matrices, is developed in such a way that interactions at the level of vertices can be calculated in terms of products and traces of these matrices without relying on ill-defined manipulations of functional integrals. (author)

  8. Quantized string models

    Energy Technology Data Exchange (ETDEWEB)

    Fradkin, E.S.; Tseytlin, A.A.

    1982-10-15

    We discuss and compare the Lorentz covariant path integral quantization of the three bose string models, namely, the Nambu, Eguchi and Brink-Di Vecchai-Howe-Polyakov (BDHP) ones. Along with a critical review of the subject with some uncertainties and ambiguities clearly stated, various new results are presented. We work out the form of the BDHP string ansatz for the Wilson average and prove a formal inequivalence of the exact Nambu and BDHP models for any space-time dimension d. The above three models known to be equivalent on the classical level, are shown to be equivalent in a semiclassical approximation near a minimal surface and also in the leading 1/d-approximation for the static q-barq-potential. We analyze scattering amplitudes predicted by the BDHP string and find that when exactly calculated for d<26 they are different from the old dual ones, and possess a non-linear spectrum which may be considered as free from tachyons in the ground state.

  9. Fingerprints in Compressed Strings

    DEFF Research Database (Denmark)

    Bille, Philip; Cording, Patrick Hagge; Gørtz, Inge Li

    2013-01-01

    The Karp-Rabin fingerprint of a string is a type of hash value that due to its strong properties has been used in many string algorithms. In this paper we show how to construct a data structure for a string S of size N compressed by a context-free grammar of size n that answers fingerprint queries....... That is, given indices i and j, the answer to a query is the fingerprint of the substring S[i,j]. We present the first O(n) space data structures that answer fingerprint queries without decompressing any characters. For Straight Line Programs (SLP) we get O(logN) query time, and for Linear SLPs (an SLP...... derivative that captures LZ78 compression and its variations) we get O(loglogN) query time. Hence, our data structures has the same time and space complexity as for random access in SLPs. We utilize the fingerprint data structures to solve the longest common extension problem in query time O(logNlogℓ) and O...

  10. An invariant string propagator

    International Nuclear Information System (INIS)

    Cohen, A.; Moore, G.; Nelson, P.; Polchinski, J.

    1986-01-01

    The authors show that the Polyakov path integral is used to define off-shell quantities in string theory. The path integral of Polyakov gives an elegant description of strings and their interactions. However, its use has been limited to obtaining the Koba-Nielsen expressions for S-matrix elements. It is not yet clear what quantities make sense in string theory. This study shows that the path integral can be used to define off-shell quantities as well. In particular it defines a natural n-point function in loop space as the sum of all world surfaces bounded by n specific spacetime curves. The reader is referred for more detail. The report first outlines general evaluation then discusses the additional features added by boundaries. Locally, the three gauge freedoms ξ/sup a/ and δphi can be used to take g/sub ab/ (σ) to the unit matrix. Globally, this is not quite possible. In general the researchers choose a family of fiducial metrics g/sub ab/ (σ,tau), depending on a finite number of Teichmuller parameters tau, and every metric is gauge equivalent to one of these

  11. MicroRNAs as new maestro conducting the expanding symphony orchestra of regenerative and reparative medicine

    OpenAIRE

    Sen, Chandan K.

    2011-01-01

    The human genome encodes 1,048 microRNAs (miRNAs). These miRNAs regulate virtually all biological processes. Leaving ignominy on the significance miRNAs behind we are approaching a new era in tissue repair where an ever expanding orchestra of events that enable tissue repair and regeneration seems to be conducted by miRNAs as the maestro. microRNAs are emerging as molecular rheostats that fine-tune and switch regulatory circuits governing tissue repair. Key elements of tissue repair such as s...

  12. How to simulate global cosmic strings with large string tension

    Energy Technology Data Exchange (ETDEWEB)

    Klaer, Vincent B.; Moore, Guy D., E-mail: vklaer@theorie.ikp.physik.tu-darmstadt.de, E-mail: guy.moore@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 2, Darmstadt, D-64289 Germany (Germany)

    2017-10-01

    Global string networks may be relevant in axion production in the early Universe, as well as other cosmological scenarios. Such networks contain a large hierarchy of scales between the string core scale and the Hubble scale, ln( f {sub a} / H ) ∼ 70, which influences the network dynamics by giving the strings large tensions T ≅ π f {sub a} {sup 2} ln( f {sub a} / H ). We present a new numerical approach to simulate such global string networks, capturing the tension without an exponentially large lattice.

  13. Maximal unbordered factors of random strings

    DEFF Research Database (Denmark)

    Cording, Patrick Hagge; Knudsen, Mathias Bæk Tejs

    2016-01-01

    A border of a string is a non-empty prefix of the string that is also a suffix of the string, and a string is unbordered if it has no border. Loptev, Kucherov, and Starikovskaya [CPM 2015] conjectured the following: If we pick a string of length n from a fixed alphabet uniformly at random...

  14. Counting Dependent and Independent Strings

    Science.gov (United States)

    Zimand, Marius

    We derive quantitative results regarding sets of n-bit strings that have different dependency or independency properties. Let C(x) be the Kolmogorov complexity of the string x. A string y has α dependency with a string x if C(y) - C(y |x) ≥ α. A set of strings {x 1, ..., x t } is pairwise α-independent if for all inot=j, C(x i ) - C(x i |x j ) ≤ α. A tuple of strings (x 1, ..., x t ) is mutually α-independent if C(x π(1) ... x π(t)) ≥ C(x 1) + ... + C(x t ) - α, for every permutation π of [t]. We show that:

  15. Quantum backreaction in string theory

    International Nuclear Information System (INIS)

    Evnin, O.

    2012-01-01

    There are situations in string theory when a finite number of string quanta induce a significant backreaction upon the background and render the perturbation theory infrared-divergent. The simplest example is D0-brane recoil under an impact by closed strings. A more physically interesting case is backreaction on the evolution of a totally compact universe due to closed string gas. Such situations necessitate qualitative amendments to the traditional formulation of string theory in a fixed classical background. In this contribution to the proceedings of the XVII European Workshop on String Theory in Padua, I review solved problems and current investigations in relation to this kind of quantum backreaction effects. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Comparing double string theory actions

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, L. [Dipartimento di Fisica, Università degli Studi “Federico II” di Napoli,Complesso Universitario Monte S. Angelo ed. 6, via Cintia, 80126 Napoli (Italy); Gionti, S.J.G. [Specola Vaticana, Vatican City, V-00120, Vatican City State and Vatican Observatory Research Group, Steward Observatory, The University Of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721 (United States); Marotta, R.; Pezzella, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli,Complesso Universitario di Monte S. Angelo ed. 6, via Cintia, 80126 Napoli (Italy)

    2014-04-28

    Aimed to a deeper comprehension of a manifestly T-dual invariant formulation of string theory, in this paper a detailed comparison between the non-covariant action proposed by Tseytlin and the covariant one proposed by Hull is done. These are obtained by making both the string coordinates and their duals explicitly appear, on the same footing, in the world-sheet action, so “doubling” the string coordinates along the compact dimensions. After a discussion on the nature of the constraints in both the models and the relative quantization, it results that the string coordinates and their duals behave like “non-commuting” phase space coordinates but their expressions in terms of Fourier modes generate the oscillator algebra of the standard bosonic string. A proof of the equivalence of the two formulations is given. Furthermore, open-string solutions are also discussed.

  17. Comparing double string theory actions

    International Nuclear Information System (INIS)

    De Angelis, L.; Gionti, S.J.G.; Marotta, R.; Pezzella, F.

    2014-01-01

    Aimed to a deeper comprehension of a manifestly T-dual invariant formulation of string theory, in this paper a detailed comparison between the non-covariant action proposed by Tseytlin and the covariant one proposed by Hull is done. These are obtained by making both the string coordinates and their duals explicitly appear, on the same footing, in the world-sheet action, so “doubling” the string coordinates along the compact dimensions. After a discussion on the nature of the constraints in both the models and the relative quantization, it results that the string coordinates and their duals behave like “non-commuting” phase space coordinates but their expressions in terms of Fourier modes generate the oscillator algebra of the standard bosonic string. A proof of the equivalence of the two formulations is given. Furthermore, open-string solutions are also discussed

  18. Fast Searching in Packed Strings

    DEFF Research Database (Denmark)

    Bille, Philip

    2009-01-01

    Given strings P and Q the (exact) string matching problem is to find all positions of substrings in Q matching P. The classical Knuth-Morris-Pratt algorithm [SIAM J. Comput., 1977] solves the string matching problem in linear time which is optimal if we can only read one character at the time....... However, most strings are stored in a computer in a packed representation with several characters in a single word, giving us the opportunity to read multiple characters simultaneously. In this paper we study the worst-case complexity of string matching on strings given in packed representation. Let m...... word-RAM with logarithmic word size we present an algorithm using time O(n/log(sigma) n + m + occ) Here occ is the number of occurrences of P in Q. For m = o(n) this improves the O(n) bound...

  19. Classical theory of radiating strings

    Science.gov (United States)

    Copeland, Edmund J.; Haws, D.; Hindmarsh, M.

    1990-01-01

    The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.

  20. Introduction to strings and superstrings

    International Nuclear Information System (INIS)

    Traubenberg, M.R. de.

    1988-01-01

    We discuss the main features on the formulation of string theory that, in a primitive level, describe the hadronic phenomenon of duality. We also study an extension of the models of closed and strings with spin. Then, by using supersymmetry, it is formulated the theory of superstrings and heterotic strings with the aim of unify the fundamental interactions and matter. (M.W.O.) [pt

  1. Cosmic strings and galaxy formation

    International Nuclear Information System (INIS)

    Kibble, T.W.B.

    1986-01-01

    The evolution of a system of strings created at a phase transition early in the history of the universe is reviewed. The two possible end points are a string-dominated universe, which behaves much like a matter-dominated one, and a scaling solution, in which the persistence length of the system of strings scales with the horizon distance. The latter is the basis for a very attractive theory of galaxy formation. (Auth.)

  2. Domain Walls with Strings Attached

    Energy Technology Data Exchange (ETDEWEB)

    Shmakova, Marina

    2001-08-20

    We have constructed a bulk and brane action of IIA theory which describes a pair of BPS domain walls on S{sub 1}/Z{sub 2}, with strings attached. The walls are given by two orientifold O8-planes with coincident D8-branes and F1-D0-strings are stretched between the walls. This static configuration satisfies all matching conditions for the string and domain wall sources and has 1/4 of unbroken supersymmetry.

  3. Splitting strings on integrable backgrounds

    International Nuclear Information System (INIS)

    Vicedo, Benoit

    2011-05-01

    We use integrability to construct the general classical splitting string solution on R x S 3 . Namely, given any incoming string solution satisfying a necessary self-intersection property at some given instant in time, we use the integrability of the worldsheet σ-model to construct the pair of outgoing strings resulting from a split. The solution for each outgoing string is expressed recursively through a sequence of dressing transformations, the parameters of which are determined by the solutions to Birkhoff factorization problems in an appropriate real form of the loop group of SL 2 (C). (orig.)

  4. String Theory in a Nutshell

    CERN Document Server

    Kiritsis, Elias

    2007-01-01

    This book is the essential new introduction to modern string theory, by one of the world's authorities on the subject. Concise, clearly presented, and up-to-date, String Theory in a Nutshell brings together the best understood and most important aspects of a theory that has been evolving since the early 1980s. A core model of physics that substitutes one-dimensional extended ""strings"" for zero-dimensional point-like particles (as in quantum field theory), string theory has been the leading candidate for a theory that would successfully unify all fundamental forces of nature, includin

  5. Evolution of cosmic string networks

    International Nuclear Information System (INIS)

    Albrecht, A.; Turok, N.; Princeton Univ., NJ

    1989-06-01

    We summarize our new results on cosmic strings. These results include: the application of non-equilibrium statistical mechanics to cosmic string evolution, a simple ''one scale'' model for the long strings which has a great deal of predictive power, results from large scale numerical simulations, and a discussion of the observational consequences of our results. An upper bond on Gμ of approximately 10 -7 emerges from the millisecond pulsar gravity wave bound. We discuss how numerical uncertainties affect this. Any changes which weaken the bound would probably also give the long strings the dominant role in producing observational consequences. 22 refs

  6. The ABCDEFG of Little Strings

    OpenAIRE

    Haouzi, Nathan; Kozçaz, Can

    2017-01-01

    Starting from type IIB string theory on an $ADE$ singularity, the (2,0) little string arises when one takes the string coupling $g_s$ to 0. In this setup, we give a unified description of the codimension-two defects of the little string, for any simple Lie algebra ${\\mathfrak{g}}$. Geometrically, these are D5 branes wrapping 2-cycles of the singularity. Equivalently, the defects are specified by a certain set of weights of $^L {\\mathfrak{g}}$, the Langlands dual of ${\\mathfrak{g}}$. As a firs...

  7. A primer on string theory

    CERN Document Server

    Schomerus, Volker

    2017-01-01

    Since its conception in the 1960s, string theory has been hailed as one of the most promising routes we have to unify quantum mechanics and general relativity. This book provides a concise introduction to string theory explaining central concepts, mathematical tools and covering recent developments in physics including compactifications and gauge/string dualities. With string theory being a multidisciplinary field interfacing with high energy physics, mathematics and quantum field theory, this book is ideal for both students with no previous knowledge of the field and scholars from other disciplines who are looking for an introduction to basic concepts.

  8. Healthy Vision Tips

    Science.gov (United States)

    ... for Kids >> Healthy Vision Tips Listen All About Vision About the Eye Ask a Scientist Video Series ... Links to More Information Optical Illusions Printables Healthy Vision Tips Healthy vision starts with you! Use these ...

  9. Hearing loss induced by loud music among musicians of symphonic orchestra

    Directory of Open Access Journals (Sweden)

    Tanja Carli

    2012-12-01

    Full Text Available Noise-induced hearing loss is an important public health issue, especially among musicians who are, more than any other occupation, dependent on their hearing. For them, hearing impairment is due to too loud music, the effect of which, if exceeding the limit depending on the individual sensitivity of one’s ear, can be compared with theeffect of noise on the ear. Risk factors for its development are: the type of musical instrument and sound character, the way of playing, music genre or composition, duration of exposure to loud music, sound source and its distance from the ear, intervals of acoustic stimuli, individual factors and the musician’s position in the orchestra. Hearing impairment is greater at higher frequencies; in pure tone audiogram it is shown as notches between 3000 and 6000 Hz and is most frequent in the wind and brass section. Hearing loss is greater among violinists and typically affects the left ear owing to the sound source proximity and their position in the orchestra. The most common health problems take the form of diplacusis, algiacusis and tinnitus, as exposure to the loud acoustic stimulus above 90 dB(A cause damage to the inner ear, the so-called acoustic trauma. Use of personal protective equipment among musicians is low especially because of too much high-frequency attenuation and occlusion effect.

  10. Diabetes Mellitus as Dysfunction of Interactions among all Organs: “Ominous Orchestra of Organs”

    Directory of Open Access Journals (Sweden)

    Hiroyuki Koshiyama

    2008-01-01

    Full Text Available Epidemiological evidence has established a link among hyperlipidemia, visceral obesity, osteoporosis, and cardiovascular diseases. We have recently proposed a hypothesis that the associations of those disorders are based on interactions of the three organs, i.e. the bone, adipose, and vascular tissues, possibly through multiple actions of several humoral factors and/or transcription factors. We call this unified hypothesis “osteo-lipo-vascular interactions”, which may be explained by the common origin of the cells in each organ, such as mesenchymal stem cells or macrophages. Several groups proposed similar hypotheses. On the other hand, there have been accumulating evidences which indicate that there exist hitherto unknown various interactions between many organs, such as hypothalamus-liver, fat-liver, liver-muscle, intestine-pancreas, kidney-heart and so on. Therefore, it seems insufficient to consider only the interactions among several organs, and the standpoint of considering interactions among all organs may be warranted, especially in order to understand the pathogenesis of metabolic syndrome, insulin resistance and type 2 diabetes. We here propose a hypothesis that the abnormal interactions of all organs (“Ominous Orchestra of Organs” underlies the pathogenesis of type 2 diabetes. It is to be elucidated which of the “players” or the “conductor” may be mainly responsible for disharmony of the orchestra.

  11. Digestive Health Tips

    Science.gov (United States)

    ... Home / Digestive Health Topic / Digestive Health Tips Digestive Health Tips Basics 10 Tips on Belching, Bloating, and Flatulence Belching is caused by swallowed air from: Eating or drinking too fast Poorly fitting dentures; not chewing food completely Carbonated beverages Chewing gum or sucking on ...

  12. Strings, Branes and Symmetries

    International Nuclear Information System (INIS)

    Westerberg, A.

    1997-01-01

    Recent dramatic progress in the understanding of the non-perturbative structure of superstring theory shows that extended objects of various kinds, collectively referred to as p-branes, are an integral part of the theory. In this thesis, comprising an introductory text and seven appended research papers, we study various aspects of p-branes with relevance for superstring theory. The first part of the introductory text is a brief review of string theory focussing on the role of p-branes. In particular, we consider the so-called D-branes which currently are attracting a considerable amount of attention. The purpose of this part is mainly to put into context the results of paper 4, 5 and 6 concerning action functionals describing the low-energy dynamics of D-branes. The discussion of perturbative string theory given in this part of the introduction is also intended to provide some background to paper 2 which contains an application of the Reggeon-sewing approach to the construction of string vertices. The second part covers a rather different subject, namely higher-dimensional loop algebras and their cohomology, with the aim of facilitating the reading of papers 1, 3 and 7. The relation to p-branes is to be found in paper 1 where we introduce a certain higher-dimensional generalization of the loop algebra and discuss its potential applicability as a symmetry algebra for p-branes. Papers 3 and 7 are mathematically oriented out-growths of this paper addressing the issue of realizing algebras of this kind, known in physics as current algebras, in terms of pseudo differential operators (PSDOs). The main result of paper 3 is a proof of the equivalence between certain Lie-algebra cocycles on the space of second-quantizable PSDOs

  13. Drill string gas data

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, E.R.

    1998-05-12

    Data and supporting documentation were compiled and analyzed for 26 cases of gas grab samples taken during waste-tank core sampling activities between September 1, 1995 and December 31, 1997. These cases were tested against specific criteria to reduce uncertainties associated with in-tank sampling location and conditions. Of the 26 possible cases, 16 qualified as drill-string grab samples most likely to represent recently released waste gases. The data from these 16 ``confirmed`` cases were adjusted to remove non-waste gas contributions from core-sampling activities (argon or nitrogen purge), the atmospheric background, and laboratory sampler preparation (helium). The procedure for subtracting atmospheric, laboratory, and argon purge gases was unambiguous. No reliable method for determining the exact amount of nitrogen purge gas was established. Thus, the final set of ``Adjusted`` drill string gas data for the 6 nitrogen-purged cases had a greater degree of uncertainty than the final results for the 10 argon-purged cases. Including the appropriate amounts of uncertainty, this final set of data was added to the set of high-quality results from the Retained Gas Sampler (RGS), and good agreement was found for the N{sub 2}, H{sub 2}, and N{sub 2}O mole fractions sampled from common tanks. These results indicate that under favorable sampling conditions, Drill-String (DS) grab samples can provide reasonably accurate information about the dominant species of released gas. One conclusion from this set of total gas data is that the distribution of the H{sub 2} mole fractions is bimodal in shape, with an upper bound of 78%.

  14. String-inspired cosmology

    International Nuclear Information System (INIS)

    Wands, David

    2002-01-01

    I discuss cosmological models either derived from, or inspired by, string theory or M-theory. In particular, I discuss solutions in the low-energy effective theory and the role of the dilaton, moduli and antisymmetric form fields in the dimensionally reduced effective action. The pre-big-bang model is an attempt to use cosmological solutions to make observational predictions. I then discuss the effective theory of gravity found in recent braneworld models where we live on a 3-brane embedded in a five-dimensional spacetime and how the study of cosmological perturbations may enable us to test these ideas

  15. Nuclear fuel string assembly

    International Nuclear Information System (INIS)

    Ip, A.K.; Koyanagi, K.; Tarasuk, W.R.

    1976-01-01

    A method of fabricating rodded fuels suitable for use in pressure tube type reactors and in pressure vessel type reactors is described. Fuel rods are secured as an inner and an outer sub-assembly, each rod attached between mounting rings secured to the rod ends. The two sub-assemblies are telescoped together and positioned by spaced thimbles located between them to provide precise positioning while permittng differential axial movement between the sub-assemblies. Such sub-assemblies are particularly suited for mounting as bundle strings. The method provides particular advantages in the assembly of annular-section fuel pins, which includes booster fuel containing enriched fuel material. (LL)

  16. Sequestering in String Theory

    Energy Technology Data Exchange (ETDEWEB)

    Kachru, Shamit; McAllister, Liam; Sundrum, Raman

    2007-04-04

    We study sequestering, a prerequisite for flavor-blind supersymmetry breaking in several high-scale mediation mechanisms, in compactifications of type IIB string theory. We find that although sequestering is typically absent in unwarped backgrounds, strongly warped compactifications do readily sequester. The AdS/CFT dual description in terms of conformal sequestering plays an important role in our analysis, and we establish how sequestering works both on the gravity side and on the gauge theory side. We pay special attention to subtle compactification effects that can disrupt sequestering. Our result is a step toward realizing an appealing pattern of soft terms in a KKLT compactification.

  17. Sequestering in string theory

    International Nuclear Information System (INIS)

    Kachru, Shamit; McAllister, Liam; Sundrum, Raman

    2007-01-01

    We study sequestering, a prerequisite for flavor-blind supersymmetry breaking in several high-scale mediation mechanisms, in compactifications of type IIB string theory. We find that although sequestering is typically absent in unwarped backgrounds, strongly warped compactifications do readily sequester. The AdS/CFT dual description in terms of conformal sequestering plays an important role in our analysis, and we establish how sequestering works both on the gravity side and on the gauge theory side. We pay special attention to subtle compactification effects that can disrupt sequestering. Our result is a step toward realizing an appealing pattern of soft terms in a KKLT compactification

  18. Transmutations for Strings

    Directory of Open Access Journals (Sweden)

    Amin Boumenir

    2008-07-01

    Full Text Available We investigate the existence and representation of transmutations, also known as transformation operators, for strings. Using measure theory and functional analytic methods we prove their existence and study their representation. We show that in general they are not close to unity since their representation does not involve a Volterra operator but rather the eigenvalue parameter. We also obtain conditions under which the transmutation is either a bounded or a compact operator. Explicit examples show that they cannot be reduced to Volterra type operators.  

  19. New ambitwistor string theories

    Energy Technology Data Exchange (ETDEWEB)

    Casali, Eduardo [DAMTP, University of Cambridge,Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Geyer, Yvonne; Mason, Lionel; Monteiro, Ricardo [Mathematical Institute, University of Oxford,Woodstock Road, Oxford OX2 6GG (United Kingdom); Roehrig, Kai A. [DAMTP, University of Cambridge,Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2015-11-05

    We describe new ambitwistor string theories that give rise to the recent amplitude formulae for Einstein-Yang-Mills, (Dirac)-Born-Infeld, Galileons and others introduced by Cachazo, He and Yuan. In the case of the Einstein-Yang-Mills amplitudes, an important role is played by a novel worldsheet conformal field theory that provides the appropriate colour factors precisely without the spurious multitrace terms of earlier models that had to be ignored by hand. This is needed to obtain the correct multitrace terms that arise when Yang-Mills is coupled to gravity.

  20. Memorization for String Players.

    Science.gov (United States)

    Kopfstein-Penk, Alicia

    1997-01-01

    Discusses the benefits of using mental-memorization techniques in conjunction with kinesthetic memory. Expounds that memorization helps students feel both more secure and musical. Describes several kinds of memory: physical kinesthetic, mental kinesthetic, visual memory, aural memory, and structural memory. Gives tips for strengthening memory and…

  1. Tip studies using CFD and comparison with tip loss models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Johansen, J.

    2004-01-01

    The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

  2. Energy in a String Wave

    Science.gov (United States)

    Ng, Chiu-king

    2010-01-01

    When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed…

  3. Experimenting with String Musical Instruments

    Science.gov (United States)

    LoPresto, Michael C.

    2012-01-01

    What follows are several investigations involving string musical instruments developed for and used in a "Science of Sound & Light" course. The experiments make use of a guitar, orchestral string instruments and data collection and graphing software. They are designed to provide students with concrete examples of how mathematical formulae, when…

  4. Cool Runnings For String 2

    CERN Multimedia

    2001-01-01

    String 2 is a series of superconducting magnets that are prototypes of those which will be installed in the LHC. It was cooled down to 1.9 Kelvin on September 14th. On Thursday last week, the dipoles of String 2 were successfully taken to nominal current, 11850 A.

  5. Differential formulation in string theories

    International Nuclear Information System (INIS)

    Guzzo, M.M.

    1987-01-01

    The equations of gauge invariance motion for theories of boson open strings and Neveu-Schwarz and Ramond superstring are derived. A construction for string theories using differential formalism, is introduced. The importance of BRST charge for constructing such theories and the necessity of introduction of auxiliary fields are verified. (M.C.K.) [pt

  6. Progress in string theory research

    CERN Document Server

    2016-01-01

    At the first look, the String Theory seems just an interesting and non-trivial application of the quantum mechanics and the special relativity to vibrating strings. By itself, the quantization of relativistic strings does not call the attention of the particle physicist as a significant paradigm shift. However, when the string quantization is performed by applying the standard rules of the perturbative Quantum Field Theory, one discovers that the strings in certain states have the same physical properties as the gravity in the flat space-time. Chapter one of this book reviews the construction of the thermal bosonic string and D-brane in the framework of the Thermo Field Dynamics (TFD). It briefly recalls the wellknown light-cone quantization of the bosonic string in the conformal gauge in flat space-time, and gives a bird’s eye view of the fundamental concepts of the TFD. Chapter two examines a visual model inspired by string theory, on the system of interacting anyons. Chapter three investigate the late-ti...

  7. Deformations of topological open strings

    NARCIS (Netherlands)

    Hofman, C.; Ma, Whee Ky

    Deformations of topological open string theories are described, with an emphasis on their algebraic structure. They are encoded in the mixed bulk-boundary correlators. They constitute the Hochschild complex of the open string algebra - the complex of multilinear maps on the boundary Hilbert space.

  8. Tadpole resummations in string theory

    International Nuclear Information System (INIS)

    Kitazawa, Noriaki

    2008-01-01

    While R-R tadpoles should be canceled for consistency, string models with broken supersymmetry generally have uncanceled NS-NS tadpoles. Their presence signals that the background does not solve the field equations, so that these models are in 'wrong' vacua. In this Letter we investigate, with reference to some prototype examples, whether the true values of physical quantities can be recovered resumming the NS-NS tadpoles, hence by an approach that is related to the analysis based on String Field Theory by open-closed duality. We show that, indeed, the positive classical vacuum energy of a Dp-brane of the bosonic string is exactly canceled by the negative contribution arising from tree-level tadpole resummation, in complete agreement with Sen's conjecture on open-string tachyon condensation and with the consequent analysis based on String Field Theory. We also show that the vanishing classical vacuum energy of the SO(8192) unoriented bosonic open-string theory does not receive any tree-level corrections from the tadpole resummation. This result is consistent with the fact that this (unstable) configuration is free from tadpoles of massless closed-string modes, although there is a tadpole of the closed string tachyon. The application of this method to superstring models with broken supersymmetry is also discussed

  9. String theory and water waves

    International Nuclear Information System (INIS)

    Iyer, Ramakrishnan; Johnson, Clifford V; Pennington, Jeffrey S

    2011-01-01

    We uncover a remarkable role that an infinite hierarchy of nonlinear differential equations plays in organizing and connecting certain c-hat <1 string theories non-perturbatively. We are able to embed the type 0A and 0B (A, A) minimal string theories into this single framework. The string theories arise as special limits of a rich system of equations underpinned by an integrable system known as the dispersive water wave hierarchy. We observe that there are several other string-like limits of the system, and conjecture that some of them are type IIA and IIB (A, D) minimal string backgrounds. We explain how these and several string-like special points arise and are connected. In some cases, the framework endows the theories with a non-perturbative definition for the first time. Notably, we discover that the Painleve IV equation plays a key role in organizing the string theory physics, joining its siblings, Painleve I and II, whose roles have previously been identified in this minimal string context.

  10. String-localized quantum fields

    International Nuclear Information System (INIS)

    Mund, Jens; Santos, Jose Amancio dos; Silva, Cristhiano Duarte; Oliveira, Erichardson de

    2009-01-01

    Full text. The principles of physics admit (unobservable) quantum fields which are localized not on points, but on strings in the sense of Mandelstam: a string emanates from a point in Minkowski space and extends to infinity in some space-like direction. This type of localization might permit the construction of new models, for various reasons: (a) in general, weaker localization implies better UV behaviour. Therefore, the class of renormalizable interactions in the string-localized has a chance to be larger than in the point-localized case; (b) for certain particle types, there are no point-localized (free) quantum fields - for example Anyons in d = 2 + 1, and Wigner's massless 'infinite spin' particles. For the latter, free string-localized quantum fields have been constructed; (c) in contrast to the point-localized case, string-localization admits covariant vector/tensor potentials for fotons and gravitons in a Hilbert space representation with positive energy. We shall present free string-localized quantum fields for various particle types, and some ideas about the perturbative construction of interacting string-localized fields. A central point will be an analogue of gauge theories, completely within a Hilbert space and without ghosts, trading gauge dependence with dependence on the direction of the localization string. In order to discuss renormalizability (item (a)), methods from microlocal analysis (wave front set and scaling degree) are needed. (author)

  11. String theory and cosmological singularities

    Indian Academy of Sciences (India)

    recent times, string theory is providing new perspectives of such singularities which may lead to an understanding of these in the standard framework of time evolution in quantum mechanics. In this article, we describe some of these approaches. Keywords. String theory; cosmological singularities. PACS Nos 11.25.

  12. String theory and particle physics

    International Nuclear Information System (INIS)

    Uranga, Angel

    2006-01-01

    I will provide a basic introduction to string theory as a unified theory of gravitational and gauge interactions. I will review recent constructions of string theory models leading at low energies to the Standard Model of particle interactions, and which include interesting new phenomenology beyond the standard model, like supersymmetry, boranes, and (possible large) extra dimensions

  13. Bianchi type I string cosmologies

    Indian Academy of Sciences (India)

    sidered to portray early universe reasonably well. Letelier [2] obtained some particular. Bianchi type I string-dust models in which at a certain epoch, strings disappear with a phase transition to an anisotropic fluid. Another Bianchi type I model has been presented by Banerjee et al [3] which obeys Takabayashi's equation of ...

  14. String theory : physics or metaphysics?

    CERN Document Server

    Veneziano, Gabriele

    2010-01-01

    I will give arguments for why the enormous progress made during the last century on understanding elementary particles and their fundamental interactions suggests strings as the truly elementary constituents of Nature. I will then address the issue of whether the string paradigm can in principle be falsified or whether it should be considered as mere metaphysics.

  15. Understanding Your Band, Orchestra, and Choir Students: Personality Similarities and Differences and What They Mean for You

    Science.gov (United States)

    MacLellan, Christin Reardon

    2011-01-01

    Stereotypes about the personalities of musicians, which have evolved over time, seem to direct our perception of musical experiences that take place in different ensembles. This article presents the stereotypes often associated with musicians' personalities and examines eight personality trends of high school band, orchestra, and choir students…

  16. The TIPS Liquidity Premium

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

    We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, like...... most fixed-income securities, go into buy-and-hold investors' portfolios as time passes. We find a sizable and countercyclical TIPS liquidity premium, which greatly helps our model in matching TIPS prices. Accounting for liquidity risk also improves the model's ability to forecast inflation and match...

  17. Poisson hierarchy of discrete strings

    Energy Technology Data Exchange (ETDEWEB)

    Ioannidou, Theodora, E-mail: ti3@auth.gr [Faculty of Civil Engineering, School of Engineering, Aristotle University of Thessaloniki, 54249, Thessaloniki (Greece); Niemi, Antti J., E-mail: Antti.Niemi@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 803, S-75108, Uppsala (Sweden); Laboratoire de Mathematiques et Physique Theorique CNRS UMR 6083, Fédération Denis Poisson, Université de Tours, Parc de Grandmont, F37200, Tours (France); Department of Physics, Beijing Institute of Technology, Haidian District, Beijing 100081 (China)

    2016-01-28

    The Poisson geometry of a discrete string in three dimensional Euclidean space is investigated. For this the Frenet frames are converted into a spinorial representation, the discrete spinor Frenet equation is interpreted in terms of a transfer matrix formalism, and Poisson brackets are introduced in terms of the spinor components. The construction is then generalised, in a self-similar manner, into an infinite hierarchy of Poisson algebras. As an example, the classical Virasoro (Witt) algebra that determines reparametrisation diffeomorphism along a continuous string, is identified as a particular sub-algebra, in the hierarchy of the discrete string Poisson algebra. - Highlights: • Witt (classical Virasoro) algebra is derived in the case of discrete string. • Infinite dimensional hierarchy of Poisson bracket algebras is constructed for discrete strings. • Spinor representation of discrete Frenet equations is developed.

  18. Poisson hierarchy of discrete strings

    International Nuclear Information System (INIS)

    Ioannidou, Theodora; Niemi, Antti J.

    2016-01-01

    The Poisson geometry of a discrete string in three dimensional Euclidean space is investigated. For this the Frenet frames are converted into a spinorial representation, the discrete spinor Frenet equation is interpreted in terms of a transfer matrix formalism, and Poisson brackets are introduced in terms of the spinor components. The construction is then generalised, in a self-similar manner, into an infinite hierarchy of Poisson algebras. As an example, the classical Virasoro (Witt) algebra that determines reparametrisation diffeomorphism along a continuous string, is identified as a particular sub-algebra, in the hierarchy of the discrete string Poisson algebra. - Highlights: • Witt (classical Virasoro) algebra is derived in the case of discrete string. • Infinite dimensional hierarchy of Poisson bracket algebras is constructed for discrete strings. • Spinor representation of discrete Frenet equations is developed.

  19. Testing string theory at LHC?

    CERN Multimedia

    CERN. Geneva

    2002-01-01

    A theory with such mathematical beauty cannot be wrong: this is one of the main arguments in favour of string theory, which unifies all known physical theories of fundamental interactions in a single coherent description of the universe. But no one has ever observed strings, not even indirectly, nor the space of extra dimensions where they live. However there are good reasons to believe that the 'hidden' dimensions of string theory may be much larger than what we thought in the past and that they may be within experimental reach in the near future - together with the strings themselves. In my talk, I will give an elementary introduction of string theory and describe the main experimental predictions.Organiser(s): Jasper Kirkby / EP DivisionNote: Tea & coffee will be served at 16.00 hrs.

  20. Oscillons from string moduli

    Science.gov (United States)

    Antusch, Stefan; Cefalà, Francesco; Krippendorf, Sven; Muia, Francesco; Orani, Stefano; Quevedo, Fernando

    2018-01-01

    A generic feature of string compactifications is the presence of many scalar fields, called moduli. Moduli are usually displaced from their post-inflationary minimum during inflation. Their relaxation to the minimum could lead to the production of oscillons: localised, long-lived, non-linear excitations of the scalar fields. Here we discuss under which conditions oscillons can be produced in string cosmology and illustrate their production and potential phenomenology with two explicit examples: the case of an initially displaced volume modulus in the KKLT scenario and the case of a displaced blow-up Kähler modulus in the Large Volume Scenario (LVS). One, in principle, observable consequence of oscillon dynamics is the production of gravitational waves which, contrary to those produced from preheating after high scale inflation, could have lower frequencies, closer to the currently observable range. We also show that, for the considered parameter ranges, oscillating fibre and volume moduli do not develop any significant non-perturbative dynamics. Furthermore, we find that the vacua in the LVS and the KKLT scenario are stable against local overshootings of the field into the decompatification region, which provides an additional check on the longevity of these metastable configurations.

  1. Quark Confinement and Strings

    Science.gov (United States)

    't Hooft, Gerardus

    QCD was proposed as a theory for the strong interactions long before we had any idea as to how it could be that its fundamental constituents, the quarks, are never seen as physical particles. Massless gluons also do not exist as free particles. How can this be explained? The first indication that this question had to be considered in connection with the topological structure of a gauge theory came when Nielsen and Olesen observed the occurrence of stable magnetic vortex structures [1] in the Abelian Higgs model. Expanding on such ideas, the magnetic monopole solution was found [2]. Other roundabout attempts to understand confinement involve instantons. Today, we have better interpretations of these topological structures, including a general picture of the way they do lead to unbound potentials confining quarks. It is clear that these unbound potentials can be ascribed to a string-like structure of the vortices formed by the QCD field lines. Can string theory be used to analyze QCD? Many researchers think so. The leading expert on this is Sacha Polyakov. In his instructive account he adds how he experienced the course of events in Gauge Theory, emphasizing the fact that quite a few discoveries often ascribed to researchers from the West, actually were made independently by scientists from the Soviet Union…

  2. String dualities and superpotential

    International Nuclear Information System (INIS)

    Ha, Tae-Won

    2010-09-01

    The main objective of this thesis is the computation of the superpotential induced by D5- branes in the type IIB string theory and by five-branes in the heterotic string theory. Both superpotentials have the same functional form which is the chain integral of the holomorphic three-form. Using relative (co)homology we can unify the flux and brane superpotential. The chain integral can be seen as an example of the Abel-Jacobi map. We discuss many structures such as mixed Hodge structure which allows for the computation of Picard-Fuchs differential equations crucial for explicit computations. We blow up the Calabi-Yau threefold along the submanifold wrapped by the brane to obtain geometrically more appropriate configuration. The resulting geometry is non-Calabi-Yau and we have a canonically given divisor. This blown-up geometry makes it possible to restrict our attention to complex structure deformations. However, the direct computation is yet very difficult, thus the main tool for computation will be the lift of the brane configuration to a F-theory compactification. In F-theory, since complex structure, brane and, if present, bundlemoduli are all contained in the complex structure moduli space of the elliptic Calabi-Yau fourfold, the computation can be dramatically simplified. The heterotic/F-theory duality is extended to include the blow-up geometry and thereby used to give the blow-up geometry amore physical meaning. (orig.)

  3. String dualities and superpotential

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Tae-Won

    2010-09-15

    The main objective of this thesis is the computation of the superpotential induced by D5- branes in the type IIB string theory and by five-branes in the heterotic string theory. Both superpotentials have the same functional form which is the chain integral of the holomorphic three-form. Using relative (co)homology we can unify the flux and brane superpotential. The chain integral can be seen as an example of the Abel-Jacobi map. We discuss many structures such as mixed Hodge structure which allows for the computation of Picard-Fuchs differential equations crucial for explicit computations. We blow up the Calabi-Yau threefold along the submanifold wrapped by the brane to obtain geometrically more appropriate configuration. The resulting geometry is non-Calabi-Yau and we have a canonically given divisor. This blown-up geometry makes it possible to restrict our attention to complex structure deformations. However, the direct computation is yet very difficult, thus the main tool for computation will be the lift of the brane configuration to a F-theory compactification. In F-theory, since complex structure, brane and, if present, bundlemoduli are all contained in the complex structure moduli space of the elliptic Calabi-Yau fourfold, the computation can be dramatically simplified. The heterotic/F-theory duality is extended to include the blow-up geometry and thereby used to give the blow-up geometry amore physical meaning. (orig.)

  4. Twist Field as Three String Interaction Vertex in Light Cone String Field Theory

    OpenAIRE

    Kishimoto, Isao; Moriyama, Sanefumi; Teraguchi, Shunsuke

    2006-01-01

    It has been suggested that matrix string theory and light-cone string field theory are closely related. In this paper, we investigate the relation between the twist field, which represents string interactions in matrix string theory, and the three-string interaction vertex in light-cone string field theory carefully. We find that the three-string interaction vertex can reproduce some of the most important OPEs satisfied by the twist field.

  5. Arctic climate tipping points.

    Science.gov (United States)

    Lenton, Timothy M

    2012-02-01

    There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the Arctic are briefly reviewed. Then, the current behaviour of a range of Arctic systems is summarised. Looking ahead, a range of potential tipping phenomena are described. This leads to a revised and expanded list of potential Arctic climate tipping elements, whose likelihood is assessed, in terms of how much warming will be required to tip them. Finally, the available responses are considered, especially the prospects for avoiding Arctic climate tipping points.

  6. Oriented open-closed string theory revisited

    International Nuclear Information System (INIS)

    Zwiebach, B.

    1998-01-01

    String theory on D-brane backgrounds is open-closed string theory. Given the relevance of this fact, we give details and elaborate upon our earlier construction of oriented open-closed string field theory. In order to incorporate explicitly closed strings, the classical sector of this theory is open strings with a homotopy associative A ∞ algebraic structure. We build a suitable Batalin-Vilkovisky algebra on moduli spaces of bordered Ricmann surfaces, the construction of which involves a few subtleties arising from the open string punctures and cyclicity conditions. All vertices coupling open and closed strings through disks are described explicitly. Subalgebras of the algebra of surfaces with boundaries are used to discuss symmetries of classical open string theory induced by the closed string sector, and to write classical open string field theory on general closed string backgrounds. We give a preliminary analysis of the ghost-dilaton theorem. copyright 1998 Academic Press, Inc

  7. Conformal techniques in string theory and string field theory

    International Nuclear Information System (INIS)

    Giddings, S.B.

    1987-01-01

    The application of some conformal and Riemann surface techniques to string theory and string field theory is described. First a brief review of Riemann surface techniques and of the Polyakov approach to string theory is presented. This is followed by a discussion of some features of string field theory and of its Feynman rules. Specifically, it is shown that the Feynman diagrams for Witten's string field theory respect modular invariance, and in particular give a triangulation of moduli space. The Polyakov formalism is then used to derive the Feynman rules that should follow from this theory upon gauge-fixing. It should also be possible to apply this derivation to deduce the Feynman rules for other gauge-fixed string field theories. Following this, Riemann surface techniques are turned to the problem of proving the equivalence of the Polyakov and light-cone formalisms. It is first shown that the light-cone diagrams triangulate moduli space. Then the Polyakov measure is worked out for these diagrams, and shown to equal that deduced from the light-cone gauge fixed formalism. Also presented is a short description of the comparison of physical states in the two formalisms. The equivalence of the two formalisms in particular constitutes a proof of the unitarity of the Polyakov framework for the closed bosonic string

  8. Deterministic indexing for packed strings

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Skjoldjensen, Frederik Rye

    2017-01-01

    Given a string S of length n, the classic string indexing problem is to preprocess S into a compact data structure that supports efficient subsequent pattern queries. In the deterministic variant the goal is to solve the string indexing problem without any randomization (at preprocessing time...... or query time). In the packed variant the strings are stored with several character in a single word, giving us the opportunity to read multiple characters simultaneously. Our main result is a new string index in the deterministic and packed setting. Given a packed string S of length n over an alphabet σ......, we show how to preprocess S in O(n) (deterministic) time and space O(n) such that given a packed pattern string of length m we can support queries in (deterministic) time O (m/α + log m + log log σ), where α = w/log σ is the number of characters packed in a word of size w = θ(log n). Our query time...

  9. Extensions of string theories

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, R.; Barcelos-Neto, J. (Universidade Federal do Rio de Janeiro, RJ (Brazil). Inst. de Fisica)

    1993-06-01

    With the motivation that critical dimensions D[ne]4 might be suggeting that string theories have not been completely formulated, we study more general alternatives. We first consider a direct extension in the world-sheet formulation with N[sub B] bosons and N[sub F] fermions and analyze the conditions for canceling the anomaly in all possible combinations of N[sub B], N[sub F] and D. Later on we incorporate degrees of freedom of antisymmetric tensors to the previous model. The only possibility to cancel the anomaly in this case is with N[sub B]=N[sub F]=1 and the our everyday spacetime dimension D=4. (orig.).

  10. Fingerprints in compressed strings

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Cording, Patrick Hagge

    2017-01-01

    In this paper we show how to construct a data structure for a string S of size N compressed into a context-free grammar of size n that supports efficient Karp–Rabin fingerprint queries to any substring of S. That is, given indices i and j, the answer to a query is the fingerprint of the substring S......[i,j]. We present the first O(n) space data structures that answer fingerprint queries without decompressing any characters. For Straight Line Programs (SLP) we get O(log⁡N) query time, and for Linear SLPs (an SLP derivative that captures LZ78 compression and its variations) we get O(log⁡log⁡N) query time...

  11. Field theory and strings

    International Nuclear Information System (INIS)

    Bonara, L.; Cotta-Ramusino, P.; Rinaldi, M.

    1987-01-01

    It is well-known that type I and heterotic superstring theories have a zero mass spectrum which correspond to the field content of N=1 supergravity theory coupled to supersymmetric Yang-Mills theory in 10-D. The authors study the field theory ''per se'', in the hope that simple consistency requirements will determine the theory completely once one knows the field content inherited from string theory. The simplest consistency requirements are: N=1 supersymmetry; and absence of chiral anomalies. This is what the authors discuss in this paper here leaving undetermined the question of the range of validity of the resulting field theory. As is known, a model of N=1 supergravity (SUGRA) coupled to supersymmetric Yang-Mills (SYM) theory was known in the form given by Chapline and Manton. The coupling of SUGRA to SYM was determined by the definition of the ''field strength'' 3-form H in this paper

  12. Gravity and strings

    CERN Document Server

    Ortín, Tomás

    2015-01-01

    Self-contained and comprehensive, this definitive new edition of Gravity and Strings is a unique resource for graduate students and researchers in theoretical physics. From basic differential geometry through to the construction and study of black-hole and black-brane solutions in quantum gravity - via all the intermediate stages - this book provides a complete overview of the intersection of gravity, supergravity, and superstrings. Now fully revised, this second edition covers an extensive array of topics, including new material on non-linear electric-magnetic duality, the electric-tensor formalism, matter-coupled supergravity, supersymmetric solutions, the geometries of scalar manifolds appearing in 4- and 5-dimensional supergravities, and much more. Covering reviews of important solutions and numerous solution-generating techniques, and accompanied by an exhaustive index and bibliography, this is an exceptional reference work.

  13. On the Classical String Solutions and String/Field Theory Duality

    OpenAIRE

    Aleksandrova, D.; Bozhilov, P.

    2003-01-01

    We classify almost all classical string configurations, considered in the framework of the semi-classical limit of the string/gauge theory duality. Then, we describe a procedure for obtaining the conserved quantities and the exact classical string solutions in general string theory backgrounds, when the string embedding coordinates depend non-linearly on the worldsheet time parameter.

  14. String Formatting Considered Harmful for Novice Programmers

    Science.gov (United States)

    Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found…

  15. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    We present a detailed analysis of the motion of test particle in the gravitational field of cosmic strings in different situations using the Hamilton–Jacobi (H–J) formalism. We have discussed the trajectories near static cosmic string, cosmic string in Brans–Dicke theory and cosmic string in dilaton gravity.

  16. Interaction of cosmic strings with gravitational waves

    International Nuclear Information System (INIS)

    Frolov, V.P.; Garfinkle, D.

    1990-01-01

    We find solutions of Einstein's equation representing a gravitational wave interacting with a cosmic-string traveling wave. The motion of test cosmic strings in the gravitational field of a cosmic-string traveling wave is also examined. A solution representing traveling waves on several parallel cosmic strings is also found

  17. String matching with variable length gaps

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Vildhøj, Hjalte Wedel

    2012-01-01

    We consider string matching with variable length gaps. Given a string T and a pattern P consisting of strings separated by variable length gaps (arbitrary strings of length in a specified range), the problem is to find all ending positions of substrings in T that match P. This problem is a basic...

  18. Pulmonary vascular endothelium: the orchestra conductor in respiratory diseases: Highlights from basic research to therapy.

    Science.gov (United States)

    Huertas, Alice; Guignabert, Christophe; Barberà, Joan A; Bärtsch, Peter; Bhattacharya, Jahar; Bhattacharya, Sunita; Bonsignore, Maria R; Dewachter, Laurence; Dinh-Xuan, Anh Tuan; Dorfmüller, Peter; Gladwin, Mark T; Humbert, Marc; Kotsimbos, Tom; Vassilakopoulos, Theodoros; Sanchez, Olivier; Savale, Laurent; Testa, Ugo; Wilkins, Martin R

    2018-04-01

    The European Respiratory Society (ERS) Research Seminar entitled "Pulmonary vascular endothelium: orchestra conductor in respiratory diseases - highlights from basic research to therapy" brought together international experts in dysfunctional pulmonary endothelium, from basic science to translational medicine, to discuss several important aspects in acute and chronic lung diseases. This review will briefly sum up the different topics of discussion from this meeting which was held in Paris, France on October 27-28, 2016. It is important to consider that this paper does not address all aspects of endothelial dysfunction but focuses on specific themes such as: 1) the complex role of the pulmonary endothelium in orchestrating the host response in both health and disease (acute lung injury, chronic obstructive pulmonary disease, high-altitude pulmonary oedema and pulmonary hypertension); and 2) the potential value of dysfunctional pulmonary endothelium as a target for innovative therapies. Copyright ©ERS 2018.

  19. Geometry, topology, and string theory

    Energy Technology Data Exchange (ETDEWEB)

    Varadarajan, Uday [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.

  20. STRING v9.1

    DEFF Research Database (Denmark)

    Franceschini, A.; Simonovic, M.; Roth, A.

    2013-01-01

    data is desirable, including lower-quality data and/or computational predictions. The STRING database (http://string-db.org/) aims to provide such a global perspective for as many organisms as feasible. Known and predicted associations are scored and integrated, resulting in comprehensive protein...... networks covering >1100 organisms. Here, we describe the update to version 9.1 of STRING, introducing several improvements: (i) we extend the automated mining of scientific texts for interaction information, to now also include full-text articles; (ii) we entirely re-designed the algorithm for transferring...

  1. Spin chain for quantum strings

    International Nuclear Information System (INIS)

    Beisert, N.

    2005-01-01

    We review and compare the integrable structures in N=4 gauge theory and string theory on AdS 5 x S 5 . Recently, Bethe ansaetze for gauge theory/weak coupling and string theory/strong coupling were proposed to describe scaling dimensions in the su(2) subsector. Here we investigate the Bethe equations for quantum string theory, naively extrapolated to weak coupling. Excitingly, we find a spin chain Hamiltonian similar, but not equal, to the gauge theory dilatation operator. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  2. Covariant N-string amplitude

    International Nuclear Information System (INIS)

    Di Vecchia, P.; Sciuto, S.; Nakayama, R.; Petersen, J.L.; Sidenius, J.R.

    1986-11-01

    The BRST-invariant N-Reggeon vertex (for the bosonic string) previously given by us in the operator formulation is considered in more detail. In particular we present a direct derivation from the string path integral. Several crucial symmetry properties found a posteriori before, become a priori clearer in this formulation. A number of delicate points related to zero modes, cut off procedures and normal ordering prescriptions are treated in some detail. The old technique of letting the string field acquire a small dimension ε/2 → 0 + is found especially elegant. (orig.)

  3. Plucked Strings and the Harpsichord

    Science.gov (United States)

    GIORDANO, N.; WINANS, J. P.

    1999-07-01

    The excitation of a harpsichord string when it is set into motion, i.e., plucked, by a plectrum is studied. We find that the amplitude of the resulting string vibration is approximately independent of the velocity with which the key is depressed. This result is in accord with conventional wisdom, but at odds with a recent theoretical model. A more realistic theoretical treatment of the plucking process is then described, and shown to be consistent with our measurements. The experiments reveal several other interesting aspects of the plectrum-string interaction.

  4. Nonassociative gravity in string theory?

    Energy Technology Data Exchange (ETDEWEB)

    Blumenhagen, R [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany); Plauschinn, E, E-mail: ralph.blumenhagen@mpp.mpg.d, E-mail: e.plauschinn@uu.n [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)

    2011-01-07

    In an on-shell conformal field theory approach, we find indications of a three-bracket structure for target space coordinates in general closed string backgrounds. This generalizes the appearance of noncommutative gauge theories for open strings in two-form backgrounds to a putative noncommutative/nonassociative gravity theory for closed strings probing curved backgrounds with non-vanishing three-form flux. Several aspects and consequences of the three-bracket structure are discussed and a new type of generalized uncertainty principle is proposed.

  5. Geometry, topology, and string theory

    International Nuclear Information System (INIS)

    Varadarajan, Uday

    2003-01-01

    A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated

  6. M-strings, Elliptic Genera and N=4 String Amplitudes

    CERN Document Server

    Hohenegger, Stefan

    2014-01-01

    We study mass-deformed N=2 gauge theories from various points of view. Their partition functions can be computed via three dual approaches: firstly, (p,q)-brane webs in type II string theory using Nekrasov's instanton calculus, secondly, the (refined) topological string using the topological vertex formalism and thirdly, M theory via the elliptic genus of certain M-strings configurations. We argue for a large class of theories that these approaches yield the same gauge theory partition function which we study in detail. To make their modular properties more tangible, we consider a fourth approach by connecting the partition function to the equivariant elliptic genus of R^4 through a (singular) theta-transform. This form appears naturally as a specific class of one-loop scattering amplitudes in type II string theory on T^2, which we calculate explicitly.

  7. M-strings, elliptic genera and N = 4 string amplitudes

    International Nuclear Information System (INIS)

    Hohenegger, S.; Iqbal, A.

    2014-01-01

    We study mass-deformed N = 2 gauge theories from various points of view. Their partition functions can be computed via three dual approaches: firstly, (p,q)-brane webs in type II string theory using Nekrasov's instanton calculus, secondly, the (refined) topological string using the topological vertex formalism and thirdly, M theory via the elliptic genus of certain M-strings configurations. We argue for a large class of theories that these approaches yield the same gauge theory partition function which we study in detail. To make their modular properties more tangible, we consider a fourth approach by connecting the partition function to the equivariant elliptic genus of C 2 through a (singular) theta-transform. This form appears naturally as a specific class of one-loop scattering amplitudes in type II string theory on T 2 , which we calculate explicitly. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Prokofieff: Krieg und Frieden (Sinfonische Suite), Die Verlobung im Kloster (Sommernacht-Suite), Russische Overtüre. Philharmonia Orchestra, Neeme Järvi / G. W.

    Index Scriptorium Estoniae

    G. W.

    1993-01-01

    Uuest heliplaadist "Prokofieff: Krieg und Frieden (Sinfonische Suite), Die Verlobung im Kloster (Sommernacht-Suite), Russische Overtüre. Philharmonia Orchestra, Neeme Järvi. (AD: 1991). Chandos/Koch CD 9096

  9. Schmidt. Sinfonie Nr. 1 E-Dur; Strauss. Vier sinfonische Zwischenspiele aus Intermezzo. Detroit Symphony Orchestra, Neeme Järvi / Helge Grünewald

    Index Scriptorium Estoniae

    Grünewald, Helge

    1996-01-01

    Uuest heliplaadist "Schmidt. Sinfonie Nr. 1 E-Dur; Strauss. Vier sinfonische Zwischenspiele aus Intermezzo. Detroit Symphony Orchestra, Neeme Järvi. Chandos/Koch CD 9357 (WD: 68'20") DDD (WD:114'36")

  10. Sibelius: Pohjola's Daughter; Night Ride and Sunrise; Four Legends from Kalevala (Lemminkäinen Suite). Gothenburg Symphony Orchestra, Neeme Järvi / Brian Hunt

    Index Scriptorium Estoniae

    Hunt, Brian

    1997-01-01

    Uuest heliplaadist "Sibelius: Pohjola's Daughter; Night Ride and Sunrise; Four Legends from Kalevala (Lemminkäinen Suite). Gothenburg Symphony Orchestra / Neeme Järvi. Deutsche Grammophon 453 426-2; 70:37 DDD

  11. Charting the landscape of supercritical string theory.

    Science.gov (United States)

    Hellerman, Simeon; Swanson, Ian

    2007-10-26

    Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions and different amounts of world sheet supersymmetry. These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories.

  12. Charting the Landscape of Supercritical String Theory

    International Nuclear Information System (INIS)

    Hellerman, Simeon; Swanson, Ian

    2007-01-01

    Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions and different amounts of world sheet supersymmetry. These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories

  13. Matrix string theory on pp-waves

    Energy Technology Data Exchange (ETDEWEB)

    Bonelli, Giulio

    2003-06-21

    After a brief review on matrix string theory on flat backgrounds, we formulate matrix string models on different pp-wave backgrounds. This will be done both in the cases of constant and variable RR background flux for certain exact string geometries. We exhibit the non-perturbative representation of string interaction and show how the eigenvalue tunnelling drives the WKB expansion to give the usual perturbative string interaction also in supersymmetric pp-wave background cases.

  14. String theory and cosmological singularities

    Indian Academy of Sciences (India)

    time' can have a beginning or end. Well-known examples are singularities inside black holes and initial or final singularities in expanding or contracting universes. In recent times, string theory is providing new perspectives of such singularities ...

  15. Cache-oblivious string dictionaries

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf

    2006-01-01

    We present static cache-oblivious dictionary structures for strings which provide analogues of tries and suffix trees in the cache-oblivious model. Our construction takes as input either a set of strings to store, a single string for which all suffixes are to be stored, a trie, a compressed trie......, or a suffix tree, and creates a cache-oblivious data structure which performs prefix queries in O(logB n + |P|/B) I/Os, where n is the number of leaves in the trie, P is the query string, and B is the block size. This query cost is optimal for unbounded alphabets. The data structure uses linear space....

  16. String and Sticky Tape Experiments.

    Science.gov (United States)

    Edge, R. D., Ed.

    1979-01-01

    Explains how to demonstrate the fundamentals of one dimensional kinematics such as Newton's third law of motion, and collision between bodies, using simple materials of marbles, strings, sticky tape, drinking straws, and rubber bands. (GA)

  17. Spin chains and string theory.

    Science.gov (United States)

    Kruczenski, Martin

    2004-10-15

    Recently, an important test of the anti de Sitter/conformal field theory correspondence has been done using rotating strings with two angular momenta. We show that such a test can be described more generally as the agreement between two actions: one a low energy description of a spin chain appearing in the field theory side, and the other a limit of the string action in AdS5xS5. This gives a map between the mean value of the spin in the boundary theory and the position of the string in the bulk, and shows how a string action can emerge from a gauge theory in the large-N limit.

  18. Pattern recognition and string matching

    CERN Document Server

    Cheng, Xiuzhen

    2002-01-01

    The research and development of pattern recognition have proven to be of importance in science, technology, and human activity. Many useful concepts and tools from different disciplines have been employed in pattern recognition. Among them is string matching, which receives much theoretical and practical attention. String matching is also an important topic in combinatorial optimization. This book is devoted to recent advances in pattern recognition and string matching. It consists of twenty eight chapters written by different authors, addressing a broad range of topics such as those from classifica­ tion, matching, mining, feature selection, and applications. Each chapter is self-contained, and presents either novel methodological approaches or applications of existing theories and techniques. The aim, intent, and motivation for publishing this book is to pro­ vide a reference tool for the increasing number of readers who depend upon pattern recognition or string matching in some way. This includes student...

  19. String moduli inflation. An overview

    International Nuclear Information System (INIS)

    Cicoli, Michele; Quevedo, Fernando

    2011-06-01

    We present an overview of inflationary models derived from string theory focusing mostly on closed string moduli as inflatons. After a detailed discussion of the η-problem and different approaches to address it, we describe possible ways to obtain a de Sitter vacuum with all closed string moduli stabilised. We then look for inflationary directions and present some of the most promising scenarios where the inflatons are either the real or the imaginary part of Kaehler moduli. We pay particular attention on extracting potential observable implications, showing how most of the scenarios predict negligible gravitational waves and could therefore be ruled out by the Planck satellite. We conclude by briefly mentioning some open challenges in string cosmology beyond deriving just inflation. (orig.)

  20. String theory or field theory?

    International Nuclear Information System (INIS)

    Marshakov, A.V.

    2002-01-01

    The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are analyzed. This analysis helps better understand the role and place of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances. It is this task, the creation of such a theory, which string theory, currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments, which are our concern in this review [ru

  1. On Field Theory of Open Strings, Tachyon Condensation and Closed Strings

    OpenAIRE

    Shatashvili, Samson L.

    2001-01-01

    I review the physical properties of different vacua in the background independent open string field theory. Talk presented at Strings 2001, Mumbai, India, http://theory.theory.tifr.res.in/strings/Proceedings/#sha-s.

  2. Black strings and classical hair

    International Nuclear Information System (INIS)

    Horowitz, G.T.; Yang, H.

    1997-01-01

    We examine the geometry near the event horizon of a family of black string solutions with traveling waves. It has previously been shown that the metric is continuous there. Contrary to expectations, we find that the geometry is not smooth, and the horizon becomes singular whenever a wave is present. Both five-dimensional and six-dimensional black strings are considered with similar results. copyright 1997 The American Physical Society

  3. Strings in the abelized picture

    International Nuclear Information System (INIS)

    Embacher, F.

    1990-01-01

    The transformation properties of the bosonic string variables under the recently discovered abelizing operator are exhibited. The intimate relation of this operator to the light-cone gauge condition is illustrated for the classical string. As an application of the formalism, the derivation of the BRST cohomology by the method of Freeman and Olive is carried over to the abelized picture, where it takes a particulary simple form. 14 refs. (Author)

  4. Semiclassical Strings in Supergravity PFT

    OpenAIRE

    Banerjee, Aritra; Biswas, Sagar; Panigrahi, Kamal L.

    2014-01-01

    Puff field theory (PFT) is an example of a non-local field theory which arises from a novel embedding of D-branes in a Melvin universe. We study several rotating and pulsating string solutions of the F-string equations of motion in the supergravity dual of the PFT. Further, we find a PP-wave geometry from this non-local spacetime by applying a Penrose limit and comment on its similarity with the maximally supersymmetric PP-wave background.

  5. Dynamics of strings between walls

    International Nuclear Information System (INIS)

    Eto, Minoru; Fujimori, Toshiaki; Nagashima, Takayuki; Nitta, Muneto; Ohashi, Keisuke; Sakai, Norisuke

    2009-01-01

    Configurations of vortex strings stretched between or ending on domain walls were previously found to be 1/4 Bogomol'nyi-Prasad-Sommerfield (BPS) states in N=2 supersymmetric gauge theories in 3+1 dimensions. Among zero modes of string positions, the center of mass of strings in each region between two adjacent domain walls is shown to be non-normalizable whereas the rests are normalizable. We study dynamics of vortex strings stretched between separated domain walls by using two methods, the moduli space (geodesic) approximation of full 1/4 BPS states and the charged particle approximation for string end points in the wall effective action. In the first method we explicitly obtain the effective Lagrangian in the strong coupling limit, which is written in terms of hypergeometric functions, and find the 90 deg. scattering for head-on collision. In the second method the domain wall effective action is assumed to be U(1) N gauge theory, and we find a good agreement between two methods for well-separated strings.

  6. String theory on the edge

    International Nuclear Information System (INIS)

    Thorlacius, L.

    1989-01-01

    Open string vacuum configurations are described in terms of a one-dimensional field theory on the worldsheet boundary. The one-dimensional path integral has direct physical interpretation as a source term for closed string fields. This means that the vacuum divergences (Mobius infinities) of the path integral must be renormalized correctly. The author shows that reparametrization invariance Ward identities, apart from specifying the equations of motion of spacetime background gauge fields, also serve to fix the renormalization scheme of the vacuum divergences. He argues that vacuum configurations of open strings correspond to Caldeira-Leggett models of dissipative quantum mechanics (DQM) evaluated at a delocalization critical point. This connection reveals that critical DQM will manifest reparametrization invariance (inherited from the conformal invariance of string theory) rather than just scale invariance. This connection should open up new ways of constructing analytic and approximate solutions of open string theory (in particular, topological solitons such as monopoles and instantons). Type I superstring theory gives rise to a supersymmetric boundary field theory. Bose-Fermi cancellation eliminates vacuum divergences but the one-loop beta function remains the same as in the bosonic theory. Reparametrization invariance Ward identities dictate a boundary state normalization which yields consistent string-loop corrections to spacetime equations of motion, in both the periodic and anti-periodic fermion sectors

  7. Experimental observation of Bethe strings

    Science.gov (United States)

    Wang, Zhe; Wu, Jianda; Yang, Wang; Bera, Anup Kumar; Kamenskyi, Dmytro; Islam, A. T. M. Nazmul; Xu, Shenglong; Law, Joseph Matthew; Lake, Bella; Wu, Congjun; Loidl, Alois

    2018-02-01

    Almost a century ago, string states—complex bound states of magnetic excitations—were predicted to exist in one-dimensional quantum magnets. However, despite many theoretical studies, the experimental realization and identification of string states in a condensed-matter system have yet to be achieved. Here we use high-resolution terahertz spectroscopy to resolve string states in the antiferromagnetic Heisenberg-Ising chain SrCo2V2O8 in strong longitudinal magnetic fields. In the field-induced quantum-critical regime, we identify strings and fractional magnetic excitations that are accurately described by the Bethe ansatz. Close to quantum criticality, the string excitations govern the quantum spin dynamics, whereas the fractional excitations, which are dominant at low energies, reflect the antiferromagnetic quantum fluctuations. Today, Bethe’s result is important not only in the field of quantum magnetism but also more broadly, including in the study of cold atoms and in string theory; hence, we anticipate that our work will shed light on the study of complex many-body systems in general.

  8. Fast searching in packed strings

    DEFF Research Database (Denmark)

    Bille, Philip

    2011-01-01

    Given strings P and Q the (exact) string matching problem is to find all positions of substrings in Q matching P. The classical Knuth–Morris–Pratt algorithm [SIAM J. Comput. 6 (2) (1977) 323–350] solves the string matching problem in linear time which is optimal if we can only read one character...... at the time. However, most strings are stored in a computer in a packed representation with several characters in a single word, giving us the opportunity to read multiple characters simultaneously. In this paper we study the worst-case complexity of string matching on strings given in packed representation....... Let m⩽n be the lengths P and Q, respectively, and let σ denote the size of the alphabet. On a standard unit-cost word-RAM with logarithmic word size we present an algorithm using timeO(nlogσn+m+occ). Here occ is the number of occurrences of P in Q. For m=o(n) this improves the O(n) bound of the Knuth...

  9. Chern-Simons couplings for dielectric F-strings in matrix string theory

    International Nuclear Information System (INIS)

    Brecher, Dominic; Janssen, Bert; Lozano, Yolanda

    2002-01-01

    We compute the non-abelian couplings in the Chern-Simons action for a set of coinciding fundamental strings in both the type IIA and type IIB Matrix string theories. Starting from Matrix theory in a weakly curved background, we construct the linear couplings of closed string fields to type IIA Matrix strings. Further dualities give a type IIB Matrix string theory and a type IIA theory of Matrix strings with winding. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  10. New expressions for string loop amplitudes leading to an ultra-simple conception of string dynamics

    International Nuclear Information System (INIS)

    Chan Hongmo; Tsou Sheungtsun; Bordes, J.; Nellen, L.

    1990-11-01

    New expressions are derived for string loop amplitudes as overlap integrals of string wave functionals. They are shown to take the form of exchange terms coming from the Bose-Einstein symmetrisation between string segments. One is thus led to the ultra-simple conception that string theory is basically free, and that 'string interactions' are due merely to the fact that strings are composite objects with Bose-Einstein segments as constituents. (author)

  11. Tips in Reading Instruction.

    Science.gov (United States)

    Ediger, Marlow

    Some tips can assist teachers in guiding each pupil to achieve more optimally, with respect to the ability to read well and reading comprehension. Among these 10 specific tips are: (1) teach individualized phonics in context; (2) assist the student to read in proper thought units by covering up words in sentences for clarification; (3) assist…

  12. ADHD: Tips to Try

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español ADHD: Tips to Try KidsHealth / For Teens / ADHD: Tips to Try Print en español TDAH: Consejos que puedes probar ADHD , short for attention deficit hyperactivity disorder , is a ...

  13. Total Telephone Tips.

    Science.gov (United States)

    Corder, Lloyd E.; And Others

    This manual of telephone behavior tips for business and sales professionals offers ways to handle the disgruntled caller and makes suggestions on topics relevant to the telephone. The manual is divided into the following sections and subsections: (1) Common Courtesy (staff tips, answering the telephone, screening calls, transferring calls, taking…

  14. Gravity from strings

    International Nuclear Information System (INIS)

    Deser, S.

    1987-01-01

    We obtain the Einstein action plus quadratic curvature corrections generated by closed bosonic, heterotic and supersymmetric strings by matching the four-graviton amplitude (to first order in the slope parameter and fourth power of momenta) with an effective local gravitational action. The resulting corrections are first shown to be of the Gauss-Bonnet form. It is then noted that, by the very nature of the slope expansion, the field-redefinition theorem applies. Consequently, only the curvature-squared term is determined, while squares of its contractions are explicitly seen not to contribute. This latter property has a generalization to all orders which implies that the effective gravitational action is unavoidably ghost-free. The properties of solutions to these corrected theories are then examined. First neglecting dilatons, we find the explicit 'Schwarzschild' metrics. Both asymptotically flat and de Sitter solutions are present. The latter are however shown to be unstable. The former have horizons and singularities which are respectively smaller and less violent than in Einstein gravity; the correct sign of the slope parameter also ensures absence of naked singularities. When dilatons are included, the cosmological vacua are gratifyingly excluded. (orig.)

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the liver). Portal hypertension can also occur in children, although children are much less likely to require a TIPS. ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... vs. risks? What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A ... likely to require a TIPS. top of page What are some common uses of the procedure? A ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS ...

  18. Conformal supergravity in twistor-string theory

    Energy Technology Data Exchange (ETDEWEB)

    Berkovits, Nathan [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900, Sao Paulo, SP (Brazil)]. E-mail: nberkovi@ift.unesp.br; Witten, Edward [School of Natural Sciences, Institute for Advanced Study, Princeton NJ 08540 (United States)

    2004-08-01

    Conformal supergravity arises in presently known formulations of twistor-string theory either via closed strings or via gauge-singlet open strings. We explore this sector of twistor-string theory, relating the relevant string modes to the particles and fields of conformal supergravity. We use the twistor-string theory to compute some tree level scattering amplitudes with supergravitons. Since the supergravitons interact with the same coupling constant as the Yang-Mills fields, conformal supergravity states will contribute to loop amplitudes of Yang-Mills gluons in these theories. Those loop amplitudes will therefore not coincide with the loop amplitudes of pure super Yang-Mills theory. (author)

  19. Gravitational Lensing Signatures of Long Cosmic Strings

    CERN Document Server

    De Laix, A A; Vachaspati, T; Laix, Andrew A. de; Krauss, Lawrence M.; Vachaspati, Tanmay

    1997-01-01

    The gravitational lensing by long, wiggly cosmic strings is shown to produce a large number of lensed images of a background source. In addition to pairs of images on either side of the string, a number of small images outline the string due to small-scale structure on the string. This image pattern could provide a highly distinctive signature of cosmic strings. Since the optical depth for multiple imaging of distant quasar sources by long strings may be comparable to that by galaxies, these image patterns should be clearly observable in the next generation of redshift surveys such as the Sloan Digital Sky Survey.

  20. String Theory for Pedestrians (1/3)

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    This is a non-technical rapid course on string theory. Lecture 1 is an introduction to the basics of the subject: classical and quantum strings, D(irichlet) branes and string-string dualities. In lecture 2 I will discuss string unification of the fundamental forces, covering both its successes and failures. Finally in lecture 3 I will review string models of black hole microstates, the holographic gauge/gravity duality and, if time permits, potential applications to the physics of the strong interactions.

  1. String Theory for Pedestrians (2/3)

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    This is a non-technical rapid course on string theory. Lecture 1 is an introduction to the basics of the subject: classical and quantum strings, D(irichlet) branes and string-string dualities. In lecture 2 I will discuss string unification of the fundamental forces, covering both its successes and failures. Finally in lecture 3 I will review string models of black hole microstates, the holographic gauge/gravity duality and, if time permits, potential applications to the physics of the strong interactions.

  2. String Theory for Pedestrians (3/3)

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    This is a non-technical rapid course on string theory. Lecture 1 is an introduction to the basics of the subject: classical and quantum strings, D(irichlet) branes and string-string dualities. In lecture 2 I will discuss string unification of the fundamental forces, covering both its successes and failures. Finally in lecture 3 I will review string models of black hole microstates, the holographic gauge/gravity duality and, if time permits, potential applications to the physics of the strong interactions.

  3. Ureteric stent placement with extraction string: no strings attached?

    Science.gov (United States)

    Bockholt, Nathan A; Wild, Trevor T; Gupta, Amit; Tracy, Chad R

    2012-12-01

    Study Type--Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Of patients treated with an indwelling ureteric stent 80-90% experience lower urinary tract symptoms that are a hindrance to health-related quality of life. The prevalence of the extraction/retrieval string after ureteroscopy for stone disease and stent placement varies significantly between surgeons and published series, but the benefits of eliminating the need for a secondary procedure such as cystoscopy and stent removal, as well as the decrease in cost to the patient are well established. Published reports have not addressed the prevalence of post-procedure related events (PREs) in patients who have received an indwelling ureteric stent with the extraction/retrieval string still intact after ureteroscopy for stone disease. By analysing PREs (Emergency Room visits, unscheduled clinic visits, and telephone calls) related to their stent or procedure for patients with and without an extraction/retrieval string, the feasibility of the extraction string can be validated and the misconceptions about their use can be alleviated. • To review a retrospective ureteric stent cohort with and without extraction string to compare post-procedure related events (PRE), as ureteric stent placement after endoscopic management of urolithiasis is common, but data regarding the potential benefits or disadvantages of ureteric stent placement with extraction string are sparse. • Between June 2009 and June 2010, 293 patients underwent ureteroscopy with or without lithotripsy for stone disease. • In all, 181 patients had a unilateral procedure and underwent stent placement postoperatively. • Records were retrospectively reviewed for operative data and PRE occurring within the first 6 weeks after surgery, defined as unscheduled clinic or Emergency Room visits, or adverse event telephone calls. • Of 181 patients who underwent ureteric stent placement, 43 (23

  4. String Theory in a Nutshell

    International Nuclear Information System (INIS)

    Skenderis, Kostas

    2007-01-01

    The book 'String Theory in a Nutshell' by Elias Kiritsis provides a comprehensive introduction to modern string theory. String theory is the leading candidate for a theory that successfully unifies all fundamental forces of nature, including gravity. The subject has been continuously developing since the early 1970s, with classic textbooks on the subject being those of Green, Schwarz and Witten (1987) and Polchinski (1998). Since the latter was published there have been substantial developments, in particular in understanding black holes and gravity/gauge theory dualities. A textbook treatment of this important material is clearly needed, both by students and researchers in string theory and by mathematicians and physicists working in related fields. This book has a good selection of material, starting from basics and moving into classic and modern topics. In particular, Kiritsis' presentation of the basic material is complementary to that of the earlier textbooks and he includes a number of topics which are not easily found or covered adequately elsewhere, for example, loop corrections to string effective couplings. Overall the book nicely covers the major advances of the last ten years, including (non-perturbative) string dualities, black hole physics, AdS/CFT and matrix models. It provides a concise but fairly complete introduction to these subjects which can be used both by students and by researchers. Moreover the emphasis is on results that are reasonably established, as is appropriate for a textbook; concise summaries are given for subjects which are still in flux, with references to relevant reviews and papers. A positive feature of the book is that the bibliography sections at the end of each chapter provide a comprehensive guide to the literature. The bibliographies point to reviews and pedagogical papers on subjects covered in this book as well as those that were omitted. It is rare for a textbook to contain such a self-contained and detailed guide to

  5. String Theory in a Nutshell

    Energy Technology Data Exchange (ETDEWEB)

    Skenderis, Kostas [Institute of Theoretical Physics, Universiteit van Amsterdam, Valckenierstraat 65, NL-1018 XE Amsterdam (Netherlands)

    2007-11-21

    The book 'String Theory in a Nutshell' by Elias Kiritsis provides a comprehensive introduction to modern string theory. String theory is the leading candidate for a theory that successfully unifies all fundamental forces of nature, including gravity. The subject has been continuously developing since the early 1970s, with classic textbooks on the subject being those of Green, Schwarz and Witten (1987) and Polchinski (1998). Since the latter was published there have been substantial developments, in particular in understanding black holes and gravity/gauge theory dualities. A textbook treatment of this important material is clearly needed, both by students and researchers in string theory and by mathematicians and physicists working in related fields. This book has a good selection of material, starting from basics and moving into classic and modern topics. In particular, Kiritsis' presentation of the basic material is complementary to that of the earlier textbooks and he includes a number of topics which are not easily found or covered adequately elsewhere, for example, loop corrections to string effective couplings. Overall the book nicely covers the major advances of the last ten years, including (non-perturbative) string dualities, black hole physics, AdS/CFT and matrix models. It provides a concise but fairly complete introduction to these subjects which can be used both by students and by researchers. Moreover the emphasis is on results that are reasonably established, as is appropriate for a textbook; concise summaries are given for subjects which are still in flux, with references to relevant reviews and papers. A positive feature of the book is that the bibliography sections at the end of each chapter provide a comprehensive guide to the literature. The bibliographies point to reviews and pedagogical papers on subjects covered in this book as well as those that were omitted. It is rare for a textbook to contain such a self-contained and

  6. An exact bosonization rule for c = 1 noncritical string theory

    International Nuclear Information System (INIS)

    Ishibashi, Nobuyuki; Yamaguchi, Atsushi

    2007-01-01

    We construct a string field theory for c = 1 noncritical strings using the loop variables as the string field. We show how one can express the nonrelativistic free fermions which describes the theory, in terms of these string fields

  7. Topological strings from quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, Alba; Marino, Marcos [Geneve Univ. (Switzerland). Dept. de Physique Theorique et Section de Mathematique; Hatsuda, Yasuyuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group

    2014-12-15

    We propose a general correspondence which associates a non-perturbative quantum-mechanical operator to a toric Calabi-Yau manifold, and we conjecture an explicit formula for its spectral determinant in terms of an M-theoretic version of the topological string free energy. As a consequence, we derive an exact quantization condition for the operator spectrum, in terms of the vanishing of a generalized θ function. The perturbative part of this quantization condition is given by the Nekrasov-Shatashvili limit of the refined topological string, but there are non-perturbative corrections determined by the conventional topological string. We analyze in detail the cases of local P{sup 2}, local P{sup 1} x P{sup 1} and local F{sub 1}. In all these cases, the predictions for the spectrum agree with the existing numerical results. We also show explicitly that our conjectured spectral determinant leads to the correct spectral traces of the corresponding operators, which are closely related to topological string theory at orbifold points. Physically, our results provide a Fermi gas picture of topological strings on toric Calabi-Yau manifolds, which is fully non-perturbative and background independent. They also suggest the existence of an underlying theory of M2 branes behind this formulation. Mathematically, our results lead to precise, surprising conjectures relating the spectral theory of functional difference operators to enumerative geometry.

  8. Towards optimal packed string matching

    DEFF Research Database (Denmark)

    Ben-Kiki, Oren; Bille, Philip; Breslauer, Dany

    2014-01-01

    In the packed string matching problem, it is assumed that each machine word can accommodate up to α characters, thus an n-character string occupies n/α memory words.(a) We extend the Crochemore–Perrin constant-space O(n)-time string-matching algorithm to run in optimal O(n/α) time and even in real......-time, achieving a factor α speedup over traditional algorithms that examine each character individually. Our macro-level algorithm only uses the standard AC0 instructions of the word-RAM model (i.e. no integer multiplication) plus two specialized micro-level AC0 word-size packed-string instructions. The main word...... matching work.(b) We also consider the complexity of the packed string matching problem in the classical word-RAM model in the absence of the specialized micro-level instructions wssm and wslm. We propose micro-level algorithms for the theoretically efficient emulation using parallel algorithms techniques...

  9. Differential geometry in string models

    International Nuclear Information System (INIS)

    Alvarez, O.

    1986-01-01

    In this article the author reviews the differential geometric approach to the quantization of strings. A seminal paper demonstrates the connection between the trace anomaly and the critical dimension. The role played by the Faddeev-Popov ghosts has been instrumental in much of the subsequent work on the quantization of strings. This paper discusses the differential geometry of two dimensional surfaces and its importance in the quantization of strings. The path integral quantization approach to strings will be carefully analyzed to determine the correct effective measure for string theories. The choice of measure for the path integral is determined by differential geometric considerations. Once the measure is determined, the manifest diffeomorphism invariance of the theory will have to be broken by using the Faddeev-Popov ansatz. The gauge fixed theory is studied in detail with emphasis on the role of conformal and gravitational anomalies. In the analysis, the path integral formulation of the gauge fixed theory requires summing over all the distinct complex structures on the manifold

  10. Topological strings from quantum mechanics

    International Nuclear Information System (INIS)

    Grassi, Alba; Marino, Marcos; Hatsuda, Yasuyuki

    2014-12-01

    We propose a general correspondence which associates a non-perturbative quantum-mechanical operator to a toric Calabi-Yau manifold, and we conjecture an explicit formula for its spectral determinant in terms of an M-theoretic version of the topological string free energy. As a consequence, we derive an exact quantization condition for the operator spectrum, in terms of the vanishing of a generalized θ function. The perturbative part of this quantization condition is given by the Nekrasov-Shatashvili limit of the refined topological string, but there are non-perturbative corrections determined by the conventional topological string. We analyze in detail the cases of local P 2 , local P 1 x P 1 and local F 1 . In all these cases, the predictions for the spectrum agree with the existing numerical results. We also show explicitly that our conjectured spectral determinant leads to the correct spectral traces of the corresponding operators, which are closely related to topological string theory at orbifold points. Physically, our results provide a Fermi gas picture of topological strings on toric Calabi-Yau manifolds, which is fully non-perturbative and background independent. They also suggest the existence of an underlying theory of M2 branes behind this formulation. Mathematically, our results lead to precise, surprising conjectures relating the spectral theory of functional difference operators to enumerative geometry.

  11. String theory or field theory?

    International Nuclear Information System (INIS)

    Marshakov, Andrei V

    2002-01-01

    The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are analyzed. This analysis helps better understand the role and place of string theory in the modern picture of the physical world. Even though quantum field theory describes a wide range of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances. It is this task, the creation of such a theory, which string theory, currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments which are our concern in this review. (reviews of topical problems)

  12. String Resonances at Hadron Colliders

    CERN Document Server

    Anchordoqui, Luis A; Dai, De-Chang; Feng, Wan-Zhe; Goldberg, Haim; Huang, Xing; Lust, Dieter; Stojkovic, Dejan; Taylor, Tomasz R

    2014-01-01

    [Abridged] We consider extensions of the standard model based on open strings ending on D-branes. Assuming that the fundamental string mass scale M_s is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (3000 fb^{-1}) with \\sqrt{s} = 14 TeV, and at potential future pp colliders, HE-LHC and VLHC, operating at \\sqrt{s} = 33 and 100 TeV, respectively. In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and \\gamma + jet are completely independent of the details of compactification, and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV), lowest massive Regge exc...

  13. First Aid Tips

    Science.gov (United States)

    ... Program Diversity In Vision Research & Ophthalmology (DIVRO) Student Training Programs To search for current job openings visit HHS USAJobs Home » NEI for Kids » First Aid Tips Listen All About Vision About the Eye ...

  14. Tips for Daily Life

    Science.gov (United States)

    ... chapter Join our online community Tips for Daily Life Coping skills will help you handle day-to- ... challenges, maximize your independence and live a meaningful life with your diagnosis. Accepting changes Creating a coping ...

  15. Toilet training tips

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000944.htm Toilet training tips To use the sharing features on ... and 'pee'. Teaching Your Child to Use the Toilet Once your child is comfortable sitting on the ...

  16. Black strings ending on horizons

    Science.gov (United States)

    Haddad, Nidal

    2012-12-01

    We construct an approximate static gravitational solution of the Einstein equations, with negative cosmological constant, describing a test black string stretching from the boundary of the Schwarzschild-AdS5 black brane toward the horizon. The construction builds on a derivative expansion method, assuming that the black brane metric changes slowly along the black string direction. We provide a solution up to second order in derivatives, and it implies, in particular, that the black string must shrink to zero size at the horizon of the black brane. In the near-horizon region of the black brane, where the two horizons intersect, we provide an exact solution of a cone that describes two intersecting horizons at different temperatures. Moreover, we show that this solution equally describes a thin and long black droplet.

  17. Cooperative strings and glassy interfaces.

    Science.gov (United States)

    Salez, Thomas; Salez, Justin; Dalnoki-Veress, Kari; Raphaël, Elie; Forrest, James A

    2015-07-07

    We introduce a minimal theory of glass formation based on the ideas of molecular crowding and resultant string-like cooperative rearrangement, and address the effects of free interfaces. In the bulk case, we obtain a scaling expression for the number of particles taking part in cooperative strings, and we recover the Adam-Gibbs description of glassy dynamics. Then, by including thermal dilatation, the Vogel-Fulcher-Tammann relation is derived. Moreover, the random and string-like characters of the cooperative rearrangement allow us to predict a temperature-dependent expression for the cooperative length ξ of bulk relaxation. Finally, we explore the influence of sample boundaries when the system size becomes comparable to ξ. The theory is in agreement with measurements of the glass-transition temperature of thin polymer films, and allows quantification of the temperature-dependent thickness hm of the interfacial mobile layer.

  18. Quantum Inhomogeneities in String Cosmology

    CERN Document Server

    Buonanno, A; Ungarelli, C; Veneziano, Gabriele

    1998-01-01

    Within two specific string cosmology scenarios --differing in the way the pre- and post-big bang phases are joined-- we compute the size and spectral slope of various types of cosmologically amplified quantum fluctuations that arise in generic compactifications of heterotic string theory. By further imposing that these perturbations become the dominant source of energy at the onset of the radiation era, we obtain physical bounds on the background's moduli, and discuss the conditions under which both a (quasi-) scale-invariant spectrum of axionic perturbations and sufficiently large seeds for the galactic magnetic fields are generated. We also point out a potential problem with achieving the exit to the radiation era when the string coupling is near its present value.

  19. Vector superconductivity in cosmic strings

    International Nuclear Information System (INIS)

    Dvali, G.R.; Mahajan, S.M.

    1992-03-01

    We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

  20. The STRING database in 2011

    DEFF Research Database (Denmark)

    Szklarczyk, Damian; Franceschini, Andrea; Kuhn, Michael

    2011-01-01

    and computational prediction techniques. However, public efforts to collect and present protein interaction information have struggled to keep up with the pace of interaction discovery, partly because protein-protein interaction information can be error-prone and require considerable effort to annotate. Here, we...... present an update on the online database resource Search Tool for the Retrieval of Interacting Genes (STRING); it provides uniquely comprehensive coverage and ease of access to both experimental as well as predicted interaction information. Interactions in STRING are provided with a confidence score......, and accessory information such as protein domains and 3D structures is made available, all within a stable and consistent identifier space. New features in STRING include an interactive network viewer that can cluster networks on demand, updated on-screen previews of structural information including homology...

  1. General relativity, strings, and mathematical physics

    CERN Document Server

    Porrati, Massimo

    1999-01-01

    We give a historical review of some aspects of string theory relevant to our present understanding of general relativity, and connected with Einstein's unification program. We also point out to various mathematical fallouts of $9 string theory. (31 refs).

  2. On the string equation at c=1

    International Nuclear Information System (INIS)

    Nakatsu, Toshio.

    1994-07-01

    The analogue of the string equation which specifies the partition function of c=1 string with a compactification radius β is an element of Z ≥1 is described in the framework of Toda lattice hierarchy. (author)

  3. Social transformation of two students in an El Sistema-inspired orchestra program

    Directory of Open Access Journals (Sweden)

    Christine D’Alexander

    2016-07-01

    Full Text Available In recent years there has been a substantial increase in El Sistema-inspired programs for young musicians. An overwhelming majority of these programs across the USA are centered in underserved communities where access to instrumental music training would otherwise be sparse. Most often, this is due to budget cuts partially or completely being wiped off from school curricula, or the financial cost associated with instrumental lessons. These programs, often free of cost to families, consist of musical training several days a week in small and large group classes, and claim to promote social change amongst these children’s lives. It is of importance to carefully study if, and how, these young musicians believe their lives are transforming through participation in these El Sistema-inspired programs, and if in fact, social change is occurring. This article reports on a multiple case study which sought to dive deeper into the lives of two children taking part in one El Sistema-inspired orchestral program located in Los Angeles, California. The study focused on the influence and impact this program has had on the lives of students, the exploration and formation of their beliefs surrounding musical learning, as well as experiences they share both as individuals and members of the orchestra.

  4. Concert halls with strong and lateral sound increase the emotional impact of orchestra music.

    Science.gov (United States)

    Pätynen, Jukka; Lokki, Tapio

    2016-03-01

    An audience's auditory experience during a thrilling and emotive live symphony concert is an intertwined combination of the music and the acoustic response of the concert hall. Music in itself is known to elicit emotional pleasure, and at best, listening to music may evoke concrete psychophysiological responses. Certain concert halls have gained a reputation for superior acoustics, but despite the continuous research by a multitude of objective and subjective studies on room acoustics, the fundamental reason for the appreciation of some concert halls remains elusive. This study demonstrates that room acoustic effects contribute to the overall emotional experience of a musical performance. In two listening tests, the subjects listen to identical orchestra performances rendered in the acoustics of several concert halls. The emotional excitation during listening is measured in the first experiment, and in the second test, the subjects assess the experienced subjective impact by paired comparisons. The results showed that the sound of some traditional rectangular halls provides greater psychophysiological responses and subjective impact. These findings provide a quintessential explanation for these halls' success and reveal the overall significance of room acoustics for emotional experience in music performance.

  5. Introduction to field theory of strings

    International Nuclear Information System (INIS)

    Kikkawa, K.

    1987-01-01

    The field theory of bosonic string is reviewed. First, theory is treated in a light-cone gauge. After a brief survey of the first quantized theory of free string, the second quantization is discussed. All possible interactions of strings are introduced based on a smoothness condition of work sheets swept out by strings. Perturbation theory is developed. Finally a possible way to the manifest covariant formalism is discussed

  6. The STRING database in 2017

    DEFF Research Database (Denmark)

    Szklarczyk, Damian; Morris, John H; Cook, Helen

    2017-01-01

    A system-wide understanding of cellular function requires knowledge of all functional interactions between the expressed proteins. The STRING database aims to collect and integrate this information, by consolidating known and predicted protein-protein association data for a large number of organi......A system-wide understanding of cellular function requires knowledge of all functional interactions between the expressed proteins. The STRING database aims to collect and integrate this information, by consolidating known and predicted protein-protein association data for a large number...

  7. Semiclassical strings in supergravity PFT

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Aritra; Biswas, Sagar; Panigrahi, Kamal L. [Indian Institute of Technology Kharagpur, Department of Physics, Kharagpur (India)

    2014-10-15

    Puff field theory (PFT) is an example of a non-local field theory which arises from a novel embedding of D-branes in a Melvin universe. We study several rotating and pulsating string solutions of the F-string equations of motion in the supergravity dual of the PFT. Further, we find a PP-wave geometry from this non-local spacetime by applying a Penrose limit and comment on its similarity with the maximally supersymmetric PP-wave background. (orig.)

  8. Cosmic string in gravity's rainbow

    Science.gov (United States)

    Momeni, Davood; Upadhyay, Sudhaker; Myrzakulov, Yerlan; Myrzakulov, Ratbay

    2017-09-01

    In this paper, we study the various cylindrical solutions (cosmic strings) in gravity's rainbow scenario. In particular, we calculate the gravitational field equations corresponding to energy-dependent background. Further, we discuss the possible Kasner, quasi-Kasner and non-Kasner exact solutions of the field equations. In this framework, we find that quasi-Kasner solutions cannot be realized in gravity's rainbow. Assuming only time-dependent metric functions, we also analyse the time-dependent vacuum cosmic strings in gravity's rainbow, which are completely different than the other GR solutions.

  9. The Physics of "String Passing through Ice"

    Science.gov (United States)

    Mohazzabi, Pirooz

    2011-01-01

    One of the oldest yet interesting experiments related to heat and thermodynamics is placing a string on a block of ice and hanging two masses from the ends of the string. Sometime later, it is discovered that the string has passed through the ice without cutting it in half. A simple explanation of this effect is that the pressure caused by the…

  10. The Illusive Sound of a Bundengan String

    Science.gov (United States)

    Parikesit, Gea O. F.; Kusumaningtyas, Indraswari

    2017-01-01

    The acoustics of a vibrating string is frequently used as a simple example of how physics can be applied in the field of art. In this paper we describe a simple experiment and analysis using a clipped string. This experiment can generate scientific curiosity among students because the sound generated by the string seem surprising to our senses.…

  11. How Do String Majors Become Teachers?

    Science.gov (United States)

    Ha, Joy

    2015-01-01

    This study was motivated by the desire to understand how to support the development of competent and confident string instrument teachers. This research investigates early-career string instrument teachers' experiences of pre-service tertiary education and induction, and how these experiences impacted early-career string teachers' competence to…

  12. String solitons and T-duality

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Riccioni, Fabio

    We construct for arbitrary dimensions a universal T-duality covariant expression for the Wess-Zumino terms of supersymmetric String Solitons in toroidally compactified string theories with 32 supercharges. The worldvolume fields occurring in the effective action of these String Solitons form either

  13. Symmetries and Interactions in Matrix String Theory

    NARCIS (Netherlands)

    Hacquebord, F.H.

    1999-01-01

    This PhD-thesis reviews matrix string theory and recent developments therein. The emphasis is put on symmetries, interactions and scattering processes in the matrix model. We start with an introduction to matrix string theory and a review of the orbifold model that flows out of matrix string theory

  14. Glueballs as rotating folded closed strings

    Science.gov (United States)

    Sonnenschein, Jacob; Weissman, Dorin

    2015-12-01

    In previous papers [1, 2] we argued that mesons and baryons can be described as rotating open strings in holographic backgrounds. Now we turn to closed strings, which should be the duals of glueballs. We look at the rotating folded closed string in both flat and curved backgrounds.

  15. Are Stopped Strings Preferred in Sad Music?

    Directory of Open Access Journals (Sweden)

    David Huron

    2017-01-01

    Full Text Available String instruments may be played either with open strings (where the string vibrates between the bridge and a hard wooden nut or with stopped strings (where the string vibrates between the bridge and a performer's finger pressed against the fingerboard. Compared with open strings, stopped strings permit the use of vibrato and exhibit a darker timbre. Inspired by research on the timbre of sad speech, we test whether there is a tendency to use stopped strings in nominally sad music. Specifically, we compare the proportion of potentially open-to-stopped strings in a sample of slow, minor-mode movements with matched major-mode movements. By way of illustration, a preliminary analysis of Samuel Barber's famous Adagio from his Opus 11 string quartet shows that the selected key (B-flat minor provides the optimum key for minimizing open string tones. However, examination of a broader controlled sample of quartet movements by Haydn, Mozart and Beethoven failed to exhibit the conjectured relationship. Instead, major-mode movements were found to avoid possible open strings more than slow minor-mode movements.

  16. Open bosonic string in background electromagnetic field

    International Nuclear Information System (INIS)

    Nesterenko, V.V.

    1987-01-01

    The classical and quantum dynamics of an open string propagating in the D-dimensional space-time in the presence of a background electromagnetic field is investigated. An important point in this consideration is the use of the generalized light-like gauge. There are considered the strings of two types; the neutral strings with charges at their ends obeying the condition q 1 +q 2 =0 and the charged strings having a net charge q 1 +q 2 ≠ 0. The consistency of theory demands that the background electric field does not exceed its critical value. The distance between the mass levels of the neutral open string decreases (1-e 2 ) times in comparison with the free string, where e is the dimensionless strength of the electric field. The magnetic field does not affect this distance. It is shown that at a classical level the squared mass of the neutral open string has a tachyonic contribution due to the motion of the string as a whole in transverse directions. The tachyonic term disappears if one considers, instead of M 2 , the string energy in a special reference frame where the projection of the total canonical momentum of the string onto the electric field vanishes. The contributions due to zero point fluctuations to the energy spectrum of the neutral string and to the Virasoro operators in the theory of charged string are found

  17. String duality and novel theories without gravity

    International Nuclear Information System (INIS)

    Kachru, Shamit

    1998-01-01

    We describe some of the novel 6d quantum field theories which have been discovered in studies of string duality. The role these theories (and their 4d descendants) may play in alleviating the vacuum degeneracy problem in string theory is reviewed. The DLCQ of these field theories is presented as one concrete way of formulating them, independent of string theory

  18. Transverse structure of the QCD string

    International Nuclear Information System (INIS)

    Meyer, Harvey B.

    2010-01-01

    The characterization of the transverse structure of the QCD string is discussed. We formulate a conjecture as to how the stress-energy tensor of the underlying gauge theory couples to the string degrees of freedom. A consequence of the conjecture is that the energy density and the longitudinal-stress operators measure the distribution of the transverse position of the string, to leading order in the string fluctuations, whereas the transverse-stress operator does not. We interpret recent numerical measurements of the transverse size of the confining string and show that the difference of the energy and longitudinal-stress operators is a particularly natural probe at next-to-leading order. Second, we derive the constraints imposed by open-closed string duality on the transverse structure of the string. We show that a total of three independent ''gravitational'' form factors characterize the transverse profile of the closed string, and obtain the interpretation of recent effective string theory calculations: the square radius of a closed string of length β defined from the slope of its gravitational form factor, is given by (d-1/2πσ)log(β/4r 0 ) in d space dimensions. This is to be compared with the well-known result that the width of the open string at midpoint grows as (d-1/2πσ)log(r/r 0 ). We also obtain predictions for transition form factors among closed-string states.

  19. Architectures and representations for string transduction

    NARCIS (Netherlands)

    Chrupala, Grzegorz

    2015-01-01

    String transduction problems are ubiquitous in natural language processing: they include transliteration, grapheme-to-phoneme conversion, text normalization and translation. String transduction can be reduced to the simpler problems of sequence labeling by expressing the target string as a sequence

  20. The issue of supersymmetry breaking in strings

    International Nuclear Information System (INIS)

    Binetruy, P.

    1989-12-01

    We discuss the central role that supersymmetry plays in string models, both in spacetime and at the level of the string world-sheet. The problems associated with supersymmetry-breaking are reviewed together with some of the attempts to solve them, in the string as well as the field theory approach

  1. General relativity invariance and string field theory

    International Nuclear Information System (INIS)

    Aref'eva, I.Ya.; Volovich, I.V.

    1987-04-01

    The general covariance principle in the string field theory is considered. The algebraic properties of the string Lie derivative are discussed. The string vielbein and spin connection are introduced and an action invariant under general co-ordinate transformation is proposed. (author). 18 refs

  2. String loop divergences and effective lagrangians

    International Nuclear Information System (INIS)

    Fischler, W.; Klebanov, I.; Susskind, L.

    1988-01-01

    We isolate logarithmic divergences from bosonic string amplitudes on a disc. These divergences are compared with 'tadpole' divergences in the effective field theory, with a covariant cosmological term implied by the counting of string coupling constants. We find an inconsistency between the two. This might be a problem in eliminating divergences from the bosonic string. (orig.)

  3. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    Gauge strings have their energy concentrated in a very thin tube, the radius of which is of the order of the symmetry- breaking scale whereas the global strings are such that their energy extends to regions far beyond the central core. Strings have an important astrophysical consequence, namely, the double quasar problem ...

  4. Introduction to the theory of strings

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1985-10-01

    These lectures present, from an introductory perspective, some basic aspects of the quantum theory of strings. They treat (1) the kinematics, spectrum, and scattering amplitude of the bosonic string, (2) the spectrum and supersymmetry of Green-Schwarz superstring, and (3) the identification of the underlying gauge invariances of the string theory. 43 refs

  5. String Theory, Strongly Correlated Systems, and Duality Twists

    Science.gov (United States)

    Torres Chicon, Nesty Ray

    In the first part of this dissertation (Chapter 1), I present a construction of a six dimensional (2,0)-theory model that describes the dynamics of the Fractional Quantum Hall Effect (FQHE). The FQHE appears as part of the low energy description of the Coulomb branch of the A1 (2,0)-theory formulated on a geometry (S 1 x R2)/Zk. At low-energy, the configuration is described in terms of a 4+1D supersymmetric Yang-Mills (SYM) theory on a cone (R2/Z k) with additional 2+1D degrees of freedom at the tip of the cone that include fractionally charged particles. These fractionally charged "quasi-particles" are BPS strings of the (2,0)-theory wrapped on short cycles. In this framework, a W-boson can be modeled as a bound state of k quasi-particles, which can be used to understand the dynamics of the FQHE. In the second part of this dissertation (Chapters 2-3), I investigate the N=4 SYM theory compactified on a circle, with a varying coupling constant (Janus configuration) and an S-duality twist. I relate this setup to a three dimensional topological theory and to a dual string theory. The equality of these descriptions is exhibited by matching the operator algebra, and the dimensions of the Hilbert space. Additionally, this dissertation addresses a classic result in number theory, called quadratic reciprocity, using string theory language. I present a proof that quadratic reciprocity is a direct consequence of T-duality of Type-II string theory. This is demonstrated by analyzing a partition function of abelian N=4 SYM theory on a certain supersymmetry-preserving four-manifold with variable coupling constant and a SL(2,Z)-duality twist.

  6. Bianchi type I string cosmologies

    Indian Academy of Sciences (India)

    By making use of Letelier's form of energy–momentum tensor for a cloud of stringdust we present some classes of solutions of general relativistic field equations which describe cosmological string-dust models in Bianchi type I space-time. Some of the classes of models obey Takabayashi's equation of state whereas a class ...

  7. Defect branes as Alice strings

    International Nuclear Information System (INIS)

    Okada, Takashi; Sakatani, Yuho

    2015-01-01

    There exist various defect-brane backgrounds in supergravity theories which arise as the low energy limit of string theories. These backgrounds typically have non-trivial monodromies, and if we move a charged probe around the center of a defect, its charge will be changed by the action of the monodromy. During the process, the charge conservation law seems to be violated. In this paper, to resolve this puzzle, we examine a dynamics of the charge changing process and show that the missing charge of the probe is transferred to the background. We then explicitly construct the resultant background after the charge transfer process by utilizing dualities. This background has the same monodromy as the original defect brane, but has an additional charge which does not have any localized source. In the literature, such a charge without localized source is known to appear in the presence of Alice strings. We argue that defect branes can in fact be regarded as a realization of Alice strings in string theory and examine the charge transfer process from that perspective.

  8. String formation beyond leading colour

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, Jesper R. [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14, Lund (Sweden); Theoretical Physics, CERN,CH-1211, Geneva 23 (Switzerland); Skands, Peter Z. [Theoretical Physics, CERN,CH-1211, Geneva 23 (Switzerland); School of Physics and Astronomy, Monash University,VIC-3800 (Australia)

    2015-08-03

    We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N{sub C} are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for “baryonic” configurations (e.g., two colours can combine coherently to form an anticolour). In e{sup +}e{sup −}collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/N{sub C}{sup 2} suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important 〈p{sub ⊥}〉(n{sub charged}) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p{sub ⊥} spectra remains challenging to explain.

  9. Monads, strings, and M theory

    NARCIS (Netherlands)

    Hofman, C.; Park, J.-S.

    1997-01-01

    The recent developmen ts in string theory suggest that the space-time coordinates should be generalized to non-comm uting matrices. P ostulating this suggestion as the fun- damen tal geometrical principle, w e form ulate a candidate for covariant second quantized RNS superstrings as a topological

  10. Topological strings and quantum curves

    NARCIS (Netherlands)

    Hollands, L.

    2009-01-01

    This thesis presents several new insights on the interface between mathematics and theoretical physics, with a central role for Riemann surfaces. First of all, the duality between Vafa-Witten theory and WZW models is embedded in string theory. Secondly, this model is generalized to a web of

  11. String theory and cosmological singularities

    Indian Academy of Sciences (India)

    Well-known examples are singularities inside black holes and initial or final singularities in expanding or contracting universes. In recent times, string theory is providing new perspectives of such singularities which may lead to an understanding of these in the standard framework of time evolution in quantum mechanics.

  12. Probing the string winding sector

    Energy Technology Data Exchange (ETDEWEB)

    Aldazabal, Gerardo; Mayo, Martín [G. Física CAB-CNEA and CONICET, Centro Atómico Bariloche,Av. Bustillo 9500, Bariloche (Argentina); Instituto Balseiro, Centro Atómico Bariloche,Av. Bustillo 9500, Bariloche (Argentina); Nuñez, Carmen [Instituto de Astronomía y Física del Espacio (CONICET-UBA),C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)

    2017-03-17

    We probe a slice of the massive winding sector of bosonic string theory from toroidal compactifications of Double Field Theory (DFT). This string subsector corresponds to states containing one left and one right moving oscillators. We perform a generalized Kaluza Klein compactification of DFT on generic 2n-dimensional toroidal constant backgrounds and show that, up to third order in fluctuations, the theory coincides with the corresponding effective theory of the bosonic string compactified on n-dimensional toroidal constant backgrounds, obtained from three-point amplitudes. The comparison between both theories is facilitated by noticing that generalized diffeomorphisms in DFT allow to fix generalized harmonic gauge conditions that help in identifying the physical degrees of freedom. These conditions manifest as conformal anomaly cancellation requirements on the string theory side. The explicit expression for the gauge invariant effective action containing the physical massless sector (gravity+antisymmetric+gauge+ scalar fields) coupled to towers of generalized Kaluza Klein massive states (corresponding to compact momentum and winding modes) is found. The action acquires a very compact form when written in terms of fields carrying O(n,n) indices, and is explicitly T-duality invariant. The global algebra associated to the generalized Kaluza Klein compactification is discussed.

  13. Genus g temperature string theory

    International Nuclear Information System (INIS)

    Murphy, P.; Sen, S.

    1989-01-01

    The geometric approach to bosonic temperature string theory for genus g is formulated in the operator approach of Vafa. It is shown that the Hagedorn temperature exists for all genus g and a conjectured genus g expression for superstring theories with temperature is constructed. (orig.)

  14. The Science of String Instruments

    CERN Document Server

    Rossing, Thomas D

    2010-01-01

    Many performing musicians, as well as instrument builders, are coming to realize the importance of understanding the science of musical instruments. This book explains how string instruments produce sound. It presents basic ideas in simple language, and it also translates some more sophisticated ideas in non-technical language. It should be of interest to performers, researchers, and instrument makers alike.

  15. String theory in the bathtub

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The presence of the surrounding medium makes their dynamics dramatically different from those of ordinary string-like objects propagating in empty space, leading to quite peculiar phenomena, observed in experiments and simulations. I will argue that the effective theory provides an optimal theoretical framework to understand such phenomena, and to make precise quantitative predictions about them.

  16. Strings, fields and critical phenomena

    International Nuclear Information System (INIS)

    Ambjoern, J.

    1987-07-01

    The connection between field theory and critical phenomena is reviewed. Emphasis is put on the use of Monte Carlo methods in the study of non-perturbative aspects of field theory. String theory is then described as a statistical theory of random surfaces and the critical behaviour is analyzed both by analytical and numerical methods. (orig.)

  17. Modified Steiner functional string action

    International Nuclear Information System (INIS)

    Baillie, C.F.; Johnston, D.A.

    1992-01-01

    It has recently been suggested by Ambartzumian et al. that the modified Steiner functional has desirable properties as an action for random surfaces and hence string world sheets. We perform a simulation of this action on a dynamically triangulated random surface to investigate this claim and find that the surfaces are in a flat phase

  18. Bianchi type I string cosmologies

    Indian Academy of Sciences (India)

    if a proper initial condition, viz., inflation is imposed on the very early universe. Various types of inflationary cosmologies are being considered and the string cosmology is one. It is generally believed that the very early universe underwent phase transitions, which gave rise to topologically stable structures; of particular ...

  19. Topological Strings and Integrable Hierarchies

    CERN Document Server

    Aganagic, M; Klemm, A D; Marino, M; Vafa, C; Aganagic, Mina; Dijkgraaf, Robbert; Klemm, Albrecht; Marino, Marcos; Vafa, Cumrun

    2006-01-01

    We consider the topological B-model on local Calabi-Yau geometries. We show how one can solve for the amplitudes by using W-algebra symmetries which encodes the symmetries of holomorphic diffeomorphisms of the Calabi-Yau. In the highly effective fermionic/brane formulation this leads to a free fermion description of the amplitudes. Furthermore we argue that topological strings on Calabi-Yau geometries provide a unifying picture connecting non-critical (super)strings, integrable hierarchies, and various matrix models. In particular we show how the ordinary matrix model, the double scaling limit of matrix models, and Kontsevich-like matrix model are all related and arise from studying branes in specific local Calabi-Yau three-folds. We also show how A-model topological string on P^1 and local toric threefolds (and in particular the topological vertex) can be realized and solved as B-model topological string amplitudes on a Calabi-Yau manifold.

  20. Ultrasensitive string-based temperature sensors

    DEFF Research Database (Denmark)

    Larsen, Tom; Schmid, Silvan; Gronberg, L.

    2011-01-01

    microstrings was measured. The relative change in resonant frequency per temperature change of -1.74 +/- 0.04%/ degrees C of the aluminum strings is more than one order of magnitude higher than of the silicon nitride strings and of comparable state-of-the-art AuPd strings.......Resonant strings are a promising concept for ultra sensitive temperature detection. We present an analytical model for the sensitivity with which we optimize the temperature response of resonant strings by varying geometry and material. The temperature sensitivity of silicon nitride and aluminum...

  1. String Theory and M-Theory

    Science.gov (United States)

    Becker, Katrin; Becker, Melanie; Schwarz, John H.

    String theory is one of the most exciting and challenging areas of modern theoretical physics. This book guides the reader from the basics of string theory to recent developments. It introduces the basics of perturbative string theory, world-sheet supersymmetry, space-time supersymmetry, conformal field theory and the heterotic string, before describing modern developments, including D-branes, string dualities and M-theory. It then covers string geometry and flux compactifications, applications to cosmology and particle physics, black holes in string theory and M-theory, and the microscopic origin of black-hole entropy. It concludes with Matrix theory, the AdS/CFT duality and its generalizations. This book is ideal for graduate students and researchers in modern string theory, and will make an excellent textbook for a one-year course on string theory. It contains over 120 exercises with solutions, and over 200 homework problems with solutions available on a password protected website for lecturers at www.cambridge.org/9780521860697. Comprehensive coverage of topics from basics of string theory to recent developments Ideal textbook for a one-year course in string theory Includes over 100 exercises with solutions Contains over 200 homework problems with solutions available to lecturers on-line

  2. String theory as a Lilliputian world

    International Nuclear Information System (INIS)

    Ambjørn, J.; Makeenko, Y.

    2016-01-01

    Lattice regularizations of the bosonic string do not allow us to probe the tachyon. This has often been viewed as the reason why these theories have never managed to make any contact to standard continuum string theories when the dimension of spacetime is larger than two. We study the continuum string theory in large spacetime dimensions where simple mean field theory is reliable. By keeping carefully the cutoff we show that precisely the existence of a tachyon makes it possible to take a scaling limit which reproduces the lattice-string results. We compare this scaling limit with another scaling limit which reproduces standard continuum-string results. If the people working with lattice regularizations of string theories are akin to Gulliver they will view the standard string-world as a Lilliputian world no larger than a few lattice spacings.

  3. String theory as a Lilliputian world

    Energy Technology Data Exchange (ETDEWEB)

    Ambjørn, J., E-mail: ambjorn@nbi.dk [The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); IMAPP, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands); Makeenko, Y., E-mail: makeenko@nbi.dk [The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow (Russian Federation)

    2016-05-10

    Lattice regularizations of the bosonic string do not allow us to probe the tachyon. This has often been viewed as the reason why these theories have never managed to make any contact to standard continuum string theories when the dimension of spacetime is larger than two. We study the continuum string theory in large spacetime dimensions where simple mean field theory is reliable. By keeping carefully the cutoff we show that precisely the existence of a tachyon makes it possible to take a scaling limit which reproduces the lattice-string results. We compare this scaling limit with another scaling limit which reproduces standard continuum-string results. If the people working with lattice regularizations of string theories are akin to Gulliver they will view the standard string-world as a Lilliputian world no larger than a few lattice spacings.

  4. Dynamical AdS strings across horizons

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Takaaki [University of Colorado,390 UCB, Boulder, CO 80309 (United States); Murata, Keiju [Keio University,4-1-1 Hiyoshi, Yokohama 223-8521 (Japan)

    2016-03-07

    We examine the nonlinear classical dynamics of a fundamental string in anti-de Sitter spacetime. The string is dual to the flux tube between an external quark-antiquark pair in N=4 super Yang-Mills theory. We perturb the string by shaking the endpoints and compute its time evolution numerically. We find that with sufficiently strong perturbations the string continues extending and plunges into the Poincaré horizon. In the evolution, effective horizons are also dynamically created on the string worldsheet. The quark and antiquark are thus causally disconnected, and the string transitions to two straight strings. The forces acting on the endpoints vanish with a power law whose slope depends on the perturbations. The condition for this transition to occur is that energy injection exceeds the static energy between the quark-antiquark pair.

  5. Magnet pole tips

    Science.gov (United States)

    Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

    1984-04-24

    An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

  6. MicroRNAs as new maestro conducting the expanding symphony orchestra of regenerative and reparative medicine.

    Science.gov (United States)

    Sen, Chandan K

    2011-05-01

    The human genome encodes 1,048 microRNAs (miRNAs). These miRNAs regulate virtually all biological processes. Leaving ignominy on the significance miRNAs behind we are approaching a new era in tissue repair where an ever expanding orchestra of events that enable tissue repair and regeneration seems to be conducted by miRNAs as the maestro. microRNAs are emerging as molecular rheostats that fine-tune and switch regulatory circuits governing tissue repair. Key elements of tissue repair such as stem cell biology, inflammation, hypoxia-response, and angiogenesis are all under the sophisticated control of a network of specific mRNAs. Embryonic stem cells lacking miRNAs lose their "stemness." Manipulation of specific cellular miRNAs helps enhance reprogramming of somatic cells to an embryonic stem cell-like phenotype helping generate inducible pluripotent stem cells. Expression of miRNAs is subject to control by epigenetic factors. Such control influences the balance between proliferation and differentiation of stem cells. Angiomirs regulate various aspects of angiogenesis, such as proliferation, migration, and morphogenesis of endothelial cells. MiRNAs play a key role in resolution of inflammation. Hypoxia-inducible mRNAs or hypoxamirs suppress mitochondrial respiration, cause cell cycle arrest, and interfere with growth factor signaling. miRNA-210 is a good example in this category that impairs wound closure. As fine tools enabling specific and temporally controlled manipulation of cell-specific miRNAs emerge, miRNA-based therapies hold promise in facilitating tissue repair. Treatment of skin wounds has lower barriers because it lends itself to local delivery of miRNA mimics and antagonizing agents minimizing risks associated with systemic off-target toxicity.

  7. Tips from the Classroom.

    Science.gov (United States)

    Wilhelm, Kim Hughes; Leverett, Thomas; Barrett, Rob J.; Chur-Hansen, Anna; Dantas-Whitney, Maria; Zapata, Gabriela; Garcia, Juan Felix

    1998-01-01

    Five articles present tips for rallying English-as-a-Second-Language students to the enterprise of creating context, tools, and language itself. The articles focus on using original dramas created by students, teaching nonnative English-speaking medical students to comprehend their patients' colloquial language, conducting research with native…

  8. Air Travel Health Tips

    Science.gov (United States)

    ... Conditions Prevention and Wellness Staying Healthy Healthy Living Travel Occupational Health First Aid and Injury Prevention Crisis ... MoreDepression in Children and TeensRead MoreBMI Calculator International Travel: Tips for Staying HealthyTexting and DrivingTravel Needs for ...

  9. 10 Data Visualization Tips

    International Development Research Centre (IDRC) Digital Library (Canada)

    Office 2004 Test Drive User

    communicated through the use of design choices. (as indicated in tip 8). 8. Use colour, size, and position to help the reader see what is important. Colour adds emphasis, highlights particular data points, and draws connections between graphs. The hue, value, and intensity of the colour are significant and may have cultural ...

  10. Sports Dehydration Safety Tips

    Science.gov (United States)

    Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

  11. Remarks on entanglement entropy in string theory

    Science.gov (United States)

    Balasubramanian, Vijay; Parrikar, Onkar

    2018-03-01

    Entanglement entropy for spatial subregions is difficult to define in string theory because of the extended nature of strings. Here we propose a definition for bosonic open strings using the framework of string field theory. The key difference (compared to ordinary quantum field theory) is that the subregion is chosen inside a Cauchy surface in the "space of open string configurations." We first present a simple calculation of this entanglement entropy in free light-cone string field theory, ignoring subtleties related to the factorization of the Hilbert space. We reproduce the answer expected from an effective field theory point of view, namely a sum over the one-loop entanglement entropies corresponding to all the particle-excitations of the string, and further show that the full string theory regulates ultraviolet divergences in the entanglement entropy. We then revisit the question of factorization of the Hilbert space by analyzing the covariant phase-space associated with a subregion in Witten's covariant string field theory. We show that the pure gauge (i.e., BRST exact) modes in the string field become dynamical at the entanglement cut. Thus, a proper definition of the entropy must involve an extended Hilbert space, with new stringy edge modes localized at the entanglement cut.

  12. Matrix strings in weakly curved background fields

    International Nuclear Information System (INIS)

    Schiappa, Ricardo

    2001-01-01

    We investigate further the recent proposal for the form of the Matrix theory action in weak background fields. We perform DVV reduction to the multiple D0-brane action in order to find the Matrix string theory action for multiple fundamental strings in curved but weak NSNS and RR backgrounds. This matrix sigma model gives a definite prescription on how to deal with RR fields with an explicit spacetime dependence in Type II string theory. We do this both via the 9-11 flip and the chain of T and S dualities, and further check on their equivalence explicitly. In order to do so, we also discuss the implementation of S-duality in the operators of the 2-dimensional worldvolume supersymmetric gauge theory describing the Type IIB D-string. We compare the result to the known Green-Schwarz sigma model action (for one string), and use this comparison in order to discuss about possible, non-linear background curvature corrections to the Matrix string action (involving many strings), and therefore to the Matrix theory action. We illustrate the nonabelian character of our action with an example involving multiple fundamental strings in a nontrivial RR flux, where the strings are polarized into a noncommutative configuration. This corresponds to a dielectric type of effect on fundamental strings

  13. Persistent homology and string vacua

    Energy Technology Data Exchange (ETDEWEB)

    Cirafici, Michele [Center for Mathematical Analysis, Geometry and Dynamical Systems,Instituto Superior Técnico, Universidade de Lisboa,Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Institut des Hautes Études Scientifiques,Le Bois-Marie, 35 route de Chartres, F-91440 Bures-sur-Yvette (France)

    2016-03-08

    We use methods from topological data analysis to study the topological features of certain distributions of string vacua. Topological data analysis is a multi-scale approach used to analyze the topological features of a dataset by identifying which homological characteristics persist over a long range of scales. We apply these techniques in several contexts. We analyze N=2 vacua by focusing on certain distributions of Calabi-Yau varieties and Landau-Ginzburg models. We then turn to flux compactifications and discuss how we can use topological data analysis to extract physical information. Finally we apply these techniques to certain phenomenologically realistic heterotic models. We discuss the possibility of characterizing string vacua using the topological properties of their distributions.

  14. On noncommutative open string theories

    International Nuclear Information System (INIS)

    Russo, J.G.; Sheikh-Jabbari, M.M.

    2000-08-01

    We investigate new compactifications of OM theory giving rise to a 3+1 dimensional open string theory with noncommutative x 0 -x 1 and x 2 -x 3 coordinates. The theory can be directly obtained by starting with a D3 brane with parallel (near critical) electric and magnetic field components, in the presence of a RR scalar field. The magnetic parameter permits to interpolate continuously between the x 0 -x 1 noncommutative open string theory and the x 2 -x 3 spatial noncommutative U(N) super Yang-Mills theory. We discuss SL(2, Z) transformations of this theory. Using the supergravity description of the large N limit, we also compute corrections to the quark-antiquark Coulomb potential arising in the NCOS theory. (author)

  15. Electric drill-string telemetry

    CERN Document Server

    Carcione, J M

    2003-01-01

    We design a numerical algorithm for simulation of low-frequency electric-signal transmission through a drill string. This is represented by a transmission line with varying geometrical and electromagnetic properties versus depth, depending on the characteristics of the drill-string/formation system. These properties are implicitly modeled by the series impedance and the shunt admittance of the transmission line. The differential equations are parabolic, since at low frequencies the wave field is diffusive. We use an explicit scheme for the solution of parabolic problems, based on a Chebyshev expansion of the evolution operator and the Fourier pseudospectral method to compute the spatial derivatives. The results are verified by comparison to analytical solutions obtained for the initial-value problem with a voltage source.

  16. Wrapping rules (in) string theory

    Science.gov (United States)

    Bergshoeff, Eric A.; Riccioni, Fabio

    2018-01-01

    In this paper we show that the number of all 1/2-BPS branes in string theory compactified on a torus can be derived by universal wrapping rules whose formulation we present. These rules even apply to branes in less than ten dimensions whose ten-dimensional origin is an exotic brane. In that case the wrapping rules contain an additional combinatorial factor that is related to the highest dimension in which the ten-dimensional exotic brane, after compactification, can be realized as a standard brane. We show that the wrapping rules also apply to cases with less supersymmetry. As a specific example, we discuss the compactification of IIA/IIB string theory on ( T 4/ ℤ 2) × T n .

  17. Precise Analysis of String Expressions

    DEFF Research Database (Denmark)

    Christensen, Aske Simon; Møller, Anders; Schwartzbach, Michael Ignatieff

    2003-01-01

    , including statically checking the syntax of dynamically generated expressions, such as SQL queries. Our analysis constructs flow graphs from class files and generates a context-free grammar with a nonterminal for each string expression. The language of this grammar is then widened into a regular language......We perform static analysis of Java programs to answer a simple question: which values may occur as results of string expressions? The answers are summarized for each expression by a regular language that is guaranteed to contain all possible values. We present several applications of this analysis...... are automatically produced. We present extensive benchmarks demonstrating that the analysis is efficient and produces results of useful precision....

  18. Chronology protection in string theory

    International Nuclear Information System (INIS)

    Dyson, Lisa

    2004-01-01

    Many solutions of General Relativity appear to allow the possibility of time travel. This was initially a fascinating discovery, but geometries of this type violate causality, a basic physical law which is believed to be fundamental. Although string theory is a proposed fundamental theory of quantum gravity, geometries with closed timelike curves have resurfaced as solutions to its low energy equations of motion. In this paper, we will study the class of solutions to low energy effective supergravity theories related to the BMPV black hole and the rotating wave-D1-D5-brane system. Time travel appears to be possible in these geometries. We will attempt to build the causality violating regions and propose that stringy effects prohibit their construction. The proposed chronology protection agent for these geometries mirrors a mechanism string theory employs to resolve a class of naked singularities. (author)

  19. LHC magnet string in 1994

    CERN Multimedia

    1994-01-01

    On 6-7 December 1994, a string of powerful superconducting magnets for CERN's next particle accelerator, the Large Hadron Collider (LHC), ran successfully at 8.36 tesla for 24 hours. This magnetic field is 100 000 times that of the Earth and is required to keep beams of protons travelling on the correct circular path over 27 km at 7 TeV in the new LHC accelerator.

  20. Algebras, lattices and strings 1986

    International Nuclear Information System (INIS)

    Olive, D.

    1987-01-01

    The formulation of the string theory of unified elementary particle interactions in terms of operators in a Fock space is now seen to relate to the representation theory of certain infinite dimensional algebras. This insight has enhanced the understanding of the physical and mathematical theories involved and furthermore has led to applications in other branches of theoretical physics. A brief account of the new results is given here. (orig.)

  1. Acoustical properties of drill strings

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, D.S.

    1988-08-01

    The recovery of petrochemical and geothermal resources requires extensive drilling of wells to increasingly greater depths. Real-time collection and telemetry of data about the drilling process while it occurs thousands of feet below the surface is an effective way of improving the efficiency of drilling operations. Unfortunately, due to hostile down-hole environments, telemetry of this data is an extremely difficult problem. Currently, commercial systems transmit data to the surface by producing pressure pulses within the portion of the drilling mud enclosed in the hollow steel drill string. Transmission rates are between two and four data bits per second. Any system capable of raising data rates without increasing the complexity of the drilling process will have significant economic impact. One alternative system is based upon acoustical carrier waves generated within the drill string itself. If developed, this method would accommodate data rates up to 100 bits per second. Unfortunately, the drill string is a periodic structure of pipe and threaded tool joints, the transmission characteristics are very complex and exhibit a banded and dispersive structure. Over the past forty years, attempts to field systems based upon this transmission method have resulted in little success. This paper examines this acoustical transmission problem in great detail. The basic principles of acoustic wave propagation in the periodic structure of the drill string are examined through theory, laboratory experiment, and field test. The results indicate the existence of frequency bands which are virtually free of attenuation and suitable for data transmission at high bit rates. 9 refs., 38 figs., 2 tabs.

  2. Bosonization methods in string theory

    International Nuclear Information System (INIS)

    Abdalla, E.

    1988-02-01

    The use of bosonization/fermionization techniques to convert non-linear operators of the dual, is discussed. Non abelian bosonization to the case where the central charge of the Kac-Moody algebra is not unity, is generalized. In particular, using this generalization of non-abelian bosonization, the bosonic string vertex of the compactified theory; turns out to be fundamental field of thre fermionic theory, or bound states of it thus permiting explicit computations easily. (author) [pt

  3. Apparatus and method for vibrating a casing string during cementing

    International Nuclear Information System (INIS)

    Rankin, R.E.; Rankin, K.T.

    1992-01-01

    This patent describes a method of cementing a string of casing in a well. It comprises: securing a vibrating device into the string of casing near the lower end of the string of casing; lowering the string of casing into the well to the desired depth; pumping a cement slurry down the string of casing; causing a portion of the cement slurry being pumped down the string of casing to vibrate the vibrating device; and wherein the vibrating device is secured in the string of casing by cementing the vibrating device within a sub, then securing the sub into the string of casing prior to lowering the string of casing into the well

  4. Cosmological Consequences of String Axions

    Energy Technology Data Exchange (ETDEWEB)

    Kain, Ben

    2005-12-15

    Axion fluctuations generated during inflation lead to isocurvature and non-Gaussian temperature fluctuations in the cosmic microwave background radiation. Following a previous analysis for the model independent string axion we consider the consequences of a measurement of these fluctuations for two additional string axions. We do so independent of any cosmological assumptions except for the axions being massless during inflation. The first axion has been shown to solve the strong CP problem for most compactifications of the heterotic string while the second axion, which does not solve the strong CP problem, obeys a mass formula which is independent of the axion scale. We find that if gravitational waves interpreted as arising from inflation are observed by the PLANCK polarimetry experiment with a Hubble constant during inflation of H{sub inf} {approx}> 10{sup 13} GeV the existence of the first axion is ruled out and the second axion cannot obey the scale independent mass formula. In an appendix we quantitatively justify the often held assumption that temperature corrections to the zero temperature QCD axion mass may be ignored for temperatures T {approx}< {Lambda}{sub QCD}.

  5. A different kind of string

    International Nuclear Information System (INIS)

    Caselle, Michele; Panero, Marco; Pellegrini, Roberto; Vadacchino, Davide

    2015-01-01

    In U(1) lattice gauge theory in three spacetime dimensions, the problem of confinement can be studied analytically in a semi-classical approach, in terms of a gas of monopoles with Coulomb-like interactions. In addition, this theory can be mapped to a spin model via an exact duality transformation, which allows one to perform high-precision numerical studies of the confining potential. Taking advantage of these properties, we carried out an accurate investigation of the effective string describing the low-energy properties of flux tubes in this confining gauge theory. We found striking deviations from the expected Nambu-Goto-like behavior, and, for the first time, evidence for contributions that can be described by a term proportional to the extrinsic curvature of the effective string worldsheet. Such term is allowed by Lorentz invariance, and its presence in the infrared regime of the U(1) model was indeed predicted by Polyakov several years ago. Our results show that this term scales as expected according to Polyakov’s solution, and becomes the dominant contribution to the effective string action in the continuum limit. We also demonstrate analytically that the corrections to the confining potential induced by the extrinsic curvature term can be related to the partition function of the massive perturbation of a c=1 bosonic conformal field theory. The implications of our results for SU(N) Yang-Mills theories in three and in four spacetime dimensions are discussed.

  6. Braiding knots with topological strings

    International Nuclear Information System (INIS)

    Gu, Jie

    2015-08-01

    For an arbitrary knot in a three-sphere, the Ooguri-Vafa conjecture associates to it a unique stack of branes in type A topological string on the resolved conifold, and relates the colored HOMFLY invariants of the knot to the free energies on the branes. For torus knots, we use a modified version of the topological recursion developed by Eynard and Orantin to compute the free energies on the branes from the Aganagic-Vafa spectral curves of the branes, and find they are consistent with the known colored HOMFLY knot invariants a la the Ooguri-Vafa conjecture. In addition our modified topological recursion can reproduce the correct closed string free energies, which encode the information of the background geometry. We conjecture the modified topological recursion is applicable for branes associated to hyperbolic knots as well, encouraged by the observation that the modified topological recursion yields the correct planar closed string free energy from the Aganagic-Vafa spectral curves of hyperbolic knots. This has implications for the knot theory concerning distinguishing mutant knots with colored HOMFLY invariants. Furthermore, for hyperbolic knots, we present methods to compute colored HOMFLY invariants in nonsymmetric representations of U(N). The key step in this computation is computing quantum 6j-symbols in the quantum group U q (sl N ).

  7. A different kind of string

    Science.gov (United States)

    Caselle, Michele; Panero, Marco; Pellegrini, Roberto; Vadacchino, Davide

    2015-01-01

    In U(1) lattice gauge theory in three spacetime dimensions, the problem of confinement can be studied analytically in a semi-classical approach, in terms of a gas of monopoles with Coulomb-like interactions. In addition, this theory can be mapped to a spin model via an exact duality transformation, which allows one to perform high-precision numerical studies of the confining potential. Taking advantage of these properties, we carried out an accurate investigation of the effective string describing the low-energy properties of flux tubes in this confining gauge theory. We found striking deviations from the expected Nambu-Goto-like behavior, and, for the first time, evidence for contributions that can be described by a term proportional to the extrinsic curvature of the effective string worldsheet. Such term is allowed by Lorentz invariance, and its presence in the infrared regime of the U(1) model was indeed predicted by Polyakov several years ago. Our results show that this term scales as expected according to Polyakov's solution, and becomes the dominant contribution to the effective string action in the continuum limit. We also demonstrate analytically that the corrections to the confining potential induced by the extrinsic curvature term can be related to the partition function of the massive perturbation of a c = 1 bosonic conformal field theory. The implications of our results for SU( N ) Yang-Mills theories in three and in four spacetime dimensions are discussed.

  8. A different kind of string

    Energy Technology Data Exchange (ETDEWEB)

    Caselle, Michele [Dipartimento di Fisica dell’Università di Torino and INFN - Sezione di Torino,Via P. Giuria 1, I-10125 Torino (Italy); Panero, Marco [Dipartimento di Fisica dell’Università di Torino and INFN - Sezione di Torino,Via P. Giuria 1, I-10125 Torino (Italy); Instituto de Física Téorica UAM/CSIC, Universidad Autónoma de Madrid,Calle Nicolás Cabrera 13-15, Cantoblanco E-28049 Madrid (Spain); Pellegrini, Roberto [Physics Department, Swansea University,Singleton Park, Swansea SA2 8PP (United Kingdom); Vadacchino, Davide [Dipartimento di Fisica dell’Università di Torino and INFN - Sezione di Torino,Via P. Giuria 1, I-10125 Torino (Italy)

    2015-01-20

    In U(1) lattice gauge theory in three spacetime dimensions, the problem of confinement can be studied analytically in a semi-classical approach, in terms of a gas of monopoles with Coulomb-like interactions. In addition, this theory can be mapped to a spin model via an exact duality transformation, which allows one to perform high-precision numerical studies of the confining potential. Taking advantage of these properties, we carried out an accurate investigation of the effective string describing the low-energy properties of flux tubes in this confining gauge theory. We found striking deviations from the expected Nambu-Goto-like behavior, and, for the first time, evidence for contributions that can be described by a term proportional to the extrinsic curvature of the effective string worldsheet. Such term is allowed by Lorentz invariance, and its presence in the infrared regime of the U(1) model was indeed predicted by Polyakov several years ago. Our results show that this term scales as expected according to Polyakov’s solution, and becomes the dominant contribution to the effective string action in the continuum limit. We also demonstrate analytically that the corrections to the confining potential induced by the extrinsic curvature term can be related to the partition function of the massive perturbation of a c=1 bosonic conformal field theory. The implications of our results for SU(N) Yang-Mills theories in three and in four spacetime dimensions are discussed.

  9. Resumming the string perturbation series

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, Alba; Mariño, Marcos; Zakany, Szabolcs [Département de Physique Théorique et section de Mathématiques,Université de Genève, Genève, CH-1211 (Switzerland)

    2015-05-07

    We use the AdS/CFT correspondence to study the resummation of a perturbative genus expansion appearing in the type II superstring dual of ABJM theory. Although the series is Borel summable, its Borel resummation does not agree with the exact non-perturbative answer due to the presence of complex instantons. The same type of behavior appears in the WKB quantization of the quartic oscillator in Quantum Mechanics, which we analyze in detail as a toy model for the string perturbation series. We conclude that, in these examples, Borel summability is not enough for extracting non-perturbative information, due to non-perturbative effects associated to complex instantons. We also analyze the resummation of the genus expansion for topological string theory on local ℙ{sup 1}×ℙ{sup 1}, which is closely related to ABJM theory. In this case, the non-perturbative answer involves membrane instantons computed by the refined topological string, which are crucial to produce a well-defined result. We give evidence that the Borel resummation of the perturbative series requires such a non-perturbative sector.

  10. Informing New String Programmes: Lessons Learned from an Australian Experience

    Science.gov (United States)

    Murphy, Fintan; Rickard, Nikki; Gill, Anneliese; Grimmett, Helen

    2011-01-01

    Although there are many examples of notable string programmes there has been relatively little comparative analysis of these programmes. This paper examines three benchmark string programmes (The University of Illinois String Project, The Tower Hamlets String Teaching Project and Colourstrings) alongside Music4All, an innovative string programme…

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... TIPS. top of page What are some common uses of the procedure? A TIPS is used to ... the scanner by a cord. Some exams may use different transducers (with different capabilities) during a single ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... or bypass, without the risks that accompany open surgery. TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS should have less of an effect ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... then placed in this tunnel to keep the pathway open. Patients who typically need a TIPS have ... and stomach. A TIPS procedure involves creating a pathway through the liver that connects the portal vein ( ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... and/or hydrothorax (in the chest). Budd-Chiari syndrome , a blockage in one or more veins that ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... heart while avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in ... TIPS reroutes blood flow in the liver and reduces abnormally high blood pressure in the veins of ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... taking our brief survey: Survey Do you have a personal story about radiology? Share your patient story ...

  17. Ergonomic activity analysis of the musicians of the Symphony Orchestra of Paraná state: risk factors and workloads

    Directory of Open Access Journals (Sweden)

    Jaqueline de Lima

    2014-04-01

    Full Text Available This study aimed to investigate the risk factors present in the work activity and their impact on the health of the musicians of the Symphony Orchestra of Parana state. It is a descriptive qualitative research based on the method of Ergonomic Workplace Analysis of Francophone strand, used as a tool by occupational therapists in the health-work interface. The following procedures were performed: bibliographical survey, documental analysis of productivity data, production and quality of the task, systematic observation of the rehearsals of the Symphony Orchestra of Parana, task and workplace analysis with the application of Ergonomic Workplace Analysis (EWA and, confrontation of the data analyzed with an instrumental musician. As a result, the study showed significant deviations with reference to the standards described in Brazilian Norm 17 (Ergonomics, especially regarding individual cognitive and physical demands as well as demands related to work organization, considering each item evaluated by this analytical instrument. The action of occupational therapy was grounded on the insertion in the health and illness process, health promotion, illness prevention, and training of musicians as workers and social actors, envisioning the transformation of work situations.

  18. A novel string field theory solving string theory by liberating left and right movers

    International Nuclear Information System (INIS)

    Nielsen, Holger B.; Ninomiya, Masao

    2014-01-01

    We put forward ideas to a novel string field theory based on making some “objects” that essentially describe “liberated” left- and right- mover fields X L μ (τ+σ) and X R μ (τ−σ) on the string. Our novel string field theory is completely definitely different from any other string theory in as far as a “null set” of information in the string field theory Fock space has been removed relatively, to the usual string field theories. So our theory is definitely new. The main progress is that we manage to make our novel string field theory provide the correct mass square spectrum for the string. We finally suggest how to obtain the Veneziano amplitude in our model

  19. Micro string resonators as temperature sensors

    DEFF Research Database (Denmark)

    Larsen, T.; Schmid, S.; Boisen, A.

    2013-01-01

    The resonance frequency of strings is highly sensitive to temperature. In this work we have investigated the applicability of micro string resonators as temperature sensors. The resonance frequency of strings is a function of the tensile stress which is coupled to temperature by the thermal...... to the low thermal mass of the strings. A temperature resolution of 2.5×10-4 °C has been achieved with silicon nitride strings. The theoretical limit for the temperature resolution of 8×10-8 °C has not been reached yet and requires further improvement of the sensor....... expansion of the string and the frame clamping it. The sensitivity improves when the length and pre-stress are reduced and the difference in thermal expansion, Young's modulus and resonant mode are increased. At low tensile stress, the sensitivity becomes highly dependent on temperature. The investigation...

  20. String theory and quantum gravity '92

    International Nuclear Information System (INIS)

    Harvey, J.; Iengo, R.; Narain, K.S.; Randjbar Daemi, S.; Verlinde, H.

    1993-01-01

    These proceedings of the 1992 Trieste Spring School and Workshop on String Theory and Quantum Gravity contains introductions and overviews of recent work on the use of two-dimensional string inspired models in the study of black holes, a lecture on gravitational scattering at planckian energies, another on the physical properties of higher-dimensional black holes and black strings in string theory, a discussion on N=2 superconformal field theories, a lecture about the application of matrix model techniques to the study of string theory in two dimensions, and an overview of the current status and developments in string field theory. Connections with models in statistical mechanics are also discussed. These proceedings contain seven lectures and ten contributions. Refs and figs

  1. D-branes from Liouville strings

    CERN Document Server

    Ellis, Jonathan Richard; Nanopoulos, Dimitri V

    1997-01-01

    We develop quantization aspects of our Liouville approach to non-critical strings, proposing a path-integral formulation of a second quantization of string theory, that incorporates naturally the couplings of string sources to background fields. Such couplings are characteristic of macroscopic string solutions and/or D-brane theories. Resummation over world-sheet genera in the presence of stringy (\\sigma-model) soliton backgrounds, and recoil effects associated with logarithmic operators on the world sheet, play a crucial r\\^ole in inducing such sources as well-defined renormalization-group counterterms. Using our Liouville renormalization group approach, we derive the appropriate second-order equation of motion for the D brane. We discuss within this approach the appearance of open strings, whose ends carry non-trivial Chan-Paton-like quantum numbers related to the W_\\infty charges of two-dimensional string black holes.

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... liver disease are at greater risk for worsening liver failure after TIPS. If your liver failure is severe, a TIPS may not be the best use and a different procedure may be needed to control your symptoms. ... ordinarily filtered out by the liver. The TIPS may cause too much of these ...

  3. String and M-theory cosmology

    International Nuclear Information System (INIS)

    Copeland, E.J.

    2003-01-01

    In these lectures we review recent advances in string cosmology. Starting with the Dilaton-Moduli Cosmology (known also as the Pre Big Bang), we go on to include the effects of axion fields and address the thorny issue of the Graceful Exit in String Cosmology. This is followed by a review of density perturbations arising in string cosmology and we finish with a brief introduction to the impact moving of five branes on the Dilaton-Moduli cosmological solutions

  4. String model of black hole microstates

    International Nuclear Information System (INIS)

    Larsen, F.

    1997-01-01

    The statistical mechanics of black holes arbitrarily far from extremality is modeled by a gas of weakly interacting strings. As an effective low-energy description of black holes the string model provides several highly nontrivial consistency checks and predictions. Speculations on a fundamental origin of the model suggest surprising simplifications in nonperturbative string theory, even in the absence of supersymmetry. copyright 1997 The American Physical Society

  5. Exact solutions and singularities in string theory

    International Nuclear Information System (INIS)

    Horowitz, G.T.; Tseytlin, A.A.

    1994-01-01

    We construct two new classes of exact solutions to string theory which are not of the standard plane wave of gauged WZW type. Many of these solutions have curvature singularities. The first class includes the fundamental string solution, for which the string coupling vanishes near the singularity. This suggests that the singularity may not be removed by quantum corrections. The second class consists of hybrids of plane wave and gauged WZW solutions. We discuss a four-dimensional example in detail

  6. Time dependent viscous string cloud cosmological models

    Science.gov (United States)

    Tripathy, S. K.; Nayak, S. K.; Sahu, S. K.; Routray, T. R.

    2009-09-01

    Bianchi type-I string cosmological models are studied in Saez-Ballester theory of gravitation when the source for the energy momentum tensor is a viscous string cloud coupled to gravitational field. The bulk viscosity is assumed to vary with time and is related to the scalar expansion. The relationship between the proper energy density ρ and string tension density λ are investigated from two different cosmological models.

  7. Quantum corrections to the string Bethe ansatz

    CERN Document Server

    Hernández, R; Hernandez, Rafael; Lopez, Esperanza

    2006-01-01

    One-loop corrections to the energy of semiclassical rotating strings contain both analytic and non-analytic terms in the 't Hooft coupling. Analytic contributions agree with the prediction from the string Bethe ansatz based on the classical S-matrix, but in order to include non-analytic contributions quantum corrections are required. We find a general expression for the first quantum correction to the string Bethe ansatz.

  8. Parameterized String Matching Algorithms with Application to ...

    African Journals Online (AJOL)

    In the parameterized string matching problem, a given pattern P is said to match with a sub-string t of the text T, if there exist a bijection from the symbols of P to the symbols of t. Salmela and Tarhio solve the parameterized string matching problem in sub-linear time by applying the concept of q-gram in the Horspool algorithm ...

  9. p-adic string theories provide lattice Discretization to the ordinary string worldsheet.

    Science.gov (United States)

    Ghoshal, Debashis

    2006-10-13

    A class of models called p-adic strings is useful in understanding the tachyonic instability of string theory. These are found to be empirically related to the ordinary strings in the p-->1 limit. We propose that these models provide discretization for the string worldsheet and argue that the limit is naturally thought of as a continuum limit in the sense of the renormalization group.

  10. Matrix string models for exact (2,2) string theories in RR backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Bonelli, Giulio E-mail: gbonelli@ulb.ac.be

    2003-01-20

    We formulate matrix string models on a class of exact string backgrounds with non-constant RR-flux parameterized by a holomorphic prepotential function and with manifest (2,2) supersymmetry. This lifts these string theories to M-theory exposing the non-perturbative string interaction which is studied by generalizing the instanton asymptotic expansion, well established in the flat background case, to this more general case. We obtain also a companion matrix model with four manifest supersymmetries in eleven dimensions.

  11. Perturbative string theory in BRST invariant formalism

    International Nuclear Information System (INIS)

    Di Vecchia, P.; Hornfeck, K.; Frau, M.; Lerda, A.

    1988-01-01

    In this talk we present a constructive and very explicit way of calculating multiloop amplitudes in string theories. The main ingredients are the BRST invariant N String Vertex and the BRST invariant twisted propagator. This approach naturally leads to the Schottky parametrization of moduli space in terms of multipliers and fixed points of the g projective transformations which characterize a Riemann surface of genus g. The complete expression (including measure) of the multiloop corrections to the N String Vertex for the bosonic string is exhibited. (orig.)

  12. Sigma models and renormalization of string loops

    International Nuclear Information System (INIS)

    Tseytlin, A.A.

    1989-05-01

    An extension of the ''σ-model β-functions - string equations of motion'' correspondence to the string loop level is discussed. Special emphasis is made on how the renormalization group acts in string loops and, in particular, on the renormalizability property of the generating functional Z-circumflex for string amplitudes (related to the σ model partition function integrated over moduli). Renormalization of Z-circumflex at one and two loop order is analyzed in some detail. We also discuss an approach to renormalization based on operators of insertion of topological fixtures. (author). 70 refs

  13. Gauge invariant actions for string models

    International Nuclear Information System (INIS)

    Banks, T.

    1986-06-01

    String models of unified interactions are elegant sets of Feynman rules for the scattering of gravitons, gauge bosons, and a host of massive excitations. The purpose of these lectures is to describe the progress towards a nonperturbative formulation of the theory. Such a formulation should make the geometrical meaning of string theory manifest and explain the many ''miracles'' exhibited by the string Feynman rules. There are some new results on gauge invariant observables, on the cosmological constant, and on the symmetries of interacting string field theory. 49 refs

  14. Pencocokan String Berdasarkan Kemiripan Ucapan (Phonetic String Matching) dalam Bahasa Inggris

    OpenAIRE

    Syaroni, Mokhamad; Munir, Rinaldi

    2009-01-01

    Perkembangan teknologi informasi dan komunikasi yang semakin pesat, mengakibatkan pencarianinformasi semakin mudah. Pencarian informasi yang tepat dan sesuai kebutuhan menjadi sangat penting. Olehkarena itu, teknik untuk memperoleh dokumen dengan isi yang sesuai dengan kebutuhan informasi sangatdiperlukan. Untuk mengetahui isi dokumen sesuai dengan kebutuhan informasi, diperlukan metode pencarianstring (string searching) isi dokumen yang bagus. Proses pencocokan string (string matching) yang ...

  15. Pencocokan String Berdasarkan Kemiripan Ucapan (Phonetic String Matching) Dalam Bahasa Inggris

    OpenAIRE

    Syaroni, Mokhamad; Munir, Rinaldi

    2005-01-01

    Perkembangan teknologi informasi dan komunikasi yang semakin pesat, mengakibatkan pencarianinformasi semakin mudah. Pencarian informasi yang tepat dan sesuai kebutuhan menjadi sangat penting. Olehkarena itu, teknik untuk memperoleh dokumen dengan isi yang sesuai dengan kebutuhan informasi sangatdiperlukan. Untuk mengetahui isi dokumen sesuai dengan kebutuhan informasi, diperlukan metode pencarianstring (string searching) isi dokumen yang bagus. Proses pencocokan string (string matching) yang ...

  16. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... propeller, have efficiency increases of a reasonable magnitude in both open-water and behind-ship conditions....

  17. Muusikamaailm : Dresdeni festival pühendub Hispaaniale. Händeli festival Göttingenis. Siemensi preemia Arditti kvartetile. Metropolitan Opera Orchestra Euroopas. Haydni festival Inglismaal / Priit Kuusk

    Index Scriptorium Estoniae

    Kuusk, Priit, 1938-

    1999-01-01

    21.05-6.06 toimuvast Dresdeni muusikafestivalist. Händelipidustuste tippsündmuseks on helilooja harvaesitatava ooperi "Arianna in Creta" ettekanne. Ernst von Siemensi Fondi tänavuse preemia pälvis Arditti Quartet. Metropolitan Opera Orchestra Euroopa-ringreisist. 7.juunini kestvatest Haydni pidustustest Shropshire"is

  18. Recent Developments in D=2 String Field Theory

    OpenAIRE

    Kaku, Michio

    1994-01-01

    In this review article, we review the recent developments in constructing string field theories that have been proposed, all of which correctly reproduce the correlation functions of two-dimensional string theory. These include: (a) free fermion field theory (b) collective string field theory (c) temporal gauge string field theory (d) non-polynomial string field theory. We analyze discrete states, the $w(\\infty)$ symmetry, and correlation functions in terms of these different string field the...

  19. An equivalence between momentum and charge in string theory

    International Nuclear Information System (INIS)

    Horne, J.H.; Horowitz, G.T.; Steif, A.R.

    1992-01-01

    It is shown that for a translationally invariant solution to string theory, spacetime duality interchanges the momentum in the symmetry direction and the axion charge per unit length. As one application, we show explicitly that charged black strings are equivalent to boosted (uncharged) black strings. The extremal black strings (which correspond to the field outside of a fundamental macroscopic string) are equivalent to plane-fronted waves describing strings moving at the speed of light

  20. Boundary string field theory and an open string one-loop

    International Nuclear Information System (INIS)

    Lee, Tae Jin; Viswanathan, K. S.; Yang, Yi

    2003-01-01

    We discuss the open string one-loop partition function in the tachyon condensation background of an unstable D-brane system. We evaluate the partition function by using the boundary-state formulation and find that it is in complete agreement with the result obtained in the boundary string field theory. This suggests that the open string higher loop diagrams may be produced consistently by using a closed string field theory, where the D-brane plays the role of a source for the closed string field

  1. On the elliptic genus of three E-strings and heterotic strings

    International Nuclear Information System (INIS)

    Cai, Wenhe; Huang, Min-xin; Sun, Kaiwen

    2015-01-01

    A precise formula for the elliptic genus of three E-strings is presented. The related refined free energy coincides with the result calculated from topological string on local half K3 Calabi-Yau threefold up to genus twelve. The elliptic genus of three heterotic strings computed from M9 domain walls matches with the result from orbifold formula to high orders. This confirms the n=3 case of the recent conjecture that n pairs of E-strings can recombine into n heterotic strings.

  2. Open strings in the SL(2, R) WZWN model with solution for a rigidly rotating string

    DEFF Research Database (Denmark)

    Lomholt, Michael Andersen; Larsen, A.L.

    2003-01-01

    then consider open string boundary conditions corresponding to a certain field-dependent gluing condition. This allows us to consider open strings with constant energy and angular momentum. Classically, these open strings naturally generalize the open strings in flat Minkowski space. For rigidly rotating open...... strings, we show that the torsion leads to a bending and an unfolding. We also derive the SL(2, R) Regge relation, which generalizes the linear Minkowski Regge relation. For "high" mass, it takes the form L ≈ ± M/H, where H is the scale of the SL(2, R) group manifold....

  3. String Motion in Fivebrane Geometry

    OpenAIRE

    Khuri, Ramzi R.; La, HoSeong

    1992-01-01

    The classical motion of a test string in the transverse space of two types of heterotic fivebrane sources is fully analyzed, for arbitrary instanton scale size. The singular case is treated as a special case and does not arise in the continuous limit of zero instanton size. We find that the orbits are either circular or open, which is a solitonic analogy with the motion of an electron around a magnetic monopole, although the system we consider is quantitatively different. We emphasize that at...

  4. String inflation after Planck 2013

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, C.P. [Department of Physics and Astronomy, McMaster University, Hamilton ON (Canada); Cicoli, M. [Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126 Bologna (Italy); Quevedo, F., E-mail: cburgess@perimeterinstitute.ca, E-mail: mcicoli@ictp.it, E-mail: F.Quevedo@damtp.cam.ac.uk [Abdus Salam ICTP, Strada Costiera 11, Trieste 34014 (Italy)

    2013-11-01

    We briefly summarize the impact of the recent Planck measurements for string inflationary models, and outline what might be expected to be learned in the near future from the expected improvement in sensitivity to the primordial tensor-to-scalar ratio. We comment on whether these models provide sufficient added value to compensate for their complexity, and ask how they fare in the face of the new constraints on non-gaussianity and dark radiation. We argue that as a group the predictions made before Planck agree well with what has been seen, and draw conclusions from this about what is likely to mean as sensitivity to primordial gravitational waves improves.

  5. A Note on Tensionless Strings in M-Theory

    OpenAIRE

    Davis, K.

    1996-01-01

    In this article we examine the appearance of tensionless strings in M-Theory. We subsequently interpret these tensionless strings in a String Theory context. In particular, we examine tensionless strings appearing in M-Theory on $S^{1}$, M-Theory on $S^{1} / {\\bf Z}_{2}$, and M-Theory on $T^{2}$; we then interpret the appearance of such strings in a String Theory context. Then we reverse this process and examine the appearance of some tensionless strings in String Theory. Subsequently we inte...

  6. Prevalence and consequences of musculoskeletal symptoms in symphony orchestra musicians vary by gender: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Paarup Helene M

    2011-10-01

    Full Text Available Abstract Background Musculoskeletal symptoms are common in the neck, back, and upper limbs amongst musicians. Playing-related musculoskeletal disorders have been found to range from 32% to 87% with a tendency for female musicians to have more problems than males. Studies of musculoskeletal problems in instrumentalists have generally involved pre-professional musicians or populations comprising musicians of different levels. The objective of this study was therefore to investigate the prevalence, duration and consequences of musculoskeletal symptoms in professional symphony orchestra musicians. Methods A cross-sectional questionnaire study. The study population comprised of 441 musicians from six Danish symphony orchestras; 342 (78% completed the questionnaire. Results During the last year 97% of the women and 83% of the men experienced symptoms in at least one of nine anatomic regions (neck, upper and lower back, shoulders, elbows, and hands and wrists. 86% of the women and 67% of the men experienced symptoms for more than seven days, while 63% of the women and 49% of the men had symptoms for more than 30 days. Woodwind players had a lower risk for musculoskeletal symptoms and a lower risk for the consequences. Among consequences were changed way of playing, reported by 73% of the musicians, difficulty in daily activities at home, reported by 55%, and difficulty in sleeping, reported by 49%. Their health behaviour included taking paracetamol as the most used analgesic, while physiotherapists and general practitioners were reported as the most consulted health care professionals concerning musculoskeletal problems. Results regarding symptoms in six anatomic regions were compared to results for a sample of the general Danish workforce. Symptoms were more frequent in musicians and lasted longer than in the general workforce. This applied to both genders. Conclusions Within the last year most symphony orchestra musicians experienced musculoskeletal

  7. BPS limit of multi- D- and DF-strings in boundary string field theory

    International Nuclear Information System (INIS)

    Go, Gyungchoon; Ishida, Akira; Kim, Yoonbai

    2007-01-01

    A BPS limit is systematically derived for straight multi- D- and DF-strings from the D3D-bar3 system in the context of boundary superstring field theory. The BPS limit is obtained in the limit of thin D(F)-strings, where the Bogomolny equation supports singular static multi-D(F)-string solutions. For the BPS multi-string configurations with arbitrary separations, BPS sum rule is fulfilled under a Gaussian type tachyon potential and reproduces exactly the descent relation. For the DF-strings ((p,q)-strings), the distribution of fundamental string charge density coincides with its energy density and the Hamiltonian density takes the BPS formula of square-root form

  8. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    Phase transitions of quantum fields in the early universe produced very thin tubes of false vacuum, known as cosmic strings [1]. These are topological defects which can form when either a local or a global symmetry is spontaneously broken in a phase transition. The first one is called gauge string and the latter is called ...

  9. Hydromonochord: Visualizing String Vibration by Water Swirls

    Science.gov (United States)

    Sommer, Wilfried; Meier-Boke, Ralf; Meinzer, Nicholas

    2010-01-01

    The hydromonochord is a horizontal vibrating string that just makes contact with the surface of a water bath. The motion of the string sets up a pattern of swirls on the surface of the water, thus complementing the usual pattern of nodes and antinodes. The device is based on the traditional monochord. A water basin (Fig. 1) has two slits in the…

  10. An overview of progress in string theory

    Indian Academy of Sciences (India)

    There has been many interesting developments in string theory in last couple of years. The purpose of this article is to present a brief account of the progress made in string theory. The two invited talks by S R Das and S Mukhi in this volume contain more detailed accounts of our understanding of black hole physics and the ...

  11. Face recognition using ensemble string matching.

    Science.gov (United States)

    Chen, Weiping; Gao, Yongsheng

    2013-12-01

    In this paper, we present a syntactic string matching approach to solve the frontal face recognition problem. String matching is a powerful partial matching technique, but is not suitable for frontal face recognition due to its requirement of globally sequential representation and the complex nature of human faces, containing discontinuous and non-sequential features. Here, we build a compact syntactic Stringface representation, which is an ensemble of strings. A novel ensemble string matching approach that can perform non-sequential string matching between two Stringfaces is proposed. It is invariant to the sequential order of strings and the direction of each string. The embedded partial matching mechanism enables our method to automatically use every piece of non-occluded region, regardless of shape, in the recognition process. The encouraging results demonstrate the feasibility and effectiveness of using syntactic methods for face recognition from a single exemplar image per person, breaking the barrier that prevents string matching techniques from being used for addressing complex image recognition problems. The proposed method not only achieved significantly better performance in recognizing partially occluded faces, but also showed its ability to perform direct matching between sketch faces and photo faces.

  12. Plucked String on a Shoestring Budget

    Science.gov (United States)

    Gluck, Paul

    2009-01-01

    The physics of the plucked string has been treated in many articles and books. For our 12th-grade high school physics laboratory, we have built a cheap, simple sonometer apparatus for each pair of students on which they may investigate some interesting phenomena that arise when a string is plucked. Among these are the generation of harmonics…

  13. String field representation of the Virasoro algebra

    Czech Academy of Sciences Publication Activity Database

    Mertes, N.; Schnabl, Martin

    2016-01-01

    Roč. 2016, č. 12 (2016), 1-14, č. článku 151. ISSN 1029-8479 R&D Projects: GA ČR(CZ) GA14-31689S Institutional support: RVO:68378271 Keywords : String Held Theory * Conformal Field Models in String Theory Subject RIV: BE - Theoretical Physics Impact factor: 6.063, year: 2016

  14. EFFECTIVE ACTIONS FOR HETEROTIC STRING THEORY

    NARCIS (Netherlands)

    SUELMANN, H

    Heterotic String Theory is an attempt to construct a description of nature that is more satisfying than the Standard Model. A major problem is that it is very difficult to do explicit calculations in string theory. Therefore, it is useful to construct a 'normal' field theory that approximates HST.

  15. String Theory: Big Problem for Small Size

    Science.gov (United States)

    Sahoo, S.

    2009-01-01

    String theory is the most promising candidate theory for a unified description of all the fundamental forces that exist in nature. It provides a mathematical framework that combines quantum theory with Einstein's general theory of relativity. The typical size of a string is of the order of 10[superscript -33] cm, called the Planck length. But due…

  16. Understanding fields using strings: A review

    Indian Academy of Sciences (India)

    Understanding fields using strings: A review. SUNIL MUKHI. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India. Abstract. In addition to being a prime candidate for a fundamental unified theory of all interactions in nature, string theory provides a natural setting to understand gauge field ...

  17. A Computer String-Grammar of English.

    Science.gov (United States)

    Sager, Naomi

    This volume is the fourth in a series of detailed reports on a working computer program for the syntactic analysis of English sentences into their component strings. The report (1) records the considerations involved in various decisions among alternative grammatical formulations and presents the word-subclasses, the linguistic strings, etc., for…

  18. Quantum Geometry of Refined Topological Strings

    NARCIS (Netherlands)

    Aganagic, M.; Cheng, M.C.N.; Dijkgraaf, R.; Kreft, D.; Vafa, C.

    2012-01-01

    We consider branes in refined topological strings. We argue that their wavefunctions satisfy a Schrödinger equation depending on multiple times and prove this in the case where the topological string has a dual matrix model description. Furthermore, in the limit where one of the equivariant

  19. Calculations in perturbative string field theory

    International Nuclear Information System (INIS)

    Thorn, C.B.

    1987-01-01

    The author discusses methods for evaluating the Feynman diagrams of string field theory, with particular emphasis on Witten's version of open string field theory. It is explained in some detail how the rules states by Giddings and Martinec for relating a given diagram to a Polyakov path integral emerge from the Feynman rules

  20. An overview of progress in string theory

    Indian Academy of Sciences (India)

    invariance of the theory. The string theories of interest to us contain massless particles in their lowest mode. For example, in 10-dimensional heterotic string theory, we have graviton, antisymmetric tensor and dilaton together with the super Yang–Mills multiplets corresponding to the gauge groups SO(32) or E x E in its ...

  1. Recent Progress in String Inflationary Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Rey, Soo-Jong

    2003-05-23

    Super-inflation driven by dilaton/moduli kinetic energy is naturally realized in compactified string theory. Discussed are selected topics of recent development in string inflationary cosmology: kinematics of super-inflation, graceful exit triggered by quantum back reaction, and classical and quantum power spectra of density and metric perturbations.

  2. Querying and Mining Strings Made Easy

    KAUST Repository

    Sahli, Majed

    2017-10-13

    With the advent of large string datasets in several scientific and business applications, there is a growing need to perform ad-hoc analysis on strings. Currently, strings are stored, managed, and queried using procedural codes. This limits users to certain operations supported by existing procedural applications and requires manual query planning with limited tuning opportunities. This paper presents StarQL, a generic and declarative query language for strings. StarQL is based on a native string data model that allows StarQL to support a large variety of string operations and provide semantic-based query optimization. String analytic queries are too intricate to be solved on one machine. Therefore, we propose a scalable and efficient data structure that allows StarQL implementations to handle large sets of strings and utilize large computing infrastructures. Our evaluation shows that StarQL is able to express workloads of application-specific tools, such as BLAST and KAT in bioinformatics, and to mine Wikipedia text for interesting patterns using declarative queries. Furthermore, the StarQL query optimizer shows an order of magnitude reduction in query execution time.

  3. An overview of progress in string theory

    Indian Academy of Sciences (India)

    Abstract. There has been many interesting developments in string theory in last couple of years. The purpose of this article is to present a brief account of the progress made in string theory. The two invited talks by S R Das and S Mukhi in this volume contain more detailed accounts of our understanding of black hole physics ...

  4. Total cross section of highly excited strings

    International Nuclear Information System (INIS)

    Lizzi, F.; Senda, I.

    1990-01-01

    The unpolarized total cross section for the joining of two highly excited strings is calculated. The calculation is performed by taking the average overall states in the given excitation levels of the initial strings. We find that the total cross section grows with the energy and momentum of the initial states. (author). 8 refs, 1 fig

  5. String loop effect on the BRST charge

    International Nuclear Information System (INIS)

    Das, A.; Nishino, H.

    1987-07-01

    An effective BRST charge Q BRST which incorporates the string one-loop corrections is presented for the closed bosonic string in an arbitrary background. The effective σ-model action which leads to such a Q BRST is obtained and some consequences are discussed. (author). 14 refs, 1 fig

  6. Cosmic R-string in thermal history

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Ohashi, Keisuke [Osaka City Univ. (Japan). Dept. of Mathematics and Physics; Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research

    2013-03-15

    We study stabilization of an unstable cosmic string associated with spontaneously broken U(1){sub R} symmetry, which otherwise causes a dangerous roll-over process. We demonstrate that in a gauge mediation model, messengers can receive enough corrections from the thermal plasma of the supersymmetric standard model particles to stabilize the unstable modes of the string.

  7. Confining strings revisited - a short comment

    International Nuclear Information System (INIS)

    Botelho, Luiz C.L.

    2000-03-01

    We show that Polyakov's confining string Nucl. Phys. B486, (1997) 23, is the author's previously proposed self-avoiding extrinsic strings (Luiz C.L. Botelho), Rev. Bras. Fis. 16, 279, (1986); CALTECH-preprint 68, 1444, (1987); J. Math. Phys. 30 (9), (1989), 2160). (author)

  8. Confining strings revisited - a short comment

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, Luiz C.L. [Universidade Federal Rural do Rio de Janeiro, RJ (Brazil). Dept. de Fisica

    2000-03-01

    We show that Polyakov's confining string Nucl. Phys. B486, (1997) 23, is the author's previously proposed self-avoiding extrinsic strings (Luiz C.L. Botelho), Rev. Bras. Fis. 16, 279, (1986); CALTECH-preprint 68, 1444, (1987); J. Math. Phys. 30 (9), (1989), 2160. (author)

  9. String 2, test facility for the LHC

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    String 2 is the long chain seen to the right, representing one complete cell of bending dipoles, focusing quadrupoles and corrector magnets. On 17 June 2002 the test string reached the nominal running current of 11 860 A and magnetic field of 8.335 T for the LHC.

  10. Tipping point leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2003-04-01

    When William Bratton was appointed police commissioner of New York City in 1994, turf wars over jurisdiction and funding were rife and crime was out of control. Yet in less than two years, and without an increase in his budget, Bratton turned New York into the safest large city in the nation. And the NYPD was only the latest of five law-enforcement agencies Bratton had turned around. In each case, he succeeded in record time despite limited resources, a demotivated staff, opposition from powerful vested interests, and an organization wedded to the status quo. Bratton's turnarounds demonstrate what the authors call tipping point leadership. The theory of tipping points hinges on the insight that in any organization, fundamental changes can occur quickly when the beliefs and energies of a critical mass of people create an epidemic movement toward an idea. Bratton begins by overcoming the cognitive hurdles that block organizations from recognizing the need for change. He does this by putting managers face-to-face with operational problems. Next, he manages around limitations on funds, staff, or equipment by concentrating resources on the areas that are most in need of change and that have the biggest payoffs. He meanwhile solves the motivation problem by singling out key influencers--people with disproportionate power due to their connections or persuasive abilities. Finally, he closes off resistance from powerful opponents. Not every CEO has the personality to be a Bill Bratton, but his successes are due to much more than his personality. He relies on a remarkably consistent method that any manager looking to turn around an organization can use to overcome the forces of inertia and reach the tipping point.

  11. Strings, conformal fields and topology. An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Kaku, Michio (City Coll., New York (USA). Dept. of Physics)

    1991-01-01

    String Theory has advanced at an astonishing pace in the last few years, and this book aims to acquaint the reader with the most active topics of research in the field. Building on the foundations laid in his Introduction to Superstrings, Professor Kaku discusses such topics as the classification of conformal string theories, knot theory, the Yang-Baxter relation, quantum groups, the non-polynominal closed string field theory, matrix models, and topological field theory. Several chapters review the fundamentals of string theory, making the presentation of the material self-contained while keeping overlap with the earlier book to a minimum. The book conveys the vitality of current research in string theory and places readers at its forefront. (orig.) With 40 figs. in 50 parts.

  12. Correspondence principle for black holes and strings

    International Nuclear Information System (INIS)

    Horowitz, G.T.; Polchinski, J.

    1997-01-01

    For most black holes in string theory, the Schwarzschild radius in string units decreases as the string coupling is reduced. We formulate a correspondence principle, which states that (i) when the size of the horizon drops below the size of a string, the typical black hole state becomes a typical state of strings and D-branes with the same charges, and (ii) the mass does not change abruptly during the transition. This provides a statistical interpretation of black hole entropy. This approach does not yield the numerical coefficient, but gives the correct dependence on mass and charge in a wide range of cases, including neutral black holes. copyright 1997 The American Physical Society

  13. Compressed and Practical Data Structures for Strings

    DEFF Research Database (Denmark)

    Christiansen, Anders Roy

    in the following. Finger Search in Grammar-Compressed Strings. Grammar-based compression, where one replaces a long string by a small context-free grammar that generates the string, is a simple and powerful paradigm that captures many popular compression schemes. Given a grammar, the random access problem...... string. We present new data structures that achieve optimal time for updates and queries while using space linear in the size of the optimal relative compression, for nearly all combinations of parameters. We also present solutions for restricted and extended sets of updates. To achieve these results, we...... revisit the dynamic partial sums problem and the substring concatenation problem. We present new optimal or near optimal bounds for these problems. Plugging in our new results we also immediately obtain new bounds for the string indexing for patterns with wildcards problem and the dynamic text and static...

  14. String theory of the Regge intercept.

    Science.gov (United States)

    Hellerman, S; Swanson, I

    2015-03-20

    Using the Polchinski-Strominger effective string theory in the covariant gauge, we compute the mass of a rotating string in D dimensions with large angular momenta J, in one or two planes, in fixed ratio, up to and including first subleading order in the large J expansion. This constitutes a first-principles calculation of the value for the order-J(0) contribution to the mass squared of a meson on the leading Regge trajectory in planar QCD with bosonic quarks. For open strings with Neumann boundary conditions, and for closed strings in D≥5, the order-J(0) term in the mass squared is exactly calculated by the semiclassical approximation. This term in the expansion is universal and independent of the details of the theory, assuming only D-dimensional Poincaré invariance and the absence of other infinite-range excitations on the string world volume, beyond the Nambu-Goldstone bosons.

  15. Field theory of relativistic strings: I. Trees

    International Nuclear Information System (INIS)

    Kaku, M.; Kikkawa, K.

    1985-01-01

    The authors present an entirely new kind of field theory, a field theory quantized not at space-time points, but quantized along an extended set of multilocal points on a string. This represents a significant departure from the usual quantum field theory, whose free theory represents a definite set of elementary particles, because the field theory on relativistic strings can accommodate an infinite set of linearly rising Regge trajectories. In this paper, the authors (1) present canonical quantization and the Green's function of the free string, (2) introduce three-string interactions, (3) resolve the question of multiple counting, (4) complete the counting arguments for all N-point trees, and (5) introduce four-string interactions which yield a Yang-Mills structure when the zero-slope limit is taken

  16. Knotlike cosmic strings in the early universe

    Science.gov (United States)

    Duan, Yi-shi; Liu, Xin

    2004-02-01

    In this paper, the knotlike cosmic strings in the Riemann-Cartan space-time of the early universe are discussed. It has been revealed that the cosmic strings can just originate from the zero points of the complex scalar quintessence field. In these strings we mainly study the knotlike configurations. Based on the integral of Chern-Simons 3-form a topological invariant for knotlike cosmic strings is constructed, and it is shown that this invariant is just the total sum of all the self-linking and linking numbers of the knots family. Furthermore, it is also pointed out that this invariant is preserved in the branch processes during the evolution of cosmic strings.

  17. Wavy strings: Black or bright?

    International Nuclear Information System (INIS)

    Kaloper, N.; Myers, R.C.; Roussel, H.

    1997-01-01

    Recent developments in string theory have brought forth considerable interest in time-dependent hair on extended objects. This novel new hair is typically characterized by a wave profile along the horizon and angular momentum quantum numbers l,m in the transverse space. In this work, we present an extensive treatment of such oscillating black objects, focusing on their geometric properties. We first give a theorem of purely geometric nature, stating that such wavy hair cannot be detected by any scalar invariant built out of the curvature and/or matter fields. However, we show that the tidal forces detected by an infalling observer diverge at the open-quotes horizonclose quotes of a black string superposed with a vibration in any mode with l≥1. The same argument applied to longitudinal (l=0) waves detects only finite leading-order tidal forces. We also provide an example with a manifestly smooth metric, proving that at least a certain class of these longitudinal waves have regular horizons. copyright 1997 The American Physical Society

  18. Dirac strings and magnetic monopoles in the spin ice, Dy{sub 2}Ti{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Morris, David Jonathan Pryce; Czternasty, Clemens; Meissner, Michael; Rule, Kirrily; Hoffmann, Jens-Uwe; Kiefer, Klaus [Helmholtz Center for Materials and Energy, Berlin (Germany); Tennant, Alan; Klemke, Bastian [Helmholtz Center for Materials and Energy, Berlin (Germany); Technische Universitaet, Berlin (Germany); Grigera, Santiago [Instituto de Fisica de Liquidos y Sistemas Biologicos, La Plata (Argentina); Castelnovo, Claudio [University of Oxford (United Kingdom); Moessner, Roderich [Max-Planck-Institut fuer Physik komplexer Systeme, Dresden (Germany); Slobinsky, Damien [St. Andrews University (United Kingdom); Perry, Robin [University of Edinburgh (United Kingdom)

    2010-07-01

    Recent proposals in condensed matter physics that magnetic monopoles can appear as emergent quasiparticles have attracted wide levels of interest. Dirac's original picture of magnetic monopoles had them connected to strings through which magnetic flux flowed. Here we report studies into a system called Spin Ice, where spins obey ''ice rules'' of 2 spins into and 2 spins out of their tetrahedron. In these materials it has been predicted that strings of spins form via a 3D Kasteleyn transition. The geometry of spin-ice allows for net magnetic charge (magnetic monopoles) to form where ''ice rules'' are broken at the tips of the strings. Here we present three experimental pieces of evidence for these strings and magnetic monopoles.

  19. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  20. Schostakowitsch: Fünf Ballettsuiten, Suite aus Katerina Ismailova, Festliche Ouvertüre op. 96. Royal Scottisch National Orchestra, Neeme Järvi / Helge Grünewald

    Index Scriptorium Estoniae

    Grünewald, Helge

    1995-01-01

    Uuest heliplaadist "Schostakowitsch: Fünf Ballettsuiten, Suite aus Katerina Ismailova, Festliche Ouvertüre op. 96. Royal Scottisch National Orchestra, Neeme Järvi. Chandos/Koch 2 CD 700/1 (WD:114'36")

  1. Highly excited strings I: Generating function

    Directory of Open Access Journals (Sweden)

    Dimitri P. Skliros

    2017-03-01

    Full Text Available This is the first of a series of detailed papers on string amplitudes with highly excited strings (HES. In the present paper we construct a generating function for string amplitudes with generic HES vertex operators using a fixed-loop momentum formalism. We generalise the proof of the chiral splitting theorem of D'Hoker and Phong to string amplitudes with arbitrary HES vertex operators (with generic KK and winding charges, polarisation tensors and oscillators in general toroidal compactifications E=RD−1,1×TDcr−D (with generic constant Kähler and complex structure target space moduli, background Kaluza–Klein (KK gauge fields and torsion. We adopt a novel approach that does not rely on a “reverse engineering” method to make explicit the loop momenta, thus avoiding a certain ambiguity pointed out in a recent paper by Sen, while also keeping the genus of the worldsheet generic. This approach will also be useful in discussions of quantum gravity and in particular in relation to black holes in string theory, non-locality and breakdown of local effective field theory, as well as in discussions of cosmic superstrings and their phenomenological relevance. We also discuss the manifestation of wave/particle (or rather wave/string duality in string theory.

  2. String Phenomenology: Past, Present and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Alon E. Faraggi

    2014-04-01

    Full Text Available The observation of a scalar resonance at the Large Hadron Collider (LHC, compatible with perturbative electroweak symmetry breaking, reinforces the Standard Model (SM parameterisation of all subatomic data. The logarithmic evolution of the SM gauge and matter parameters suggests that this parameterisation remains viable up to the Planck scale, where gravitational effects are of comparable strength. String theory provides a perturbatively consistent scheme to explore how the parameters of the Standard Model may be determined from a theory of quantum gravity. The free fermionic heterotic string models provide concrete examples of exact string solutions that reproduce the spectrum of the Minimal Supersymmetric Standard Model. Contemporary studies entail the development of methods to classify large classes of models. This led to the discovery of exophobic heterotic-string vacua and the observation of spinor-vector duality, which provides an insight to the global structure of the space of (2,0 heterotic-string vacua. Future directions entail the study of the role of the massive string states in these models and their incorporation in cosmological scenarios. A complementary direction is the formulation of quantum gravity from the principle of manifest phase space duality and the equivalence postulate of quantum mechanics, which suggest that space is compact. The compactness of space, which implies intrinsic regularisation, may be tightly related to the intrinsic finite length scale, implied by string phenomenology.

  3. Document retrieval on repetitive string collections.

    Science.gov (United States)

    Gagie, Travis; Hartikainen, Aleksi; Karhu, Kalle; Kärkkäinen, Juha; Navarro, Gonzalo; Puglisi, Simon J; Sirén, Jouni

    2017-01-01

    Most of the fastest-growing string collections today are repetitive, that is, most of the constituent documents are similar to many others. As these collections keep growing, a key approach to handling them is to exploit their repetitiveness, which can reduce their space usage by orders of magnitude. We study the problem of indexing repetitive string collections in order to perform efficient document retrieval operations on them. Document retrieval problems are routinely solved by search engines on large natural language collections, but the techniques are less developed on generic string collections. The case of repetitive string collections is even less understood, and there are very few existing solutions. We develop two novel ideas, interleaved LCPs and precomputed document lists , that yield highly compressed indexes solving the problem of document listing (find all the documents where a string appears), top- k document retrieval (find the k documents where a string appears most often), and document counting (count the number of documents where a string appears). We also show that a classical data structure supporting the latter query becomes highly compressible on repetitive data. Finally, we show how the tools we developed can be combined to solve ranked conjunctive and disjunctive multi-term queries under the simple [Formula: see text] model of relevance. We thoroughly evaluate the resulting techniques in various real-life repetitiveness scenarios, and recommend the best choices for each case.

  4. Worldsheet factorization for twistor-strings

    International Nuclear Information System (INIS)

    Adamo, Tim

    2014-01-01

    We study the multiparticle factorization properties of two worldsheet theories which — at tree-level — describe the scattering of massless particles in four dimensions: the Berkovits-Witten twistor-string for N=4 super-Yang-Mills coupled to N=4 conformal supergravity, and the Skinner twistor-string for N=8 supergravity. By considering these string-like theories, we can study factorization at the level of the worldsheet before any Wick contractions or integrals have been performed; this is much simpler than considering the factorization properties of the amplitudes themselves. In Skinner’s twistor-string this entails the addition of worldsheet gravity as well as a formalism that represents all external states in a manifestly symmetric way, which we develop explicitly at genus zero. We confirm that the scattering amplitudes of Skinner’s theory, as well as the gauge theory amplitudes for the planar sector of the Berkovits-Witten theory, factorize appropriately at genus zero. In the non-planar sector, we find behavior indicative of conformal gravity in the Berkovits-Witten twistor-string. We contrast factorization in twistor-strings with the story in ordinary string theory, and also make some remarks on higher genus factorization and disconnected prescriptions

  5. Worldsheet factorization for twistor-strings

    Energy Technology Data Exchange (ETDEWEB)

    Adamo, Tim [Department of Applied Mathematics & Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2014-04-10

    We study the multiparticle factorization properties of two worldsheet theories which — at tree-level — describe the scattering of massless particles in four dimensions: the Berkovits-Witten twistor-string for N=4 super-Yang-Mills coupled to N=4 conformal supergravity, and the Skinner twistor-string for N=8 supergravity. By considering these string-like theories, we can study factorization at the level of the worldsheet before any Wick contractions or integrals have been performed; this is much simpler than considering the factorization properties of the amplitudes themselves. In Skinner’s twistor-string this entails the addition of worldsheet gravity as well as a formalism that represents all external states in a manifestly symmetric way, which we develop explicitly at genus zero. We confirm that the scattering amplitudes of Skinner’s theory, as well as the gauge theory amplitudes for the planar sector of the Berkovits-Witten theory, factorize appropriately at genus zero. In the non-planar sector, we find behavior indicative of conformal gravity in the Berkovits-Witten twistor-string. We contrast factorization in twistor-strings with the story in ordinary string theory, and also make some remarks on higher genus factorization and disconnected prescriptions.

  6. String-Corrected Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, V.

    2005-01-12

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.

  7. The birth of string theory

    CERN Document Server

    Castellani, Elena; Colomo, Filippo; Di Vecchia, Paolo

    2012-01-01

    String theory is currently the best candidate for a unified theory of all forces and all forms of matter in nature. As such, it has become a focal point for physical and philosophical discussions. This unique book explores the history of the theory's early stages of development, as told by its main protagonists. The book journeys from the first version of the theory (the so-called dual resonance model) in the late sixties, as an attempt to describe the physics of strong interactions outside the framework of quantum field theory, to its reinterpretation around the mid-seventies as a quantum theory of gravity unified with the other forces, and its successive developments up to the superstring revolution in 1984. Providing important background information to current debates on the theory, this book is essential reading for students and researchers in physics, as well as historians and philosophers of science.

  8. Graviton spectra in string cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Galluccio, Massimo [Osservatorio Astronomico di Roma (Roma-IT); Litterio, Marco [Istituto Astronomico dell' Universita (Roma-IT); Occhionero, Franco [Osservatorio Astronomico di Roma (Roma-IT)

    1996-08-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an ω³ increase and initiates an ω⁻⁷ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre-Big Bang) and the expanding inflationary era (or post-Big Bang). We evaluate both analytically and numerically the frequency and the intensity of the peak and we show that they may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak is at variance with ordinarily monotonic (either increasing or decreasing) graviton spectra of canonical cosmologies; its detection would therefore offer strong support to string cosmology.

  9. Optimal shapes of compact strings

    International Nuclear Information System (INIS)

    Maritan, A.; Micheletti, C.; Trovato, A.; Banavar, J.R.

    2000-07-01

    Optimal geometrical arrangements, such as the stacking of atoms, are of relevance in diverse disciplines. A classic problem is the determination of the optimal arrangement of spheres in three dimensions in order to achieve the highest packing fraction; only recently has it been proved that the answer for infinite systems is a face-centred-cubic lattice. This simply stated problem has had a profound impact in many areas, ranging from the crystallization and melting of atomic systems, to optimal packing of objects and subdivision of space. Here we study an analogous problem-that of determining the optimal shapes of closely packed compact strings. This problem is a mathematical idealization of situations commonly encountered in biology, chemistry and physics, involving the optimal structure of folded polymeric chains. We find that, in cases where boundary effects are not dominant, helices with a particular pitch-radius ratio are selected. Interestingly, the same geometry is observed in helices in naturally-occurring proteins. (author)

  10. Whiteheadian Actual Entitities and String Theory

    Science.gov (United States)

    Bracken, Joseph A.

    2012-06-01

    In the philosophy of Alfred North Whitehead, the ultimate units of reality are actual entities, momentary self-constituting subjects of experience which are too small to be sensibly perceived. Their combination into "societies" with a "common element of form" produces the organisms and inanimate things of ordinary sense experience. According to the proponents of string theory, tiny vibrating strings are the ultimate constituents of physical reality which in harmonious combination yield perceptible entities at the macroscopic level of physical reality. Given that the number of Whiteheadian actual entities and of individual strings within string theory are beyond reckoning at any given moment, could they be two ways to describe the same non-verifiable foundational reality? For example, if one could establish that the "superject" or objective pattern of self- constitution of an actual entity vibrates at a specific frequency, its affinity with the individual strings of string theory would be striking. Likewise, if one were to claim that the size and complexity of Whiteheadian 'societies" require different space-time parameters for the dynamic interrelationship of constituent actual entities, would that at least partially account for the assumption of 10 or even 26 instead of just 3 dimensions within string theory? The overall conclusion of this article is that, if a suitably revised understanding of Whiteheadian metaphysics were seen as compatible with the philosophical implications of string theory, their combination into a single world view would strengthen the plausibility of both schemes taken separately. Key words: actual entities, subject/superjects, vibrating strings, structured fields of activity, multi-dimensional physical reality.

  11. Planckian axions in string theory

    International Nuclear Information System (INIS)

    Bachlechner, Thomas C.; Long, Cody; McAllister, Liam

    2015-01-01

    We argue that super-Planckian diameters of axion fundamental domains can arise in Calabi-Yau compactifications of string theory. In a theory with N axions θ i , the fundamental domain is a polytope defined by the periodicities of the axions, via constraints of the form −π√N. This result is robust in the presence of P>N constraints, while for P=N the diameter is further enhanced by eigenvector delocalization to N 3/2 f N . We directly verify our results in explicit Calabi-Yau compactifications of type IIB string theory. In the classic example with h 1,1 =51 where parametrically controlled moduli stabilization was demonstrated by Denef et al. in http://dx.doi.org/10.4310/ATMP.2005.v9.n6.a1, the largest metric eigenvalue obeys f N ≈0.013M pl . The random matrix analysis then predicts, and we exhibit, axion diameters ≈M pl for the precise vacuum parameters found in http://dx.doi.org/10.4310/ATMP.2005.v9.n6.a1. Our results provide a framework for pursuing large-field axion inflation in well-understood flux vacua.

  12. String gravity and cosmology some new ideas

    CERN Document Server

    Kiritsis, Elias; Kiritsis, Elias; Kounnas, Costas

    1997-01-01

    String theory provides the only consistent framework so far that unifies all interactions including gravity. We discuss gravity and cosmology in string theory. Conventional notions from general relativity like geometry, topology etc. are well defined only as low energy approximations in string theory. At small distances physics deviates from the field theoretic intuition. We present several examples of purely stringy phenomena which imply that the physics at strong curvatures can be quite different from what one might expect from field theory. They indicate new possibilities in the context of quantum cosmology.

  13. Systems and methods for photovoltaic string protection

    Energy Technology Data Exchange (ETDEWEB)

    Krein, Philip T.; Kim, Katherine A.; Pilawa-Podgurski, Robert C. N.

    2017-10-25

    A system and method includes a circuit for protecting a photovoltaic string. A bypass switch connects in parallel to the photovoltaic string and a hot spot protection switch connects in series with the photovoltaic string. A first control signal controls opening and closing of the bypass switch and a second control signal controls opening and closing of the hot spot protection switch. Upon detection of a hot spot condition the first control signal closes the bypass switch and after the bypass switch is closed the second control signal opens the hot spot protection switch.

  14. Quantum consistency of open string theories

    International Nuclear Information System (INIS)

    Govaerts, J.

    1989-01-01

    We discuss how Virasoro anomalies in open string theories uniquely select the gauge group SO(2 D/2 ) independently of any regularisation, although the cancellation of these anomalies does not occur in tachyonic theories, and regulators can always be chosen to make these theories (one-loop) finite for any SO(n) and USp(n) gauge group. The discussion is mainly restricted to open bosonic strings. These results open new perspectives for the recent suggestion made by Sagnotti, the generalisations of which allow for the construction of new open string theories in less than ten dimensions. (orig.)

  15. A non-perturbative approach to strings

    International Nuclear Information System (INIS)

    Orland, P.

    1986-03-01

    After briefly reviewing the theory of strings in the light-cone gauge, a lattice regularized path integral for the amplitudes is discussed. The emphasis is put on a toy string model; the U(N) Veneziano model in the limit as N->infinite with g 0 2 N fixed. The lattice methods of Giles and Thorn are used extensively, but are found to require modification beyond perturbation theory. The twenty-six-dimensional toy string model is recast as a two-dimensional spin system. (orig.)

  16. Open string decoupling and tachyon condensation

    International Nuclear Information System (INIS)

    Chalmers, G.

    2001-01-01

    The amplitudes in perturbative open string theory are examined as functions of the tachyon condensate parameter. The boundary state formalism demonstrates the decoupling of the open string modes at the non-perturbative minima of the tachyon potential via a degeneration of open world-sheets and identifies an independence of the coupling constants g s and g YM at general values of the tachyon condensate. The closed sector is generated at the quantum level; it is also generated at the classical level through the condensation of the propagating open string modes on the D-brane degrees of freedom.

  17. The String and the Cosmic Bounce

    Directory of Open Access Journals (Sweden)

    Bozza V.

    2014-04-01

    Full Text Available String theory introduces a new fundamental scale (the string length that is expected to regularize the singularities of classical general relativity. In a cosmological context, the Big Bang is no longer regarded as the beginning of time, but just a transition between a Pre-Big Bang collapse phase and the current expansion. We will review old and recent attempts to build consistent bouncing cosmologies inspired to string theories, discussing their solved and unsolved problems, focussing on the observables that may distinguish them from standard inflationary scenarios.

  18. A hybrid metaheuristic for closest string problem.

    Science.gov (United States)

    Mousavi, Sayyed Rasoul

    2011-01-01

    The Closest String Problem (CSP) is an optimisation problem, which is to obtain a string with the minimum distance from a number of given strings. In this paper, a new metaheuristic algorithm is investigated for the problem, whose main feature is relatively high speed in obtaining good solutions, which is essential when the input size is large. The proposed algorithm is compared with four recent algorithms suggested for the problem, outperforming them in more than 98% of the cases. It is also remarkably faster than all of them, running within 1 s in most of the experimental cases.

  19. Big bang models in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes Pleinlaan 2, B-1050 Brussels (Belgium)

    2006-11-07

    These proceedings are based on lectures delivered at the 'RTN Winter School on Strings, Supergravity and Gauge Theories', CERN, 16-20 January 2006. The school was mainly aimed at PhD students and young postdocs. The lectures start with a brief introduction to spacetime singularities and the string theory resolution of certain static singularities. Then they discuss attempts to resolve cosmological singularities in string theory, mainly focusing on two specific examples: the Milne orbifold and the matrix big bang.

  20. String Analysis as an Abstract Interpretation

    Science.gov (United States)

    Kim, Se-Won; Choe, Kwang-Moo

    We formalize a string analysis within abstract interpretation framework. The abstraction of strings is given as a conjunction of predicates that describes the common configuration changes on the reference pushdown automaton while processing the strings. We also present a family of pushdown automata called ɛ bounded pushdown automata. This family covers all context-free languages, and by using this family of pushdown automata, we can prevent abstract values from becoming infinite conjunctions and guarantee that the operations required in the analyzer are computable.

  1. Affinity Strings: Enterprise Data for Resource Recommendations

    Directory of Open Access Journals (Sweden)

    Shane Nackerud

    2008-12-01

    Full Text Available The University of Minnesota Libraries have created a MyLibrary portal, with databases and e-journals targeted to users, based on their affiliations. The University's enterprise authentication system provides an "affinity string", now used to personalize the MyLibrary portal. This affinity string automates discovery of a user's relationship to the University--describing a user's academic department and degree program or position at the University. Affinity strings also provide the Libraries with an anonymized view of resource usage, allowing data collection that respects users' privacy and lays the groundwork for automated recommendation of relevant resources based on the practices and habits of their peers.

  2. A gluing operator for the ambitwistor string

    Science.gov (United States)

    Roehrig, Kai A.; Skinner, David

    2018-01-01

    We present a new operator in the ambitwistor string which glues together correlators with fewer points or of lower genus. It underpins the recursive construction of tree-level CHY scattering amplitudes by Dolan & Goddard, as well as the computation of loop integrands on a Riemann sphere by Geyer et al. The gluing operator is a tractable object due to the finiteness of the spectrum. In particular, we demonstrate how it gives rise to the complete one-loop integrand in SYM and SUGRA. The operator is conjectured to be the path integral incarnation of the ambitwistor string propagator, and to coincide with the field theory limit of the standard string theory propagator.

  3. Observation of Motion of Bowed Strings and Resonant Strings in Violin Performances

    Science.gov (United States)

    Matsutani, Akihiro

    2013-10-01

    The motion of a bowed string and a resonant string of a violin were simultaneously observed for the first time. The results of the direct observation of string motion in double stops and harmonics are also presented. The importance of the resonance was experimentally demonstrated from these observations. It is suggested that players should take account of the resonance and ideal Helmholtz motion in violin performances.

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... liver disease are at greater risk for worsening liver failure after TIPS. If your liver failure is severe, a TIPS may not be the ... children are more likely to be performed before liver transplant in those with ascites or variceal ... 08, 2017 Send us your feedback Did you find the ...

  5. Advances in String Theory in Curved Backgrounds: A Synthesis Report

    OpenAIRE

    Sanchez, Norma G.

    2003-01-01

    A synthetic report of the advances in the study of classical and quantum string dynamics in curved backgrounds is provided, namely: the new feature of multistring solutions; the effect of a cosmological constant and of spacial curvature on classical and quantum strings; classical splitting of fundamental strings;the general string evolution in constant curvature spacetimes;the conformal invariant effects;strings on plane waves, shock waves and spacetime singularities and its spectrum. New dev...

  6. Multi-branes boundary states with open string interactions

    International Nuclear Information System (INIS)

    Pesando, Igor

    2008-01-01

    We derive boundary states which describe configurations of multiple parallel branes with arbitrary open string states interactions in bosonic string theory. This is obtained by a careful discussion of the factorization of open/closed string states amplitudes taking care of cycles needed by ensuring vertices commutativity: in particular the discussion reveals that already at the tree level open string knows of the existence of closed string

  7. Hagedorn Behavior of Little String Theories from string corrections to NS5-branes

    DEFF Research Database (Denmark)

    Harmark, Troels; Obers, N. A.

    2000-01-01

    We examine the Hagedorn behavior of little string theory using its conjectured duality with near-horizon NS5-branes. In particular, by studying the string-corrected NS5-brane supergravity solution, it is shown that tree-level corrections to the temperature vanish, while the leading one-loop string...... correction generates the correct temperature dependence of the entropy near the Hagedorn temperature. Finally, the Hagedorn behavior of ODp-brane theories, which are deformed versions of little string theory, is considered via their supergravity duals....

  8. Closed string fields as parameters of extra gauge symmetry of open string field theory

    International Nuclear Information System (INIS)

    Aref'eva, I. Ya.; Chekhov, L.O.

    1987-05-01

    A gauge invariant action for mixed system of closed and open bosonic strings is considered. We notice that in the open string sector a gauge group parametrized by closed string states does act. In the description of mixed system the open-to-closed transition operator plays a crucial role. We show that this transition operator is an intertwining operator between BRST charges for closed and open string. The closed-open-open analogue of Caneschi-Schwimmer-Veneziano amplitude is presented and the triple application of the transition operator to all the tree legs of the open CVS vertex is also discussed. (author). 20 refs, 3 figs

  9. MUSICAL INTERPRETATION OF THE POETIC SOURCE IN THE RAP POEM FROM THE VOCAL-SYMPHONIC CYCLE FOR BARITONE AND ORCHESTRA APRÈS UNE LECTURE BY GHENADIE CIOBANU

    Directory of Open Access Journals (Sweden)

    CIOBANU-SUHOMLIN IRINA

    2017-06-01

    Full Text Available The author considers the peculiarities of the interpretation of the poetic text in the music of one of the poems of the vocal and symphonic cycle for baritone and orchestra „Après une Lecture” by Ghenadie Ciobanu. The purpose of the article is to reveal the specific features of the musical and poetic synthesis achieved by the composer in the „Rap Poem”: in the description of the genre basis of the poetic and musical works, their figurative content, the correlation of their syntax, the specific musical intonation of the poetic text, the role of the orchestra. The composer’s method of working with a word is evaluated from the novelty standpoint, and the final artistic result is determined from the position of its stylistic affiliation as a musical exemple of the „third direction” in the music of the 20th century.

  10. Quark mass correction to the string potential

    International Nuclear Information System (INIS)

    Lambiase, G.; Nesterenko, V.V.

    1995-01-01

    A consistent method for calculating the interquark potential generated by the relativistic string with massive ends is proposed. In this approach the interquark potential in the model of the Nambu-Goto string with point-like masses at its ends is calculated. At first the calculation is done in the one-loop approximation and then the variational estimation is performed. The quark mass correction results in decreasing the critical distance (deconfinement radius). When quark mass decreases the critical distance also decreases. For obtaining a finite result under summation over eigenfrequencies of the Nambu-Goto string with massive ends a suitable mode-by-mode subtraction is proposed. This renormalization procedure proves to be completely unique. In the framework of the developed approach the one-loop interquark potential in the model of the relativistic string with rigidity is also calculated. 34 refs., 2 figs

  11. Renormalizability of Open Bosonic Thermal Strings

    OpenAIRE

    Haruo, FUJISAKI; Koichi, NAKAGAWA; Department of Physics, Rikkyo University; Department of Physics, Rikkyo University

    1989-01-01

    The thermal stability of renormalization of open bosonic strings is exemplified through the Neveu-Scherk regularization of the planar tachyon self-energy within the framework of the thermofield dynamics.

  12. Gauge/string duality and hadronic physics

    OpenAIRE

    Boschi-Filho, Henrique; Braga, Nelson R. F.

    2006-01-01

    We review some recent results on phenomenological approaches to strong interactions inspired in gauge/string duality. In particular, we discuss how such models lead to very good estimates for hadronic masses.

  13. Introduction to string and superstring theory II

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1987-03-01

    Conformal field theory is reviewed, then conformal invariance is used to rederive the basic results on the embedding dimensionality for bosonic and fermionic strings. The spectrum of the bosonic and the computation of scattering amplitudes are discussed. The formalism used is extended to clarify the origin of Yang-Mills gauge invariance in the open bosonic string theory. The question of the general-coordinate gauge invariance of string theory is addressed, presenting two disparate viewpoints on this question. A brief introduction is then given of the reduction from the idealized string theory in 10 extended dimensions to more realistic solutions in which all but 4 of these dimensions are compactified. The state of knowledge about the space-time supersymmetry of the superstring from the covariant viewpoint is outlined. An approach for identifying possible 6-dimensional spaces which might represent the form of the compact dimensions is discussed, and the orbifold scheme of compactification is presented. 77 refs., 18 figs

  14. Instantons, hypermultiplets and the heterotic string

    International Nuclear Information System (INIS)

    Halmagyi, Nick; Melnikov, Ilarion V.; Sethi, Savdeep

    2007-01-01

    Hypermultiplet couplings in type IIA string theory on a Calabi-Yau space can be quantum corrected by D2-brane instantons wrapping special Lagrangian cycles. On the other hand, hypermultiplet couplings in the heterotic string on a K3 surface are corrected by world-sheet instantons wrapping curves. In a class of examples, we relate these two sets of instanton corrections. We first present an analogue of the c-map for the heterotic string via a dual flux compactification of M-theory. Using this duality, we propose two ways of capturing quantum corrections to hypermultiplets. We then use the orientifold limit of certain F-theory compactifications to relate curves in K3 to special Lagrangians in dual type IIA compactifications. We conclude with some results from perturbative string theory for hypermultiplet F-terms and a conjecture about the topology of brane instantons

  15. Pinching parameters for open (super) strings

    Science.gov (United States)

    Playle, Sam; Sciuto, Stefano

    2018-02-01

    We present an approach to the parametrization of (super) Schottky space obtained by sewing together three-punctured discs with strips. Different cubic ribbon graphs classify distinct sets of pinching parameters; we show how they are mapped onto each other. The parametrization is particularly well-suited to describing the region within (super) moduli space where open bosonic or Neveu-Schwarz string propagators become very long and thin, which dominates the IR behaviour of string theories. We show how worldsheet objects such as the Green's function converge to graph theoretic objects such as the Symanzik polynomials in the α ' → 0 limit, allowing us to see how string theory reproduces the sum over Feynman graphs. The (super) string measure takes on a simple and elegant form when expressed in terms of these parameters.

  16. Casimir energy for a piecewise uniform string

    International Nuclear Information System (INIS)

    Brevik, I.; Nielsen, H.B.

    1989-07-01

    The Casimir energy for the transverse oscillations of a piecewise uniform closed string is calculated. The string consists of two parts I and II, endowed in general with different tensions and mass densities, although adjusted in such a way that the velocity of sound always equals the velocity of light. The dispersion equation is worked out under general conditions, and the frequency spectrum is determined in special cases. When the ratio L II /L I between the string lengths is an integer, it is in principle possible to determine the frequency spectrum through solving algebraic equations of increasingly high degree. The Casimir energy relative to the uniform string is in general found to be negative, although in the special case L I =L II the energy is equal to zero. Delicate points in the regularization procedure are discussed; they point toward an anomaly in the theory. (orig.)

  17. Matrix Models and String World Sheet Duality

    OpenAIRE

    de Alwis, S. P.

    1997-01-01

    The scaling limit used recently to derive matrix models, and a certain analyticity assumption, are invoked to argue that the agreement between some matrix model calculations and supergravity is a consequence of string world sheet duality.

  18. The dual faces of string theory

    CERN Document Server

    Kiritsis, Elias

    1993-01-01

    Duality symmetries for strings moving in non-trivial spacetime backgrounds are analysed. It is shown that, for backgrounds generated from compact WZW and coset models, such duality symmetries are exact to all orders in string perturbation theory. A global treatment of duality symmetries is given, by associating them to the known symmetries of affine current algebras (affine-Weyl group and external automorphisms). It is argued that self-duality symmetries of WZW and coset models generate the duality symmetries of their moduli space. Some remarks are presented, concerning the survival of such symmetries in the non-compact case. The implications of duality symmetries for string dynamics in non-trivial/singular spacetimes are discussed. (Talk given at the "Strings 93" Conference at Berkeley, May 1993)

  19. Witten Genus and String Complete Intersections

    OpenAIRE

    Chen, Qingtao; Han, Fei

    2006-01-01

    In this note, we prove that the Witten genus of nonsingular string complete intersections in product of complex projective spaces vanishes. Our result generalizes a known result of Landweber and Stong (cf. [HBJ]).

  20. Academic Training: String Theory for Pedestrians

    CERN Multimedia

    2007-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 29, 30, 31 January 2007, from 11:00 to 12:00 Main Auditorium, bldg. 500 on 29 and 30 January, TH Auditorium, Bldg 4, 3-006, on 31 January String Theory for Pedestrians B. ZWIEBACH, MIT, Cambridge, USA In this 3-lecture series I will discuss the basics of string theory, some physical applications, and the outlook for the future. I will begin with the main concepts of the classical theory and the application to the study of cosmic superstrings. Then I will turn to the quantum theory and discuss applications to the investigation of hadronic spectra and the recently discovered quark-gluon plasma. I will conclude with a sketch of string models of particle physics and showing some avenues that may lead to a complete formulation of string theory.