Inflation, string theory and cosmic strings

Chernoff, David F.; Tye, S.‐H. Henry

doi:10.1142/s0218271815300104

Cited by 40 publications

(67 citation statements)

References 147 publications

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“…In addition, advances in string theory naturally yield superstrings, stringlike entities which can have much smaller μ. In this context, Chernoff and Tye [4] suggested that one look for the transient change of the unresolved flux when a star passes behind the string. A search for superstrings by string microlensing is conceptually similar to the search for Newtonian masses by way of normal microlensing.…”

Section: String Lensing Basicsmentioning

confidence: 99%

“…String theory, the best-developed tool to explore this epoch, suggests the birth and survival of a network of one-dimensional structures on cosmological scales [3]. Numerous fossil remnants of these cosmic superstrings may exist within the galaxy, which could be revealed through the optical lensing of background stars by way of the technique of microlensing [4]. This paper investigates the fundamental physical features of microlensing relevant to optical searches for string loops generated by the network.…”

Section: Introductionmentioning

confidence: 99%

“…By investigating a detailed model of the tension-dependent distribution of loops within our galaxy [16], it was found that the local enhancement of string loops has implications for microlensing searches, gravitational wave detection experiments and for pulsar timing measurements. In this paper, we concentrate on microlensing.…”

Section: Introductionmentioning

confidence: 99%

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Cosmic string loop microlensing

Bloomfield

Chernoff

2014

Phys. Rev. D

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Cosmic superstring loops within the galaxy microlens background point sources lying close to the observer-string line of sight. For suitable alignments, multiple paths coexist and the (achromatic) flux enhancement is a factor of two. We explore this unique type of lensing by numerically solving for geodesics that extend from source to observer as they pass near an oscillating string. We characterize the duration of the flux doubling and the scale of the image splitting. We probe and confirm the existence of a variety of fundamental effects predicted from previous analyses of the static infinite straight string: the deficit angle, the Kaiser-Stebbins effect, and the scale of the impact parameter required to produce microlensing. Our quantitative results for dynamical loops vary by Oð1Þ factors with respect to estimates based on infinite straight strings for a given impact parameter. A number of new features are identified in the computed microlensing solutions. Our results suggest that optical microlensing can offer a new and potentially powerful methodology for searches for superstring loop relics of the inflationary era.

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Section: String Lensing Basicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cosmic string loop microlensing

Bloomfield

Chernoff

2014

Phys. Rev. D

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“…A topic which has received increasing attention is related to string-theoretical models of dS spacetime and inflation. Recently several constructions of metastable dS vacua within the framework of string theory are discussed (see, for instance, reviews [12,13]). …”

Section: Introductionmentioning

confidence: 99%

“…The cosmic superstrings, which are fundamental quantum strings stretched to cosmological scales, were first considered in [26]. More recently, a mechanism for the generation of this type of objects with low values of the string tensions is proposed within the framework of brane inflationary models [13,22,23,27]. In these models the accelerated expansion of the universe is a consequence of the motion of branes in warped and compact extra dimensions.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic vacuum fluctuations around a cosmic string in de Sitter spacetime

2017

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The electromagnetic field correlators are evaluated around a cosmic string in background of (D + 1)-dimensional dS spacetime assuming that the field is prepared in the Bunch-Davies vacuum state. The correlators are presented in the decomposed form where the string-induced topological parts are explicitly extracted. With this decomposition, the renormalization of the local vacuum expectation values (VEVs) in the coincidence limit is reduced to the one for dS spacetime in the absence of the cosmic string. The VEVs of the squared electric and magnetic fields, and of the vacuum energy density are investigated. Near the string they are dominated by the topological contributions and the effects induced by the background gravitational field are small. In this region, the leading terms in the topological contributions are obtained from the corresponding VEVs for a string on the Minkowski bulk multiplying by the conformal factor. At distances from the string larger than the curvature radius of the background geometry, the pure dS parts in the VEVs dominate. In this region, for spatial dimensions D > 3, the influence of the gravitational field on the topological contributions is crucial and the corresponding behavior is essentially different from that for a cosmic string on the Minkowski bulk. There are well-motivated inflationary models which produce cosmic strings. We argue that, as a consequence of the quantum-to-classical transition of super-Hubble electromagnetic fluctuations during inflation, in the post-inflationary era these strings will be surrounded by large-scale stochastic magnetic fields. These fields could be among the distinctive features of the cosmic strings produced during the inflation and also of the corresponding inflationary models.

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Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate Supermassive Black Holes in the Early Universe?

Lake

Harkó

2017

Fortschritte der Physik

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The discovery of a large number of supermassive black holes (SMBH) at redshifts z > 6, when the Universe was only 900 million years old, raises the question of how such massive compact objects could form in a cosmologically short time interval. Each of the standard scenarios proposed, involving rapid accretion of seed black holes or black hole mergers, faces severe theoretical difficulties in explaining the short-time formation of supermassive objects. In this work we propose an alternative scenario for the formation of SMBH in the early Universe, in which energy transfer from superconducting cosmic strings piercing small seed black holes is the main physical process leading to rapid mass increase. As a toy model, the accretion rate of a seed black hole pierced by two antipodal strings carrying constant current is considered. Using an effective action approach, which phenomenologically incorporates a large class of superconducting string models, we estimate the minimum current required to form SMBH with masses of order M = 2 × 10 9 M⊙ by z = 7.085. This corresponds to the mass of the central black hole powering the quasar ULAS J112001.48+064124.3 and is taken as a test case scenario for early-epoch SMBH formation. For GUT scale strings, the required fractional increase in the string energy density, due to the presence of the current, is of order 10 −7 , so that their existence remains consistent with current observational bounds on the string tension. In addition, we consider an "exotic" scenario, in which an SMBH is generated when a small seed black hole is pierced by a higher-dimensional F −string, predicted by string theory. We find that both topological defect strings and fundamental strings are able to carry currents large enough to generate early-epoch SMBH via our proposed mechanism.

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Inflation, string theory and cosmic strings

Cited by 40 publications

References 147 publications

Cosmic string loop microlensing

Cosmic string loop microlensing

Electromagnetic vacuum fluctuations around a cosmic string in de Sitter spacetime

Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate Supermassive Black Holes in the Early Universe?

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