arXiv subjects

Kamal L. Panigrahi

Publications and source records attributed to Kamal L. Panigrahi.

At least 37 records · Page 2Linked to original sources

arXiv2018

Spinning pulsating strings in $(AdS_5 \times S^5)_{\varkappa}$

We study a general class of spinning pulsating strings in $(AdS_5 \times S^5)_{\varkappa}$ background. For these family of solitons, we examine the scaling relation between the energy, spin or angular momentum. We verify that in $\varkappa \rightarrow 0 $ limit these relations reduce to the undeformed $AdS_5 \times S^5$ case. We further study an example of a string which is spinning in the $\varkappa$-deformed AdS$_5$ and S$^5$ simultaneously and find out the scaling relation among various conserved charges.

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arXiv2017

Perturbations of spiky strings in flat spacetimes

Perturbations of a class of semiclassical strings known today as spiky strings, are studied using the well-known Jacobi equations for small normal deformations of an embedded timelike surface. It is shown that there exists finite normal perturbations of the spiky string worldsheets embedded in a $2+1$ dimensional flat spacetime. Such perturbations lead to a rounding off of the spikes, which, in a way, demonstrates the stable nature of the unperturbed worldsheet. The same features appear for the dual spiky string solution and in the spiky as well as their dual solutions in $3+1$ dimensional flat spacetime. Our results are based on exact solutions of the corresponding Jacobi equations which we obtain and use while constructing the profiles of the perturbed configurations.

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arXiv2016

$SL(2, Z)$ invariant rotating $(m,n)$ strings in $AdS_3\times S^3$ with mixed flux

We study rigidly rotating and pulsating $(m,n)$ strings in $AdS_3 \times S^3$ with mixed three form flux. The $AdS_3 \times S^3$ background with mixed three form flux is obtained in the near horizon limit of $SL(2,Z)$-transformed solution, corresponding to the bound state of NS5-branes and fundamental strings. We study the probe $(m,n)-$string in this background by solving the manifest $SL(2,Z)-$covariant form of the action. We find out the dyonic giant magnon and single spike solutions corresponding to the equations of motion of a probe string in this background and find out various relationships among the conserved charges. We further study a class of pulsating $(m,n)$ string in $AdS_3$ with mixed three form flux.

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arXiv2016

On circular strings in $(AdS_3 \times S^3)_{\varkappa}$

The so called one-parameter (often called $\varkappa$) deformed $AdS$ string sigma models have attracted a lot of attention lately in the study of integrability in string theory. We construct various circular string solutions in the $(AdS_3 \times S^3)_{\varkappa}$ background and describe the characteristics of such solutions qualitatively. We study the Bohr-Sommerfeld like quantization for these string states to characterise the motion. Further we find a `long' string limit of such circular strings in the $\varkappa$-deformed $AdS_3$ and find a novel dependence of the oscillation number on the energy in the next to leading order expansion.

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arXiv2016

Chaos in classical string dynamics in $\hatγ$ deformed $AdS_5 \times T^{1,1}$

We consider a circular string in $\hatγ$ deformed $AdS_5 \times T^{1,1}$ which is localized in the center of $AdS_5$ and winds around the two circles of deformed $T^{1,1}$. We observe chaos in the phase space of the circular string implying non-integrability of string dynamics. The chaotic behaviour in phase space is controlled by energy as well as the deforming parameter $\hatγ$. We further show that the point like object exhibits non-chaotic behaviour. Finally we calculate the Lyapunov exponent for both extended and point like object in support of our first result.

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arXiv2015

A note on oscillating strings in $AdS_3 \times S^3$ with mixed three-form fluxes

We present a detailed study of the pulsating string solutions in AdS3 x S3 supported by both RR and NS-NS fluxes. This background has recently been proved to be integrable. We find the dispersion relation between the energy, oscillation number and other conserved charges when the NS-NS flux turned on is small. We further discuss the fate of the string solutions in pure RR and NS-NS cases.

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arXiv2015

Spiky strings in $\varkappa$-deformed $AdS$

We study rigidly rotating strings in $\varkappa$-deformed $AdS$ background. We probe this classically integrable background with `spiky' strings and analyze the string profiles in the large charge limit systematically. We also discuss the dispersion relation among the conserved charges for these solutions in long string limit.

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arXiv2014

Pulsating strings on $(AdS_3 \times S^3)_\varkappa$

We derive the energy of pulsating strings as a function of adiabatic invariant oscillation number, which oscillates in $S^2_{\varkappa}$. We find similar solutions for the strings oscillating in deformed $AdS_3$. Furthermore, we generalize the result to the oscillating strings in anti-de Sitter space in the presence of extra angular momentum in $(AdS_3 \times S^1)_\varkappa$.

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arXiv2014

Rotating and Orbiting Strings in Dp-brane background

We probe the open fundamental strings in Dp-brane (p=1, 3, 5) backgrounds and find new classes of rotating and orbiting string solutions. We show that for various worldsheet embedding ansatz we get solutions of the string equations of motion that correspond to the well known giant magnon and single spikes, in addition to few new solutions corresponding to the orbiting strings. We make a systematic study of both rigidly rotating and orbiting strings in D1, D3 and D5-brane backgrounds.

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arXiv2014

Spiky strings on AdS3 x S3 with NS-NS flux

We study rigidly rotating strings in the background of AdS3 x S3 with Neveu-Schwarz (NS) fluxes. We find two interesting limiting cases corresponding to the known giant magnon and the new single spike solution of strings in the above background and write down the dispersion relations among various conserved charges. We use proper regularization to find the correct relations among them. We further study the circular and infinite spiky strings on AdS and study their properties.

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arXiv2014

Semiclassical Strings in Supergravity PFT

Puff Field Theory (PFT) is an example of a non-local field theory which arises from a novel embedding of D-branes in 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 nonlocal spacetime by applying a Penrose limit and comment on its similarity with the maximally supersymmetric PP-wave background.

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arXiv2014

On the Rotating and Oscillating strings in $(AdS_3\times S^3)_{\varkappa}$

We study rigidly rotating strings in the $\varkappa$-deformed $AdS_3 \times S^3$ background. We find out two classes of solutions corresponding to the giant magnon and single spike solutions of the string rotating in two $S^2_{\varkappa}$ subspace of rotations reduced along two different isometries. We verify that the dispersion relations reduce to the well known relation in the $\varkappa\rightarrow 0$ limit. We further study some oscillating string solutions in the $S^3_{\varkappa}$ subspace.

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arXiv2013

Pulsating Strings With Angular Momenta

We derive the energy of pulsating string, as function of oscillation number and angular momenta, which oscillates in AdS3 with an extra angular momentum along S1. We find similar solutions for the strings oscillating in S3 in addition to extra angular momentum. Further we generalize the result of the oscillating strings in Anti de-Sitter space in the presence of both spin and angular momentum in AdS5 x S1.

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arXiv2012

Mass Deformed L-BLG Theory From ABJ Theory

We construct mass deformed SU(N) L-BLG theory together with $U(M-N)_k$ Chern-Simons theory. This mass deformed L-BLG theory is a low energy world volume theory of a stack of $N$ number of M2-brane far away from $C^4/Z_k$ singularity. We carry out this by defining a special scaling limit of the fields of this theory and simultaneously sending the Chern-Simons level to infinity.

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arXiv2012

On Rotating and Oscillating Four-Spin Strings in AdS5 X S5

We study rigidly rotating strings in AdS5 X S5 background with one spin along AdS5 and three angular momenta along S5. We find dispersion relations among various charges and interpret them as giant magnon and spiky string solutions in various limits. Further we present an example of oscillating string which oscillates in the radial direction of the AdS5 and at the same time rotates in S5.

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arXiv2012

On the D-brane solutions in Godel Universe

We present a class of supersymmetric Godel solutions in string theory from the non-standard intersection of branes in supergravities. Such solutions are obtained by applying a T-duality on the known solutions in PP-wave spacetime. We further present classical solutions of supersymmetric D-brane in Godel universes arising from the PP-wave in the near horizon geometry of stack of D5-branes and from the new isometries of H_6 PP-wave background. These branes are supported by multiple constant Neveu-Schwarz and Ramond-Ramond field strengths.

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arXiv2012

Spiky Strings on I-brane

We study rigidly rotating strings in the near horizon geometry of the 1+1 dimensional intersection of two orthogonal stacks of NS5-branes, the so called I-brane background. We solve the equations of motion of the fundamental string action in the presence of two form NS-NS fluxes that the I-brane background supports and write down general form of conserved quantities. We further find out two limiting cases corresponding to giant magnon and single spike like strings in various parameter space of solutions.

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arXiv2012

Three Spin Spiky Strings in beta-deformed Background

We study rigidly rotating strings in $β$-deformed $AdS_5\times S^5$ background with one spin along AdS$_5$ and two angular momenta along $S^5$. We find the spiky string solutions and present the dispersion relation among various charges in this background. We further generalize the result to the case of four angular momenta along $AdS_5 \times S_γ^5$.

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