The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
Ismail Zahed - One of the best experts on this subject based on the ideXlab platform.
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Stretched String with self-interaction at the Hagedorn point: Spatial sizes and black holes
Physical Review D, 2015Co-Authors: Yachao Qian, Ismail ZahedAbstract:We analyze the length, mass and spatial distribution of a discretized transverse String in ${D}_{\ensuremath{\perp}}$ dimensions with fixed end points near its Hagedorn temperature. We suggest that such a String may dominate the (holographic) Pomeron kinematics for dipole-dipole scattering at intermediate and small impact parameters. Attractive self-String interactions cause the transverse String size to contract away from its diffusive size, a mechanism reminiscent of the String-black hole transmutation. The String shows sizable asymmetries in the transverse plane that translate to primordial azimuthal asymmetries in the Stringy particle production in the Pomeron kinematics for current pp and pA collisions at collider energies.
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Stretched String with Self-Interaction at High Resolution: Spatial Sizes and Saturation
Physical Review D, 2015Co-Authors: Yachao Qian, Ismail ZahedAbstract:We model the (holographic) QCD Pomeron as a long and Stretched (fixed impact parameter) transverse quantum String in flat ${D}_{\ensuremath{\perp}}=3$ dimensions. After discretizing the String in $N$ String bits, we analyze its length, mass and spatial distribution for large $N$ or low $x$ ($x=1/N$), and away from its Hagedorn point. The String bit distribution shows sizable asymmetries in the transverse plane that may translate to azimuthal asymmetries in primordial particle production in the Pomeron kinematics, and the flow moments in minimum bias $pp$ and $pA$ events. At moderately low $x$ and relatively small String self-interactions ${g}_{s}\ensuremath{\approx}{\ensuremath{\alpha}}_{s}$ (the gauge coupling), a presaturation phase is identified whereby the String transverse area undergoes a sharp transition from a large diffusive growth to a small fixed size area set by few String lengths ${l}_{s}$. For lower values of $x$ the transverse String bit density is shown to increase as $1/x$ before saturating at the Bekenstein bound of one bit per Planck area with the Planck length ${l}_{P}/{l}_{s}\ensuremath{\approx}{\ensuremath{\alpha}}_{s}^{2/3}$. We argue that the effects of the ${\mathrm{AdS}}_{5}$ curvature on the interacting String may be estimated using an effective transverse dimension between the interacting String bits. The result is a smoother transition with a transverse String bit density increasing as $1/{x}^{0.31}$.
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Stretched String with Self-Interaction at High Resolution: Spatial Sizes and Saturation
arXiv: High Energy Physics - Phenomenology, 2014Co-Authors: Yachao Qian, Ismail ZahedAbstract:We model the (holographic) QCD Pomeron as a long and Stretched (fixed impact parameter) transverse quantum String in flat $D_\perp=3$ dimensions. After discretizing the String in $N$ String bits, we analyze its length, mass and spatial distribution for large $N$ or low-x ($x=1/N$), and away from its Hagedorn point. The String bit distribution shows sizable asymmetries in the transverse plane that may translate to azimuthal asymmetries in primordial particle production in the Pomeron kinematics, and the flow moments in minimum bias $pp$ and $pA$ events. At moderately low-x and relatively small String self-interactions $g_s\approx \alpha_s$ (the gauge coupling), a pre-saturation phase is identified whereby the String transverse area undergoes a sharp transition from a large diffusive growth to a small fixed size area set by few String lengths $l_s$. For lower values of $x$ the transverse String bit density is shown to increase as $1/x$ before saturating at the Bekenstein bound of one bit per Planck area with the Planck length $l_P/l_s\approx \alpha_s^{2/3}$. We argue that the effects of the AdS$_5$ curvature on the interacting String maybe estimated using an effective transverse dimension between the interacting String bits. The result is a smoother transition with a transverse String bit density increasing as $1/x^{0.31}$.
Hwa-yaw Tam - One of the best experts on this subject based on the ideXlab platform.
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Maximum amplification of a String transverse-force amplifier in fiber Bragg grating accelerometers
OSA Continuum, 2019Co-Authors: Tommy H.t. Chan, Man Hong Yau, David Thambiratnam, Hwa-yaw TamAbstract:Fiber Bragg grating (FBG) accelerometers using transverse forces are very sensitive. When a transverse force is applied to a lightly Stretched String fixed by its two ends, a much stronger axial force along the String will be induced. So, the transverse force is amplified and converted into the axial force. At a given pre-strain of the String, the maximum amplification and requirements to obtain it have not been clearly demonstrated. Here, we theoretically prove and experimentally verify that the maximum amplification occurs when the strain induced by the transverse force approximately equals the pre-strain. This revelation improves the understanding of FBG accelerometers using transverse forces.
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Fiber Bragg grating strain modulation based on nonlinear String transverse-force amplifier.
Optics letters, 2013Co-Authors: Kuo Li, Man Hong Yau, David Thambiratnam, Tommy H.t. Chan, Hwa-yaw TamAbstract:The only effective method of fiber Bragg grating (FBG) strain modulation has been by changing the distance between its two fixed ends. We demonstrate an alternative that is more sensitive to force based on the nonlinear amplification relationship between a transverse force applied to a Stretched String and its induced axial force. It may improve the sensitivity and size of an FBG force sensor, reduce the number of FBGs needed for multiaxial force monitoring, and control the resonant frequency of an FBG accelerometer.
Yachao Qian - One of the best experts on this subject based on the ideXlab platform.
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Stretched String with self-interaction at the Hagedorn point: Spatial sizes and black holes
Physical Review D, 2015Co-Authors: Yachao Qian, Ismail ZahedAbstract:We analyze the length, mass and spatial distribution of a discretized transverse String in ${D}_{\ensuremath{\perp}}$ dimensions with fixed end points near its Hagedorn temperature. We suggest that such a String may dominate the (holographic) Pomeron kinematics for dipole-dipole scattering at intermediate and small impact parameters. Attractive self-String interactions cause the transverse String size to contract away from its diffusive size, a mechanism reminiscent of the String-black hole transmutation. The String shows sizable asymmetries in the transverse plane that translate to primordial azimuthal asymmetries in the Stringy particle production in the Pomeron kinematics for current pp and pA collisions at collider energies.
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Stretched String with Self-Interaction at High Resolution: Spatial Sizes and Saturation
Physical Review D, 2015Co-Authors: Yachao Qian, Ismail ZahedAbstract:We model the (holographic) QCD Pomeron as a long and Stretched (fixed impact parameter) transverse quantum String in flat ${D}_{\ensuremath{\perp}}=3$ dimensions. After discretizing the String in $N$ String bits, we analyze its length, mass and spatial distribution for large $N$ or low $x$ ($x=1/N$), and away from its Hagedorn point. The String bit distribution shows sizable asymmetries in the transverse plane that may translate to azimuthal asymmetries in primordial particle production in the Pomeron kinematics, and the flow moments in minimum bias $pp$ and $pA$ events. At moderately low $x$ and relatively small String self-interactions ${g}_{s}\ensuremath{\approx}{\ensuremath{\alpha}}_{s}$ (the gauge coupling), a presaturation phase is identified whereby the String transverse area undergoes a sharp transition from a large diffusive growth to a small fixed size area set by few String lengths ${l}_{s}$. For lower values of $x$ the transverse String bit density is shown to increase as $1/x$ before saturating at the Bekenstein bound of one bit per Planck area with the Planck length ${l}_{P}/{l}_{s}\ensuremath{\approx}{\ensuremath{\alpha}}_{s}^{2/3}$. We argue that the effects of the ${\mathrm{AdS}}_{5}$ curvature on the interacting String may be estimated using an effective transverse dimension between the interacting String bits. The result is a smoother transition with a transverse String bit density increasing as $1/{x}^{0.31}$.
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Stretched String with Self-Interaction at High Resolution: Spatial Sizes and Saturation
arXiv: High Energy Physics - Phenomenology, 2014Co-Authors: Yachao Qian, Ismail ZahedAbstract:We model the (holographic) QCD Pomeron as a long and Stretched (fixed impact parameter) transverse quantum String in flat $D_\perp=3$ dimensions. After discretizing the String in $N$ String bits, we analyze its length, mass and spatial distribution for large $N$ or low-x ($x=1/N$), and away from its Hagedorn point. The String bit distribution shows sizable asymmetries in the transverse plane that may translate to azimuthal asymmetries in primordial particle production in the Pomeron kinematics, and the flow moments in minimum bias $pp$ and $pA$ events. At moderately low-x and relatively small String self-interactions $g_s\approx \alpha_s$ (the gauge coupling), a pre-saturation phase is identified whereby the String transverse area undergoes a sharp transition from a large diffusive growth to a small fixed size area set by few String lengths $l_s$. For lower values of $x$ the transverse String bit density is shown to increase as $1/x$ before saturating at the Bekenstein bound of one bit per Planck area with the Planck length $l_P/l_s\approx \alpha_s^{2/3}$. We argue that the effects of the AdS$_5$ curvature on the interacting String maybe estimated using an effective transverse dimension between the interacting String bits. The result is a smoother transition with a transverse String bit density increasing as $1/x^{0.31}$.
Stefan Hutzler - One of the best experts on this subject based on the ideXlab platform.
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Onset of rigidity for Stretched String networks
EPL, 2005Co-Authors: Gareth Delaney, Denis Weaire, Stefan HutzlerAbstract:We define and analyse an elementary model for a network of Strings with random natural lengths. As this system is expanded, a threshold is reached where some of the Strings form a taut String network. Further expansion increases the fraction of taut Strings, until eventually all Strings are taut and the classical problem of a spring network is recovered. Here we provide an analysis of the properties of the system at and beyond the threshold expansion, relating results to the expectations of constraint theory.
B. Roberts - One of the best experts on this subject based on the ideXlab platform.
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The modes of oscillation of a prominence. III. The slab in a skewed magnetic field.
Astronomy and Astrophysics, 1993Co-Authors: P. S. Joarder, B. RobertsAbstract:We consider theoretically the possible modes of oscillation of a solar quiescent prominence, treating the prominence as a plasma slab embedded in a uniform, line-tied magnetic field that is inclined at a small angle (≃ 20°) to the long axis of the slab. Particularly interesting is the appearance of a String Alfven mode that is analogous to the fundamental mode of vibration of a Stretched String loaded with a heavy mass at its centre. This mode, along with a slow internal mode of the slab, may correspond to the observed long period (40-90 min) oscillation of quiescent prominences. Intermediate periodicities, in the range 8-20 min, may be associated with an internal Alfven mode and a fast String mode
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The modes of oscillation of a prominence. II : The slab with transverse magnetic field
Astronomy and Astrophysics, 1992Co-Authors: P. S. Joarder, B. RobertsAbstract:The possible magnetoacoustic modes of oscillation in a prominence that may arise solely due to a weak transverse magnetic field component are investigated theoretically. The prominence is modelled as an infinitely long plasma slab embedded in a uniform magnetic field that threads the prominence transversely and is anchored to rigid walls on either side of the prominence. The effect of gravity is ignored. Particularly interesting in this study is the appearance of magnetosonic modes that are analogous to the fundamental mode of vibration of a Stretched String loaded with a heavy point mass at its centre
