The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Fraser Watson - One of the best experts on this subject based on the ideXlab platform.
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a new solar signal average maximum sunspot magnetic Fields independent of activity cycle
arXiv: Solar and Stellar Astrophysics, 2016Co-Authors: William Livingston, Fraser WatsonAbstract:Over the past five years, 2010-2015, we have observed, in the near infrared (IR), the maximum magnetic Field strengths for 4145 sunspot umbrae. Herein we distinguish Field strengths from Field Flux. (Most solar magnetographs measure Flux). Maximum Field strength in umbrae is co-spatial with the position of umbral minimum brightness (Norton and Gilman, 2004). We measure Field strength by the Zeeman splitting of the Fe 15648.5 A spectral line. We show that in the IR no cycle dependence on average maximum Field strength (2050 G) has been found +/- 20 Gauss. A similar analysis of 17,450 spots observed by the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory reveal the same cycle independence +/- 0.18 G., or a variance of 0.01%. This is found not to change over the ongoing 2010-2015 minimum to maximum cycle. Conclude the average maximum umbral Fields on the Sun are constant with time.
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a new solar signal average maximum sunspot magnetic Fields independent of activity cycle
Geophysical Research Letters, 2015Co-Authors: William Livingston, Fraser WatsonAbstract:Over the past 5 years, 2010 to April 2015, we observed 4176 sunspot umbrae in the infrared (IR) to measure maximum magnetic Field strengths from the Zeeman splitting of Fe 15,648.5 A. Herein we distinguish “Field strengths” from “Field Flux.” Field strengths range from 1500 G in pores to 3500+ in large spots. We made one observation per spot per observing day, ignoring spot size. We show that in the IR no activity cycle dependence on average maximum Field strength (2070 ± 20 G) has been found. A similar analysis of 17,450 spots observed in space by the Helioseismic and Magnetic Imager reveals a similar cycle independence (2050 ± 0.18 G). We conclude that the average maximum umbral Fields are constant with time and independent of the activity cycle within our time coverage.
Donovan Young - One of the best experts on this subject based on the ideXlab platform.
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chiral primary one point functions in the d3 d7 defect conformal Field theory
Journal of High Energy Physics, 2013Co-Authors: Charlotte Kristjansen, Gordon W Semenoff, Donovan YoungAbstract:We compute the one-point functions of chiral primary operators in the nonsupersymmetric defect conformal Field theory that is dual to the IIB string theory on AdS5 S 5 background with a probe D7 brane with internal gauge Field Flux, both in perturbative Yang-Mills theory and in the string theory dual. The former is expected to be accurate at weak coupling whereas the latter should be accurate in the planar strong coupling limit of the gauge theory. We consider the distinct cases where the D7 brane has geometry AdS4 S 4 with an instanton bundle of the worldvolume gauge Fields on S 4 and AdS4 S 2 S 2 with Dirac monopole bundles on each S 2 . The gauge theory computation and the string theory computation can be compared directly in the planar limit and then a subsequent limit where the worldvolume Flux is large. We find that there is exact agreement between the two in the leading order.
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chiral primary one point functions in the d3 d7 defect conformal Field theory
arXiv: High Energy Physics - Theory, 2012Co-Authors: Charlotte Kristjansen, Gordon W Semenoff, Donovan YoungAbstract:We compute the one-point functions of chiral primary operators in the non-supersymmetric defect conformal Field theory that is dual to the IIB string theory on $AdS_5\times S^5$ background with a probe D7 brane with internal gauge Field Flux, both in perturbative Yang-Mills theory and in the string theory dual. The former is expected to be accurate at weak coupling whereas the latter should be accurate in the planar strong coupling limit of the gauge theory. We consider the distinct cases where the D7 brane has geometry $AdS_4\times S^4$ with an instanton bundle of the worldvolume gauge Fields on $S^4$ and $AdS_4\times S^2\times S^2$ with Dirac monopole bundles on each $S^2$. The gauge theory computation and the string theory computation can be compared directly in the planar limit and then a subsequent limit where the worldvolume Flux is large. We find that there is exact agreement between the two in the leading order.
Gordon W Semenoff - One of the best experts on this subject based on the ideXlab platform.
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chiral primary one point functions in the d3 d7 defect conformal Field theory
Journal of High Energy Physics, 2013Co-Authors: Charlotte Kristjansen, Gordon W Semenoff, Donovan YoungAbstract:We compute the one-point functions of chiral primary operators in the nonsupersymmetric defect conformal Field theory that is dual to the IIB string theory on AdS5 S 5 background with a probe D7 brane with internal gauge Field Flux, both in perturbative Yang-Mills theory and in the string theory dual. The former is expected to be accurate at weak coupling whereas the latter should be accurate in the planar strong coupling limit of the gauge theory. We consider the distinct cases where the D7 brane has geometry AdS4 S 4 with an instanton bundle of the worldvolume gauge Fields on S 4 and AdS4 S 2 S 2 with Dirac monopole bundles on each S 2 . The gauge theory computation and the string theory computation can be compared directly in the planar limit and then a subsequent limit where the worldvolume Flux is large. We find that there is exact agreement between the two in the leading order.
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chiral primary one point functions in the d3 d7 defect conformal Field theory
arXiv: High Energy Physics - Theory, 2012Co-Authors: Charlotte Kristjansen, Gordon W Semenoff, Donovan YoungAbstract:We compute the one-point functions of chiral primary operators in the non-supersymmetric defect conformal Field theory that is dual to the IIB string theory on $AdS_5\times S^5$ background with a probe D7 brane with internal gauge Field Flux, both in perturbative Yang-Mills theory and in the string theory dual. The former is expected to be accurate at weak coupling whereas the latter should be accurate in the planar strong coupling limit of the gauge theory. We consider the distinct cases where the D7 brane has geometry $AdS_4\times S^4$ with an instanton bundle of the worldvolume gauge Fields on $S^4$ and $AdS_4\times S^2\times S^2$ with Dirac monopole bundles on each $S^2$. The gauge theory computation and the string theory computation can be compared directly in the planar limit and then a subsequent limit where the worldvolume Flux is large. We find that there is exact agreement between the two in the leading order.
R C Rashkov - One of the best experts on this subject based on the ideXlab platform.
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critical point in a holographic defect Field theory
Journal of High Energy Physics, 2019Co-Authors: Veselin G Filev, R C RashkovAbstract:We study a holographic gauge theory dual to the D3/D5 intersection. We consider a pure gauge B-Field Flux through the internal two-sphere wrapped by the probe D5-brane, which corresponds to a non-commutative configuration of adjoint scalars. There is a domain wall separating the theory into regions with different ranks of the adjoint group. At zero temperature the theory is supersymmetric and at finite temperature there is a critical point of a second order phase transition. We study the corresponding critical exponents and find that the second derivatives of the free energy, with respect to the bare mass and the magnetic Field, diverge with a critical exponent of −2/3.
William Livingston - One of the best experts on this subject based on the ideXlab platform.
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a new solar signal average maximum sunspot magnetic Fields independent of activity cycle
arXiv: Solar and Stellar Astrophysics, 2016Co-Authors: William Livingston, Fraser WatsonAbstract:Over the past five years, 2010-2015, we have observed, in the near infrared (IR), the maximum magnetic Field strengths for 4145 sunspot umbrae. Herein we distinguish Field strengths from Field Flux. (Most solar magnetographs measure Flux). Maximum Field strength in umbrae is co-spatial with the position of umbral minimum brightness (Norton and Gilman, 2004). We measure Field strength by the Zeeman splitting of the Fe 15648.5 A spectral line. We show that in the IR no cycle dependence on average maximum Field strength (2050 G) has been found +/- 20 Gauss. A similar analysis of 17,450 spots observed by the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory reveal the same cycle independence +/- 0.18 G., or a variance of 0.01%. This is found not to change over the ongoing 2010-2015 minimum to maximum cycle. Conclude the average maximum umbral Fields on the Sun are constant with time.
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a new solar signal average maximum sunspot magnetic Fields independent of activity cycle
Geophysical Research Letters, 2015Co-Authors: William Livingston, Fraser WatsonAbstract:Over the past 5 years, 2010 to April 2015, we observed 4176 sunspot umbrae in the infrared (IR) to measure maximum magnetic Field strengths from the Zeeman splitting of Fe 15,648.5 A. Herein we distinguish “Field strengths” from “Field Flux.” Field strengths range from 1500 G in pores to 3500+ in large spots. We made one observation per spot per observing day, ignoring spot size. We show that in the IR no activity cycle dependence on average maximum Field strength (2070 ± 20 G) has been found. A similar analysis of 17,450 spots observed in space by the Helioseismic and Magnetic Imager reveals a similar cycle independence (2050 ± 0.18 G). We conclude that the average maximum umbral Fields are constant with time and independent of the activity cycle within our time coverage.