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Kristan Jensen

Bio: Kristan Jensen is an academic researcher from San Francisco State University. The author has contributed to research in topics: AdS/CFT correspondence & Gauge theory. The author has an hindex of 44, co-authored 84 publications receiving 5856 citations. Previous affiliations of Kristan Jensen include C. N. Yang Institute for Theoretical Physics & University of Victoria.


Papers
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TL;DR: A generic theory of gravity near a two-dimensional anti-de Sitter spacetime throat is rewritten as a novel hydrodynamics coupled to the correlation functions of a conformal quantum mechanics to find that the dual is maximally chaotic.
Abstract: We revisit two-dimensional holography with the Sachdev-Ye-Kitaev models in mind. Our main result is to rewrite a generic theory of gravity near a two-dimensional anti-de Sitter spacetime throat as a novel hydrodynamics coupled to the correlation functions of a conformal quantum mechanics. This gives a prescription for the computation of n-point functions in the dual quantum mechanics. We thereby find that the dual is maximally chaotic.

722 citations

Journal ArticleDOI
TL;DR: In this article, the thermodynamic properties of the Sachdev-Ye-Kitaev (SYK) models of fermions with a conserved fermion number Q were investigated.
Abstract: We compute the thermodynamic properties of the Sachdev-Ye-Kitaev (SYK) models of fermions with a conserved fermion number Q. We extend a previously proposed Schwarzian effective action to include a phase field, and this describes the low-temperature energy and Q fluctuations. We obtain higher-dimensional generalizations of the SYK models which display disordered metallic states without quasiparticle excitations, and we deduce their thermoelectric transport coefficients. We also examine the corresponding properties of Einstein-Maxwell-axion theories on black brane geometries which interpolate from either AdS4 or AdS5 to an AdS2×R2 or AdS2×R3 near-horizon geometry. These provide holographic descriptions of nonquasiparticle metallic states without momentum conservation. We find a precise match between low-temperature transport and thermodynamics of the SYK and holographic models. In both models, the Seebeck transport coefficient is exactly equal to the Q derivative of the entropy. For the SYK models, quantum chaos, as characterized by the butterfly velocity and the Lyapunov rate, universally determines the thermal diffusivity, but not the charge diffusivity.

453 citations

Journal ArticleDOI
TL;DR: A generating functional is presented which describes the equilibrium thermodynamic response of a relativistic system to external sources and provides a technique for efficiently computing n-point zero-frequency correlation functions within the hydrodynamic derivative expansion without the need to explicitly solve the equations of hydrodynamics.
Abstract: We present a generating functional which describes the equilibrium thermodynamic response of a relativistic system to external sources. A variational principle gives rise to constraints on the response parameters of relativistic hydrodynamics without making use of an entropy current. Our method reproduces and extends results available in the literature. It also provides a technique for efficiently computing $n$-point zero-frequency correlation functions within the hydrodynamic derivative expansion without the need to explicitly solve the equations of hydrodynamics.

333 citations

Journal ArticleDOI
TL;DR: In this paper, the authors argue that pure and mixed gravitational anomalies generate a "Casimir momentum" which manifests itself as parity violating coefficients in the hydrodynamic stress tensor and charge current.
Abstract: By studying the Euclidean partition function on a cone, we argue that pure and mixed gravitational anomalies generate a “Casimir momentum” which manifests itself as parity violating coefficients in the hydrodynamic stress tensor and charge current. The coefficients generated by these anomalies enter at a lower order in the hydrodynamic gradient expansion than would be naively expected. In 1 + 1 dimensions, the gravitational anomaly affects coefficients at zeroth order in the gradient expansion. The mixed anomaly in 3 + 1 dimensions controls the value of coefficients at first order in the gradient expansion.

222 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compute the penetration depth of a light quark moving through a large supersymmetric Yang-Mills plasma using gauge/gravity duality and a combination of analytic and numerical techniques.
Abstract: We compute the penetration depth of a light quark moving through a large ${N}_{\mathrm{c}}$, strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills plasma using gauge/gravity duality and a combination of analytic and numerical techniques. We find that the maximum distance a quark with energy $E$ can travel through a plasma is given by $\ensuremath{\Delta}{x}_{\mathrm{max} }(E)=(\mathcal{C}/T)(E/T\sqrt{\ensuremath{\lambda}}{)}^{1/3}$ with $\mathcal{C}\ensuremath{\approx}0.5$.

183 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
01 Dec 1949-Nature
TL;DR: Wentzel and Jauch as discussed by the authors described the symmetrization of the energy momentum tensor according to the Belinfante Quantum Theory of Fields (BQF).
Abstract: To say that this is the best book on the quantum theory of fields is no praise, since to my knowledge it is the only book on this subject But it is a very good and most useful book The original was written in German and appeared in 1942 This is a translation with some minor changes A few remarks have been added, concerning meson theory and nuclear forces, also footnotes referring to modern work in this field, and finally an appendix on the symmetrization of the energy momentum tensor according to Belinfante Quantum Theory of Fields Prof Gregor Wentzel Translated from the German by Charlotte Houtermans and J M Jauch Pp ix + 224, (New York and London: Interscience Publishers, Inc, 1949) 36s

2,935 citations

01 Jan 2011

2,117 citations

Book
01 Jan 1957

1,574 citations

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional dilaton gravity system was studied and the symmetry breaking was studied in terms of a Schwarzian derivative effective action for a reparametrization.
Abstract: We study a two dimensional dilaton gravity system, recently examined by Almheiri and Polchinski, which describes near extremal black holes, or more generally, nearly $AdS_2$ spacetimes. The asymptotic symmetries of $AdS_2$ are all the time reparametrizations of the boundary. These symmetries are spontaneously broken by the $AdS_2$ geometry and they are explicitly broken by the small deformation away from $AdS_2$. This pattern of spontaneous plus explicit symmetry breaking governs the gravitational backreaction of the system. It determines several gravitational properties such as the linear in temperature dependence of the near extremal entropy as well as the gravitational corrections to correlation functions. These corrections include the ones determining the growth of out of time order correlators that is indicative of chaos. These gravitational aspects can be described in terms of a Schwarzian derivative effective action for a reparametrization.

1,214 citations