다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

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The Observation of Gravitational Waves from a Binary Black Hole Merger

Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics

A black hole may carry ``soft hair,'' low-energy quantum excitations that release information when the black hole evaporates.

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Soft Hair on Black Holes

This is a redacted transcript of a course given by the author at Harvard in spring semester 2016. It contains a pedagogical overview of recent developments connecting the subjects of soft theorems, the memory effect and asymptotic symmetries in four-dimensional QED, nonabelian gauge theory and gravity with applications to black holes. The lectures may be viewed online at this https URL. Please send typos or corrections to strominger@physics.this http URL.

Lectures on the Infrared Structure of Gravity and Gauge Theory

We consider a holographic model consisting of Einstein-Maxwell theory in d + 1 bulk spacetime dimensions with d 1 massless scalarelds. Momentum relaxation is realised simply through spatially dependent sources for operators dual to the neutral scalars, which can be engineered so that the bulk stress tensor and resulting black brane geometry are homogeneous and isotropic. We analytically calculate the DC conductivity, which isnite. In the d = 3 case, both the black hole geometry and shear-mode current- current correlators are those of a sector of massive gravity.

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A simple holographic model of momentum relaxation

We consider the spontaneous breaking of translational symmetry and identify the associated Goldstone mode — a longitudinal phonon — in a holographic model with Bianchi VII helical symmetry For the first time in holography, we observe the pinning of this mode after introducing a source for explicit breaking compatible with the helical symmetry of our setup We study the dispersion relation of the resulting pseudo-Goldstone mode, uncovering how its speed and mass gap depend on the amplitude of the source and temperature In addition, we extract the optical conductivity as a function of frequency, which reveals a metal-insulator transition as a consequence of the pinning

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Pinning of longitudinal phonons in holographic spontaneous helices

Scalars in AdS
 d+1 with squared masses in the Breitenlohner-Freedman window $$ - {d^{{2}}}/{4} \leqslant {m^{{2}}} < - {d^{{2}}}/{4} + {1} $$
 (in units with the AdS scale l set to 1) are known to enjoy a variety of boundary conditions. For larger masses $$ {m^{{2}}} > - {d^{{2}}}/{4} + {1} $$
 , unitarity bounds in possible dual CFTs suggest that such general boundary conditions should lead to ghosts. We show that this is not always the case as, for conformally-invariant boundary conditions in Poincare AdS that would naively violate unitarity bounds, the system is generically ghost-free. Conflicts with unitarity bounds are avoided due to the presence of unexpected pure gauge modes and an associated infrared divergence. The expected ghosts appear when the IR divergence is removed either by deforming these boundary conditions or considering global AdS.

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AdS/CFT beyond the unitarity bound

Mott insulators form because of strong electron repulsions, being at the heart of strongly correlated electron physics. Conventionally these are understood as classical "traffic jams" of electrons described by a short-ranged entangled product ground state. Exploiting the holographic duality, which maps the physics of densely entangled matter onto gravitational black hole physics, we show how Mott-insulators can be constructed departing from entangled non-Fermi liquid metallic states, such as the strange metals found in cuprate superconductors. These "entangled Mott insulators" have traits in common with the "classical" Mott insulators, such as the formation of Mott gap in the optical conductivity, super-exchange-like interactions, and form "stripes" when doped. They also exhibit new properties: the ordering wave vectors are detached from the number of electrons in the unit cell, and the DC resistivity diverges algebraically instead of exponentially as function of temperature. These results may shed light on the mysterious ordering phenomena observed in underdoped cuprates.

Doping the holographic Mott insulator

Mott insulators form because of strong electron repulsions and are at the heart of strongly correlated electron physics. Conventionally these are understood as classical ‘traffic jams’ of electrons described by a short-ranged entangled product ground state. Exploiting the holographic duality, which maps the physics of densely entangled matter onto gravitational black hole physics, we show how Mott-like insulators can be constructed departing from entangled non-Fermi liquid metallic states, such as the strange metals found in cuprate superconductors. These ‘entangled Mott insulators’ have traits in common with the ‘classical’ Mott insulators, such as the formation of a Mott gap in the optical conductivity, super-exchange-like interactions and the formation of ‘stripes’ upon doping. They also exhibit new properties: the ordering wavevectors are detached from the number of electrons in the unit cell, and the d.c. resistivity diverges algebraically instead of exponentially as a function of temperature. These results may shed light on the mysterious ordering phenomena observed in underdoped cuprates. A generalized Mott-insulating state is found theoretically starting from a holographic model. The state has features in common with the conventional variety, and upon doping shares striking similarities with the stripe phases found in cuprates.

Tomas Andrade

Papers

A simple holographic model of momentum relaxation

Pinning of longitudinal phonons in holographic spontaneous helices

AdS/CFT beyond the unitarity bound

Doping the holographic Mott insulator

Doping the holographic Mott insulator