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"Koch, Robert"
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Untraceable
Jennifer Marsh is an FBI secret service agent who gets caught up in a very personal and deadly cat-and-mouse game with a serial killer. The killer knows that people are drawn to the curious and the dark side of things. They will log onto an 'untraceable' website where the killer conducts violent and painful murders live on the internet. The more people who log on and enter the website, the quicker and more violently the victim dies.
DVD
Holography of information in AdS/CFT
A
bstract
The principle of the holography of information states that in a theory of quantum gravity a copy of all the information available on a Cauchy slice is also available near the boundary of the Cauchy slice. This redundancy in the theory is already present at low energy. In the context of the AdS/CFT correspondence, this principle can be translated into a statement about the dual conformal field theory. We carry out this translation and demonstrate that the principle of the holography of information holds in bilocal holography.
Journal Article
Complexity from spinning primaries
A
bstract
We define circuits given by unitary representations of Lorentzian conformal field theory in 3 and 4 dimensions. Our circuits start from a spinning primary state, allowing us to generalize formulas for the circuit complexity obtained from circuits starting from scalar primary states. These results are nicely reproduced in terms of the geometry of coadjoint orbits of the conformal group. In contrast to the complexity geometry obtained from scalar primary states, the geometry is more complicated and the existence of conjugate points, signaling the saturation of complexity, remains open.
Journal Article
Gauge invariants, correlators and holography in bosonic and fermionic tensor models
A
bstract
Motivated by the close connection of tensor models to the SYK model, we use representation theory to construct the complete set of gauge invariant observables for bosonic and fermionic tensor models. Correlation functions of the gauge invariant operators in the free theory are computed exactly. The gauge invariant operators close a ring. The structure constants of the ring are described explicitly. Finally, we construct a collective field theory description of the bosonic tensor model.
Journal Article
AdS maps and diagrams of bi-local holography
A
bstract
We present in detail the basic ingredients contained in bi-local holography, representing a constructive scheme for reconstructing AdS bulk theories in Vectorial/AdS duality. Explicit Mapping to bulk AdS and higher spin fields is seen to be given by a double Fourier transform. All order interactions are explicitly specified through the collective action. This generates bulk Feynman (Witten) diagrams (at tree and loop level). We give details of the four-point case evaluation. It is noted that the bi-local construction goes beyond the assumptions in various discussions of non-locality.
Journal Article
Gravitational dynamics from collective field theory
A
bstract
We consider the relevance of a collective field theory description for the AdS/CFT correspondence. Collective field theory performs a systematic reorganization of the degrees of freedom of a (non-gravitational) field theory, replacing the original loop expansion parameter ℏ with 1/
N
. Collective fields are over complete signalling a redundancy inherent in the theory. We propose that this over completeness is the mechanism by which one arrives at a holographic description, to be identified with the gravity dual. We find evidence for this by studying the redundancy of the collective field theory, showing that degrees of freedom in the bulk can be expressed as a linear combination of degrees of freedom contained in an arbitrarily small neighbourhood of the boundary.
Journal Article
Topological rejection of noise by quantum skyrmions
An open challenge in the context of quantum information processing and communication is improving the robustness of quantum information to environmental contributions of noise, a severe hindrance in real-world scenarios. Here, we show that quantum skyrmions and their nonlocal topological observables remain resilient to noise even as typical entanglement witnesses and measures of the state decay. This allows us to introduce the notion of digitization of quantum information based on our discrete topological quantum observables, foregoing the need for robustness of entanglement. We compliment our experiments with a full theoretical treatment that unlocks the quantum mechanisms behind the topological behavior, explaining why the topology leads to robustness. Our approach holds exciting promise for intrinsic quantum information resilience through topology, highly applicable to real-world systems such as global quantum networks and noisy quantum computers.
Recent work reported a non-local quantum entangled state of photons with skyrmionic topology. Here the authors demonstrate theoretically and experimentally that topological properties of this system are resilient to noise, even as entanglement measures decay, and elucidate the mechanisms behind this robustness.
Journal Article
A double coset ansatz for integrability in AdS/CFT
A
bstract
We give a proof that the expected counting of strings attached to giant graviton branes in
AdS
5
×
S
5
, as constrained by the Gauss Law, matches the dimension spanned by the expected dual operators in the gauge theory. The counting of string-brane configurations is formulated as a graph counting problem, which can be expressed as the number of points on a double coset involving permutation groups. Fourier transformation on the double coset suggests an ansatz for the diagonalization of the one-loop dilatation operator in this sector of strings attached to giant graviton branes. The ansatz agrees with and extends recent results which have found the dynamics of open string excitations of giants to be given by harmonic oscillators. We prove that it provides the conjectured diagonalization leading to harmonic oscillators.
Journal Article
Microscopic entanglement wedges
A
bstract
We study the holographic duality between the free O(
N
) vector model and higher spin gravity. Conserved spinning primary currents of the conformal field theory (CFT) are dual to spinning gauge fields in the gravity. Reducing to independent components of the conserved CFT currents one finds two components at each spin. After gauge fixing the gravity and then reducing to independent components, one finds two components of the gauge field at each spin. Collective field theory provides a systematic way to map between these two sets of degrees of freedom, providing a complete and explicit identification between the dynamical degrees of freedom of the CFT and the dual gravity. The resulting map exhibits many features expected of holographic duality: it provides a valid bulk reconstruction, it reproduces insights expected from the holography of information and it provides a microscopic derivation of entanglement wedge reconstruction.
Journal Article
Large N optimization for multi-matrix systems
A
bstract
In this work we revisit the problem of solving multi-matrix systems through numerical large
N
methods. The framework is a collective, loop space representation which provides a constrained optimization problem, addressed through master-field minimization. This scheme applies both to multi-matrix integrals (
c
= 0 systems) and multi-matrix quantum mechanics (
c
= 1 systems). The complete fluctuation spectrum is also computable in the above scheme, and is of immediate physical relevance in the later case. The complexity (and the growth of degrees of freedom) at large
N
have stymied earlier attempts and in the present work we present significant improvements in this regard. The (constrained) minimization and spectrum calculations are easily achieved with close to 10
4
variables, giving solution to Migdal-Makeenko, and collective field equations. Considering the large number of dynamical (loop) variables and the extreme nonlinearity of the problem, high precision is obtained when confronted with solvable cases. Through numerical results presented, we prove that our scheme solves, by numerical loop space methods, the general two matrix model problem.
Journal Article