Bulletin of the American Physical Society
APS March Meeting 2016
Volume 61, Number 2
Monday–Friday, March 14–18, 2016; Baltimore, Maryland
Session F44: Gravity and Quantum InformationFocus
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Sponsoring Units: GQI Chair: Caslav Brukner, IQOQI, Austrian Academy of Sciences; Faculty of Physics, University of Vienna Room: 347 |
Tuesday, March 15, 2016 11:15AM - 11:51AM |
F44.00001: Constraining Dark Energy in Table-Top Quantum Experiments Invited Speaker: Holger Mueller If dark energy is a light scalar field, it might interact with normal matter. The interactions, however, are suppressed in the leading models, which are thus compatible with current cosmological observations as well as solar-system and laboratory studies. Such suppression typically relies on the scalar's interaction with macroscopic amounts of ordinary matter but can be bypassed by studying the interaction with individual particles.\footnote{C. Burrage, E. J. Copeland, E. A. Hinds, Probing dark energy with atom interferometry. J. Cosmol. Astropart. Phys. {\bf 2015,} 042 (2015).} Using an atom interferometer, we have placed tight constraints on so-called chameleon models, ruling out interaction parameters smaller than $2.3\times 10^{-5}$, while $M \sim 1$ or larger would lead to conflict with macroscopic experiments.\footnote{P. Hamilton, M. Jaffe, P. Haslinger, Q. Simmons, H. M\"uller, and J. Khoury, Atom-interferometry constraints on dark energy. Science {\bf 349,} 849 (2015).} In order to close this gap, we have already increased the sensitivity hundredfold and are expecting a new constraint soon. Purpose-built experiments in the lab or on the international space station will completely close the gap and rule out chameleons and other theories such as symmetrons or $f(R)$ gravity. [Preview Abstract] |
Tuesday, March 15, 2016 11:51AM - 12:27PM |
F44.00002: Gravity and Quantum Mechanics Invited Speaker: Miles Blencowe The emergence of the macroscopic classical world from the microscopic quantum world is commonly understood to be a consequence of the fact that any given quantum system is open, unavoidably interacting with unobserved environmental degrees of freedom that will cause initial quantum superposition states of the system to decohere, resulting in classical mixtures of either-or alternatives. A fundamental question concerns how large a macroscopic object can be placed in a manifest quantum state, such as a center of mass quantum superposition state, under conditions where the effects of the interacting environmental degrees of freedom are reduced (i.e. in ultrahigh vacuum and at ultralow temperatures). Recent experiments have in fact demonstrated manifest quantum behavior in nano-to-micron-scale mechanical systems. Gravity has been invoked in various ways as playing a possible fundamental role in enforcing classicality of matter systems beyond a certain scale. Adopting the viewpoint that the standard perturbative quantization of general relativity provides an effective description of quantum gravity that is valid at ordinary energies, we show that it is possible to describe quantitatively how gravity as an environment can induce the decoherence of matter superposition states. The justification for such an approach follows from the fact that we are considering laboratory scale systems, where the matter is localized to regions of small curvature. As with other low energy effects, such as the quantum gravity correction to the Newtonian potential between two ordinary masses, it should be possible to quantitatively evaluate gravitationally induced decoherence rates by employing standard perturbative quantum gravity as an effective field theory; whatever the final form the eventual correct quantum theory of gravity takes, it must converge in its predictions with the effective field theory description at low energies. [Preview Abstract] |
Tuesday, March 15, 2016 12:27PM - 12:39PM |
F44.00003: Bidirectional holographic codes and sub-AdS locality Zhao Yang, Patrick Hayden, Xiaoliang Qi Tensor networks implementing quantum error correcting codes have recently been used as toy models of the holographic duality which explicitly realize some of the more puzzling features of the AdS/CFT correspondence. These models reproduce the Ryu-Takayanagi entropy formula for boundary intervals, and allow bulk operators to be mapped to the boundary in a redundant fashion. These exactly solvable, explicit models have provided valuable insight but nonetheless suffer from many deficiencies, some of which we attempt to address in this talk. We propose a new class of tensor network models that subsume the earlier advances and, in addition, incorporate additional features of holographic duality, including: (1) a holographic interpretation of all boundary states, not just those in a "code" subspace, (2) a set of bulk states playing the role of "classical geometries" which reproduce the Ryu-Takayanagi formula for boundary intervals, (3) a bulk gauge symmetry analogous to diffeomorphism invariance in gravitational theories, (4) emergent bulk locality for sufficiently sparse excitations, and the ability to describe geometry at sub-AdS resolutions or even flat space. [Preview Abstract] |
Tuesday, March 15, 2016 12:39PM - 12:51PM |
F44.00004: An extension to Galilean relativity gives rise to quantum mechanics framework Simon Berkovich The presented scheme for quantum mechanics appeared from considering Cellular Automaton Universe in view of the hidden energy associated with the property of inertia [1]. Galilean relativity states that all inertial frames are equivalent. Our consideration reveals one seemingly small exception - the original frame of reference for the material formations of the Cellular Automaton infrastructure is not isotropic. This frame of reference has a distinctive direction as long as elementary particles of matter are generated by cellular automaton relocations As a result, Cellular Automaton Universe basically complying with the laws of macrophysics for bulk bodies, could exhibit peculiar characteristics for microphysics.. Why the states of microobjects are described by complex numbers is obscure. The observables are presented by real numbers through corresponding macro manipulations. In the inertial frame with unidirectional anisotropy isolated particles are characterized by two numbers; magnitude of their velocity and inclination angle to motion direction. So, these quantum states are mapped to a complex Hilbert space with zero vector representing bulk bodies. The effect of spin may be associated with the sign of the inclination angle trending separations for Stern-Gerlach output and Paul Principle. [1\textbraceright Simon Berkovich, Law of inertia and the primal energy in the cellular automaton universe , Journal of Energy Challenges and Mechanics, vol.2(2015), issue 2, pp. 62-67 [Preview Abstract] |
Tuesday, March 15, 2016 12:51PM - 1:03PM |
F44.00005: Asymptotically Limitless Quantum Energy Teleportation via Qudit Probes Guillaume Verdon-Akzam, Eduardo Martín-Martínez, Achim Kempf We propose a modified Quantum Energy Teleportation (QET) scheme that uses arbitrary-dimensional qudit probes and polynomially localized Hamiltonians. We find that with an appropriate scaling of parameters, the teleported energy scales with the teleportation distance more favourably than the nonlocal tails of the Hamiltonians. We show that by allowing the exchange of arbitrary amounts of information between agents and in a suitable limit, an arbitrarily large amount of energy can be teleported through a massless quantum field. [Preview Abstract] |
Tuesday, March 15, 2016 1:03PM - 1:15PM |
F44.00006: Relativistic Quantum Communication and the Structure of Spacetime Eduardo Martin-Martinez We study the transmission of information and correlations through quantum fields in cosmological backgrounds. With this aim, we make use of quantum information tools to quantify the classical and quantum correlations induced by a quantum massless scalar field in two particle detectors, one located in the early universe (Alice's) and the other located at a later time (Bob's). In particular, we focus on two phenomena: a) the consequences on the transmission of information of the violations of the strong Huygens principle for quantum fields, and b) the analysis of the field vacuum correlations via correlation harvesting from Alice to Bob. We will study a standard cosmological model first and then assess whether these results also hold if we use other than the general relativistic dynamics. As a particular example, we will study the transmission of information through the Big Bounce, that replaces the Big Bang, in the effective dynamics of Loop Quantum Cosmology. We show that much more information reaches us through timelike channels (not mediated by real photons) than it is carried by rays of light, which are usually regarded as the only carriers of information. [Preview Abstract] |
Tuesday, March 15, 2016 1:15PM - 1:27PM |
F44.00007: Einstein's Equivalence Principle and Universal Decoherence inMassive Composite Quantum Systems Belinda Pang, Yanbei Chen We demonstrate that in matter wave interferometry, the presence of a uniform gravitational field acting on massive particles with internal degrees of freedom will lead to dephasing and a loss of visibility in the interference pattern, as also shown by previous authors. However,unlike the previous authors,we argue that this is not a universal decoherence mechanism in the sense that any quantum information is lost, and furthermore,that the quantum interference is recoverable.This is a key distinction, becauseirreversible effects such as decoherence on a quantum system due to uniform gravity impliesa violation of Einstein's Equivalence Principle (EEP)in the quantum regime.We show that the dephasing result can be recovered by considering an accelerating observer measuring a freely propagating system, and can be simply understood in terms of the difference in the internal state dependent time of arrival of particles to the screen. One can contrive detection schemes that adjusts the path lengths of particles to compensate for this difference and recover the full visibility, while coupling to no additional degrees of freedom.Therefore, the dephasing is an observer dependent effect. EEP is not violated, and uniform gravity is not a mechanism for universal decoherence. [Preview Abstract] |
Tuesday, March 15, 2016 1:27PM - 1:39PM |
F44.00008: Complete Sets of Solutions in Quantum Mechanics and their Connection with Gravity Rafael Sierra In typical non-relativistic quantum mechanical theory, solutions which are not normalizable are thrown away on the basis of being non-physical. The author does not contend that these solutions exist or are physically reasonable, but, these solutions do introduce interesting physics that can serve to connect the force of gravity with the laws of thermodynamics in a shockingly intimate way. The author will discuss the necessary extensions to the formalism of Schrodinger in order to better deal with and make sense of these solutions. In particular, some time will be devoted to the notion of entropy in systems involving these solutions. For particles sufficiently spaced-out, the second law of thermodynamics will yield dynamics that resemble classical expectations for gravity. Ultimately, gravity will be presented as a force necessary for the preservation of the second law of thermodynamics. Gravity and statistical mechanics will become connected at the quantum domain, provided the quantum domain is enlarged to include wave functions that are generally considered unreasonable. [Preview Abstract] |
Tuesday, March 15, 2016 1:39PM - 1:51PM |
F44.00009: Geodesics and Acceleration in Influence Theory James Walsh, Kevin Knuth Influence theory is concerned with a foundational approach where it is assumed that particles influence one another in a discrete one-to-one fashion. This results in a partially ordered set of influence events, called the influence network, where particles are represented by totally ordered chains of events. Information physics considers physical laws to result from consistent quantification of physical phenomena. Knuth and Bahreyni (2014) demonstrated that the mathematics of spacetime emerges from consistent quantification of influence events by embedded coordinated observers. Knuth (2014) showed that in 1$+$1 dimensions observer-based predictions about a free (uninfluenced) particle result in the Dirac equation. Here, we show that when a particle in 1$+$1 dimensions is influenced, it is uniquely and consistently described in terms of relativistic acceleration for constant rate of influence and in general obeys equations of the form of the geodesic equations of general relativity. This suggests that Influence Theory can also account for forces (like gravity), which give rise to well-known relativistic effects such as time dilation. [Preview Abstract] |
Tuesday, March 15, 2016 1:51PM - 2:03PM |
F44.00010: Gravity and Quantum Theory Unified Gary Warren Historic arguments against Aether theories disappear if the Aether is a 4D compressible hyperfluid in which each particle is our observation of a hypervortex, formed in and comprised of hyperfluid. Such Aether resolves ``spooky action at a distance'' which allows unification of gravity and quantum theory. Light is transverse waves in free space (away from hypervortices) in the hyperfluid. Their detailed behavior is why we observe a curved 3D Lorentz universe -- a slice through the 4D hyperverse. Meanwhile, detailed hypervortex behavior, including faster-than-light longitudinal waves in and along hypervortices, explain quantum phenomena. A particular Lagrangian for such a hyperfluid regenerates Maxwell's equations, plus an equation for gravity, and an equation for electric charge. Couplings among these equations generate a discrete spectrum of hypervortex solutions that we observe as a spectrum of particles. Gravity results from gradients in the fluid density near vortices. Observed clock rates depend on fluid density, and vortex motion thus intertwining gravity, clock rates and quantum phenomena. Implied experiments will be discussed.\\ \\ See: www.hypervortex.com [Preview Abstract] |
Tuesday, March 15, 2016 2:03PM - 2:15PM |
F44.00011: Geometry and dynamics of emergent spacetime from entanglement spectrum Hiroaki Matsueda We examine geometry and dynamics of classical spacetime derived from entanglement spectrum for 1D lattice free fermions. The spacetime is a kind of canonical parameter space defined by the Fisher information metric. The spectrum has exponential family form like thermal probability. Then, the metric is given by the second derivative of the Hessian potential that can be identified with the entanglement entropy. We emphasize that the canonical parameters are nontrivial functions of partial system size by the truncation, filling fraction of fermions, and time. We find that the emergent geometry becomes anti-de Sitter spacetime with imaginary time, and a radial axis as well as spacetime coordinates appears spontaneously. We also find that the information of the UV limit of the original fermions lives in the boundary of the anti-de Sitter spacetime. These findings strongly suggest that the Hessian potential for free fermions has enough geometrical meaning associated with gauge-gravity correspondence. [Preview Abstract] |
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