6,350 research outputs found
Entanglement Conservation, ER=EPR, and a New Classical Area Theorem for Wormholes
We consider the question of entanglement conservation in the context of the
ER=EPR correspondence equating quantum entanglement with wormholes. In quantum
mechanics, the entanglement between a system and its complement is conserved
under unitary operations that act independently on each; ER=EPR suggests that
an analogous statement should hold for wormholes. We accordingly prove a new
area theorem in general relativity: for a collection of dynamical wormholes and
black holes in a spacetime satisfying the null curvature condition, the maximin
area for a subset of the horizons (giving the largest area attained by the
minimal cross section of the multi-wormhole throat separating the subset from
its complement) is invariant under classical time evolution along the outermost
apparent horizons. The evolution can be completely general, including horizon
mergers and the addition of classical matter satisfying the null energy
condition. This theorem is the gravitational dual of entanglement conservation
and thus constitutes an explicit characterization of the ER=EPR duality in the
classical limit.Comment: 16 pages, 2 figure
Splitting Spacetime and Cloning Qubits: Linking No-Go Theorems across the ER=EPR Duality
We analyze the no-cloning theorem in quantum mechanics through the lens of
the proposed ER=EPR (Einstein-Rosen = Einstein-Podolsky-Rosen) duality between
entanglement and wormholes. In particular, we find that the no-cloning theorem
is dual on the gravity side to the no-go theorem for topology change, violating
the axioms of which allows for wormhole stabilization and causality violation.
Such a duality between important no-go theorems elucidates the proposed
connection between spacetime geometry and quantum entanglement.Comment: 6 pages, 2 figure
Supermassive Black Holes from Ultra-Strongly Self-Interacting Dark Matter
We consider the cosmological consequences if a small fraction () of the dark matter is ultra-strongly self-interacting, with an elastic
self-interaction cross-section per unit mass .
This possibility evades all current constraints that assume that the
self-interacting component makes up the majority of the dark matter.
Nevertheless, even a small fraction of ultra-strongly self-interacting dark
matter (uSIDM) can have observable consequences on astrophysical scales. In
particular, the uSIDM subcomponent can undergo gravothermal collapse and form
seed black holes in the center of a halo. These seed black holes, which form
within several hundred halo interaction times, contain a few percent of the
total uSIDM mass in the halo. For reasonable values of , these black
holes can form at high enough redshifts to grow to quasars
by , alleviating tension within the standard CDM
cosmology. The ubiquitous formation of central black holes in halos could also
create cores in dwarf galaxies by ejecting matter during binary black hole
mergers, potentially resolving the "too big to fail" problem.Comment: submitted to Ap
Land landing couch dynamics computer program
Computer programs perform landing stability studies of mechanical impact system designs for advanced spacecraft. The programs consider variation in spacecraft vertical and horizontal velocity, attitude and orientation, shock strut load-stroke characteristics, and ground coefficient of friction
Global Change and the Earth System
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94868/1/eost14816.pd
Goethite on Mars - A laboratory study of physically and chemically bound water in ferric oxides
Thermogravimetric study of physically and chemically bound water in ferric oxides of limonite with application to goethite on Mar
Wind tunnel studies of Martian aeolian processes
Preliminary results are reported of an investigation which involves wind tunnel simulations, geologic field studies, theoretical model studies, and analyses of Mariner 9 imagery. Threshold speed experiments were conducted for particles ranging in specific gravity from 1.3 to 11.35 and diameter from 10.2 micron to 1290 micron to verify and better define Bagnold's (1941) expressions for grain movement, particularly for low particle Reynolds numbers and to study the effects of aerodynamic lift and surface roughness. Wind tunnel simulations were conducted to determine the flow field over raised rim craters and associated zones of deposition and erosion. A horseshoe vortex forms around the crater, resulting in two axial velocity maxima in the lee of the crater which cause a zone of preferential erosion in the wake of the crater. Reverse flow direction occurs on the floor of the crater. The result is a distinct pattern of erosion and deposition which is similar to some martian craters and which indicates that some dark zones around Martian craters are erosional and some light zones are depositional
Improvements in Space Geodesy Data Discovery at the CDDIS
The Crustal Dynamics Data Information System (CDDIS) supports data archiving and distribution activities for the space geodesy and geodynamics community. The main objectives of the system are to store space geodesy and geodynamics related data products in a central data bank. to maintain information about the archival of these data, and to disseminate these data and information in a timely manner to a global scientific research community. The archive consists of GNSS, laser ranging, VLBI, and DORIS data sets and products derived from these data. The CDDIS is one of NASA's Earth Observing System Data and Information System (EOSDIS) distributed data centers; EOSDIS data centers serve a diverse user community and arc tasked to provide facilities to search and access science data and products. Several activities are currently under development at the CDDIS to aid users in data discovery, both within the current community and beyond. The CDDIS is cooperating in the development of Geodetic Seamless Archive Centers (GSAC) with colleagues at UNAVCO and SIO. TIle activity will provide web services to facilitate data discovery within and across participating archives. In addition, the CDDIS is currently implementing modifications to the metadata extracted from incoming data and product files pushed to its archive. These enhancements will permit information about COOlS archive holdings to be made available through other data portals such as Earth Observing System (EOS) Clearinghouse (ECHO) and integration into the Global Geodetic Observing System (GGOS) portal
- …