Modeling lossy propagation of non-classical light (2009)
The lossy propagation law (generalization of Lambert-Beer's law for classical radiation loss) for non-classical, dual-mode entangled states is derived from first principles, using an infinite-series...
Signaling, Entanglement, and Quantum Evolution Beyond Cauchy Horizons (2004)
Yurtsever, Ulvi, Hockney, George
Consider a bipartite entangled system half of which falls through the event horizon of an evaporating black hole, while the other half remains coherently accessible to experiments in the exterior...
Spedalieri, Federico M., Lee, Hwang, Florescu, Marian, Kapale, Kishore T., Yurtsever, Ulvi, Dowling, Jonathan P.
We devise a new technique to enhance transmission of quantum information through linear optical quantum information processors. The idea is based on applying the Quantum Zeno effect to the process of...
Signaling and the Black Hole Final State (2004)
Yurtsever, Ulvi, Hockney, George
In an attempt to restore the unitarity of the evaporation process, Horowitz and Maldacena recently proposed a boundary-condition constraint for the final quantum state of an evaporating black hole at...
Causality, Entanglement, and Quantum Evolution Beyond Cauchy Horizons (2003)
Yurtsever, Ulvi, Hockney, George
We consider a bipartite entangled system half of which falls through the event horizon of an evaporating black hole, while the other half remains coherently accessible to experiments in the exterior...
Gravitational decoherence (2003)
We investigate the effect of quantum metric fluctuations on qubits that are gravitationally coupled to a background spacetime. In our first example, we study the propagation of a qubit in flat...
The Holographic Entropy Bound and Local Quantum Field Theory (2003)
The maximum entropy that can be stored in a bounded region of space is in dispute: it goes as volume, implies (non-gravitational) microphysics; it goes as the surface area, asserts the "holographic...
Complex worlds from simple rules? (2002)
Can the apparent complexity we observe in the real world be generated from simple initial conditions via simple, deterministic rules?
Distributed entanglement as a probe for the quantum structure of spacetime (2002)
Kok, Pieter, Yurtsever, Ulvi, Braunstein, Samuel L., Dowling, Jonathan P.
Simultaneity is a well-defined notion in special relativity once a Minkowski metric structure is fixed on the spacetime continuum (manifold) of events. In quantum gravity, however, the metric is not...
Interferometry with Entangled Atoms (2001)
A quantum gravity-gradiometer consists of two spatially separated ensembles of atoms interrogated by pulses of a common laser beam. Laser pulses cause the probability amplitudes of atomic...
Yurtsever, Ulvi, Dowling, Jonathan P.
Recent work has raised the possibility that quantum information theory techniques can be used to synchronize atomic clocks nonlocally. One of the proposed algorithms for quantum clock synchronization...
Ultra-Precise Clock Synchronization via Distant Entanglement (1998)
Shahriar, Selim, Wong, Franco, Yurtsever, Ulvi
We have demonstrated a spectrally bright source of entangled photon pairs that are necessary for transferring entanglement from photons to a pair of atoms at significant distance. We have shown how a...
Quantum Mechanics and Algorithmic Randomness (1998)
A long sequence of tosses of a classical coin produces an apparently random bit string, but classical randomness is an illusion: the algorithmic information content of a classically-generated bit...
A note on the averaged null energy condition in quantum field theory (1995)
The averaged null energy condition has been recently shown to hold for linear quantum fields in a large class of spacetimes. Nevertheless, it is easy to show by using a simple scaling argument that...
Geometry of chaos in the two-center problem in General Relativity (1994)
The now-famous Majumdar-Papapetrou exact solution of the Einstein-Maxwell equations describes, in general, $N$ static, maximally charged black holes balanced under mutual gravitational and...
The averaged null energy condition and difference inequalities in quantum field theory (1994)
Recently, Larry Ford and Tom Roman have discovered that in a flat cylindrical space, although the stress-energy tensor itself fails to satisfy the averaged null energy condition (ANEC) along the...
A remark on kinks and time machines (1994)
We describe an elementary proof that a manifold with the topology of the Politzer time machine does not admit a nonsingular, asymptotically flat Lorentz metric.
The origin of spacetime topology and generalizations of quantum field theory (1993)
The research effort reported in this paper is directed, in a broad sense, towards understanding the small-scale structure of spacetime. The fundamental question that guides our discussion is ``what...
Algebraic approach to quantum field theory on non-globally-hyperbolic spacetimes (1993)
The mathematical formalism for linear quantum field theory on curved spacetime depends in an essential way on the assumption of global hyperbolicity. Physically, what lie at the foundation of any...
Cauchy problem in spacetimes with closed timelike curves (1990)
Friedman, John, Morris, Michael S., Novikov, Igor D., Echeverria, Fernando, Klinkhammer, Gunnar, Thorne, Kip S., ...
The laws of physics might permit the existence, in the real Universe, of closed timelike curves (CTC’s). Macroscopic CTC’s might be a semiclassical consequence of Planck-scale, quantum...
Singularities and horizons in the collisions of gravitational waves (1989)
It is well known that when gravitational plane waves propagating and colliding in an otherwise flat background interact they produce singularities. In this paper we explore the structure of the...
Wormholes, time machines, and the weak energy condition (1988)
Morris, Michael S., Thorne, Kip S., Yurtsever, Ulvi
It is argued that, if the laws of physics permit an advanced civilization to create and maintain a wormhole in space for interstellar travel, then that wormhole can be converted into a time machine...