Physical Review Letters

Teklemariam, G; Fortunato, E. M; Pravia, M. A; Havel, T. F; Cory, D. G

doi: 10.1103/PhysRevLett.86.5845pmid: 11415376

We report the implementation of a three-spin quantum disentanglement eraser on a liquid-state NMR quantum information processor. A key feature of this experiment was its use of pulsed magnetic field gradients to mimic projective measurements. This ability is an important step towards the development of an experimentally controllable system which can simulate any quantum dynamics, both coherent and decoherent.

Abel, S; Khalil, S; Lebedev, O

doi: 10.1103/PhysRevLett.86.5850pmid: 11415377

We analyze the possibility of simultaneous electron, neutron, and mercury electric dipole moment (EDM) cancellations in the mSUGRA and D-brane models. We find that the mercury EDM constraint practically rules out the cancellation scenario in D-brane models, whereas in the context of mSUGRA it is still allowed with some fine tuning.

Chattopadhyay, Utpal

doi: 10.1103/PhysRevLett.86.5854pmid: 11415378

We analyze the implications of the new physics effect seen in the g - 2 Brookhaven measurement and show that if the effect arises from supersymmetry, then the sign of the Higgs mixing parameter μ is determined to be positive in the standard sign convention. Further, analyses within the minimal supergravity model show that the Brookhaven result leads to upper limits on the universal gaugino and scalar masses of m 1 / 2 ≤ 800 GeV and m 0 ≤ 1.5 TeV for tan β ≤ 55 . Our analysis strongly suggests that supersymmetry via production of sparticles must be found at the CERN Large Hadron Collider. Further, sgn ( μ ) positive is favorable for the discovery of supersymmetric cold dark matter.

Girlanda, L; Stern, J; Talavera, P

doi: 10.1103/PhysRevLett.86.5858pmid: 11415379

We propose a method for implementing the large- N c , large- N f limit of QCD at the effective Lagrangian level. Depending on the value of the ratio N f / N c , different patterns of chiral symmetry breaking can arise, leading in particular to different behaviors of the η ′ mass in the combined large- N limit.

Ermisch, K; van den Berg, A. M; Bieber, R. M; Glöckle, W. M; Golak, J. M; Hagemann, M. M; Hannen, V. M; Harakeh, M. N; de Huu, M. A; Kalantar-Nayestanaki, N. A; Kamada, H. A; Kiš, M. A; Kuroś-Żołnierczuk, J. A; Mahjour-Shafiei, M. A; Micherdzińska, A. A;

Ødegård, S. W; Hagemann, G. B; Jensen, D. R; Bergström, M. R; Herskind, B. R; Sletten, G. R; Törmänen, S. R; Wilson, J. N; Tjøm, P. O; Hamamoto, I. O; Spohr, K. O; Hübel, H. O; Görgen, A. O; Schönwasser, G. O; Bracco, A. O; Leoni, S. O;

Meyer, V; Rowe, M. A; Kielpinski, D. A; Sackett, C. A; Itano, W. M; Monroe, C. M; Wineland, D. J

doi: 10.1103/PhysRevLett.86.5870pmid: 11415382

We experimentally investigate three methods, utilizing different atomic observables and entangled states, to increase the sensitivity of rotation angle measurements beyond the “standard quantum limit” for nonentangled states. All methods use a form of quantum mechanical “squeezing.” In a system of two entangled trapped 9 Be + ions we observe a reduction in uncertainty of rotation angle below the standard quantum limit for all three methods including all sources of noise. As an application, we demonstrate an increase in precision of frequency measurement in a Ramsey spectroscopy experiment.

Carney, P. Scott; Markel, Vadim A; Schotland, John C

doi: 10.1103/PhysRevLett.86.5874pmid: 11415383

We investigate the near-field inverse scattering problem with evanescent waves. An analytic solution to this problem within the weak-scattering approximation is used to show that the usual Rayleigh limit may be overcome even when measurements are made without phase information. Applications to a novel form of three-dimensional microscopy with subwavelength resolution are described.

Patil, D. J; Hunt, Brian R; Kalnay, Eugenia R; Yorke, James A; Ott, Edward A

doi: 10.1103/PhysRevLett.86.5878pmid: 11415384

A statistic, the BV (bred vector) dimension, is introduced to measure the effective local finite-time dimensionality of a spatiotemporally chaotic system. It is shown that the Earth’s atmosphere often has low BV dimension, and the implications for improving weather forecasting are discussed.

Dhar, Abhishek

doi: 10.1103/PhysRevLett.86.5882pmid: 11415385

A general formulation is developed to study heat conduction in disordered harmonic chains with arbitrary heat baths, satisfying the fluctuation-dissipation theorem. A simple formal expression for the heat current J is obtained, from which its asymptotic system-size ( N ) dependence is extracted. It is shown that “thermal conductivity” depends not just on the system itself but also on the spectral properties of the heat baths. As special cases we recover earlier results that gave J ∼ 1 / N 3 / 2 for fixed boundaries and J ∼ 1 / N 1 / 2 for free boundaries. Other choices give other power laws including the “Fourier behavior” J ∼ 1 / N .