Model-independent Higgs coupling measurements at the LHC using the H \to ZZ \to 4l lineshape

We show that combining a direct measurement of the Higgs total width from the H \to ZZ \to 4l lineshape with Higgs signal rate measurements allows Higgs couplings to be extracted in a model-independent way from CERN Large Hadron Collider (LHC) data. Using existing experimental studies with 30 fb-1 at one detector of the 14 TeV LHC, we show that the couplings-squared of a 190 GeV Higgs to WW, ZZ, and gg can be extracted with statistical precisions of about 10%, and a 95% confidence level upper limit on an unobserved component of the Higgs decay width of about 22% of the SM Higgs width can be set. The method can also be applied for heavier Higgs masses.Comment: 11 pages, 4 figure

Observation of genuine three-photon interference

Multiparticle quantum interference is critical for our understanding and exploitation of quantum information, and for fundamental tests of quantum mechanics. A remarkable example of multi-partite correlations is exhibited by the Greenberger-Horne-Zeilinger (GHZ) state. In a GHZ state, three particles are correlated while no pairwise correlation is found. The manifestation of these strong correlations in an interferometric setting has been studied theoretically since 1990 but no three-photon GHZ interferometer has been realized experimentally. Here we demonstrate three-photon interference that does not originate from two-photon or single photon interference. We observe phase-dependent variation of three-photon coincidences with 90.5 \pm 5.0 % visibility in a generalized Franson interferometer using energy-time entangled photon triplets. The demonstration of these strong correlations in an interferometric setting provides new avenues for multiphoton interferometry, fundamental tests of quantum mechanics and quantum information applications in higher dimensions.Comment: 7 pages, 7 figure

Room temperature quantum bit storage exceeding 39 minutes using ionized donors in 28-silicon

Quantum memories capable of storing and retrieving coherent information for extended times at room temperature would enable a host of new technologies. Electron and nuclear spin qubits using shallow neutral donors in semiconductors have been studied extensively but are limited to low temperatures ($\le$10 K); however, the nuclear spins of ionized donors have potential for high temperature operation. We use optical methods and dynamical decoupling to realize this potential for an ensemble of 31P donors in isotopically purified 28Si and observe a room temperature coherence time of over 39 minutes. We further show that a coherent spin superposition can be cycled from 4.2 K to room temperature and back, and report a cryogenic coherence time of 3 hours in the same system.Comment: 5 pages, 4 figure

Nonlinear Optics: The Enabling Technology for Quantum Information Science

Nonlinear optical processes such as parametric down conversion and squeezed light generation are key elements of most quantum protocols, leading to crucial applications such as quantum imaging, sub-shot-noise metrology, and secure communication