51 research outputs found
Manipulation and Detection of a Trapped Yb+ Ion Hyperfine Qubit
We demonstrate the use of trapped ytterbium ions as quantum bits for quantum
information processing. We implement fast, efficient state preparation and
state detection of the first-order magnetic field-insensitive hyperfine levels
of 171Yb+, with a measured coherence time of 2.5 seconds. The high efficiency
and high fidelity of these operations is accomplished through the stabilization
and frequency modulation of relevant laser sources.Comment: 10 pages, 9 figures, 1 tabl
Effects of control temperature, ablation time, and background tissue in radiofrequency ablation of osteoid osteoma:A computer modeling study
To study the effects of the control temperature, ablation time, and the background tissue surrounding the tumor on the size of the ablation zone on radiofrequency ablation (RFA) of osteoid osteoma (OO). Finite element models of non‐cooled temperature‐controlled RFA of typical OOs were developed to determine the resulting ablation radius at control temperatures of 70, 80, and 90°C. Three different geometries were used, mimicking common cases of OO. The ablation radius was obtained by using the Arrhenius equation to determine cell viability. Ablation radii were larger for higher temperatures and also increased with time. All geometries and control temperatures tested had ablation radii larger than the tumor. The ablation radius developed rapidly in the first few minutes for all geometries and control temperatures tested, developing slowly towards the end of the ablation. Resistive heating and the temperature distribution showed differences depending on background tissue properties, resulting in differences in the ablation radius on each geometry. The ablation radius has a clear dependency not only on the properties of the tumor but also on the background tissue. Lower background tissue's electrical conductivity and blood perfusion rates seem to result in larger ablation zones. The differences observed between the different geometries suggest the need for patient‐specific planning, as the anatomical variations could cause significantly different outcomes where models like the one here presented could help to guarantee safe and successful tumor ablations
Vacuum-stimulated cooling of single atoms in three dimensions
Taming quantum dynamical processes is the key to novel applications of
quantum physics, e.g. in quantum information science. The control of
light-matter interactions at the single-atom and single-photon level can be
achieved in cavity quantum electrodynamics, in particular in the regime of
strong coupling where atom and cavity form a single entity. In the optical
domain, this requires permanent trapping and cooling of an atom in a
micro-cavity. We have now realized three-dimensional cavity cooling and
trapping for an orthogonal arrangement of cooling laser, trap laser and cavity
vacuum. This leads to average single-atom trapping times exceeding 15 seconds,
unprecedented for a strongly coupled atom under permanent observation.Comment: 4 pages, 4 figure
Shaping the Phase of a Single Photon
While the phase of a coherent light field can be precisely known, the phase
of the individual photons that create this field, considered individually,
cannot. Phase changes within single-photon wave packets, however, have
observable effects. In fact, actively controlling the phase of individual
photons has been identified as a powerful resource for quantum communication
protocols. Here we demonstrate the arbitrary phase control of a single photon.
The phase modulation is applied without affecting the photon's amplitude
profile and is verified via a two-photon quantum interference measurement,
which can result in the fermionic spatial behaviour of photon pairs. Combined
with previously demonstrated control of a single photon's amplitude, frequency,
and polarisation, the fully deterministic phase shaping presented here allows
for the complete control of single-photon wave packets.Comment: 4 pages, 4 figure
Heralded single photon absorption by a single atom
The emission and absorption of single photons by single atomic particles is a
fundamental limit of matter-light interaction, manifesting its quantum
mechanical nature. At the same time, as a controlled process it is a key
enabling tool for quantum technologies, such as quantum optical information
technology [1, 2] and quantum metrology [3, 4, 5, 6]. Controlling both emission
and absorption will allow implementing quantum networking scenarios [1, 7, 8,
9], where photonic communication of quantum information is interfaced with its
local processing in atoms. In studies of single-photon emission, recent
progress includes control of the shape, bandwidth, frequency, and polarization
of single-photon sources [10, 11, 12, 13, 14, 15, 16, 17], and the
demonstration of atom-photon entanglement [18, 19, 20]. Controlled absorption
of a single photon by a single atom is much less investigated; proposals exist
but only very preliminary steps have been taken experimentally such as
detecting the attenuation and phase shift of a weak laser beam by a single atom
[21, 22], and designing an optical system that covers a large fraction of the
full solid angle [23, 24, 25]. Here we report the interaction of single
heralded photons with a single trapped atom. We find strong correlations of the
detection of a heralding photon with a change in the quantum state of the atom
marking absorption of the quantum-correlated heralded photon. In coupling a
single absorber with a quantum light source, our experiment demonstrates
previously unexplored matter-light interaction, while opening up new avenues
towards photon-atom entanglement conversion in quantum technology.Comment: 10 pages, 4 figure
Raman spectroscopy of a single ion coupled to a high-finesse cavity
We describe an ion-based cavity-QED system in which the internal dynamics of
an atom is coupled to the modes of an optical cavity by vacuum-stimulated Raman
transitions. We observe Raman spectra for different excitation polarizations
and find quantitative agreement with theoretical simulations. Residual motion
of the ion introduces motional sidebands in the Raman spectrum and leads to ion
delocalization. The system offers prospects for cavity-assisted
resolved-sideband ground-state cooling and coherent manipulation of ions and
photons.Comment: 8 pages, 6 figure
Efficient coupling of photons to a single molecule and the observation of its resonance fluorescence
Single dye molecules at cryogenic temperatures display many spectroscopic
phenomena known from free atoms and are thus promising candidates for
fundamental quantum optical studies. However, the existing techniques for the
detection of single molecules have either sacrificed the information on the
coherence of the excited state or have been inefficient. Here we show that
these problems can be addressed by focusing the excitation light near to the
absorption cross section of a molecule. Our detection scheme allows us to
explore resonance fluorescence over 9 orders of magnitude of excitation
intensity and to separate its coherent and incoherent parts. In the strong
excitation regime, we demonstrate the first observation of the Mollow triplet
from a single solid-state emitter. Under weak excitation we report the
detection of a single molecule with an incident power as faint as 150 attoWatt,
paving the way for studying nonlinear effects with only a few photons.Comment: 6 figure
The Quantum Internet
Quantum networks offer a unifying set of opportunities and challenges across
exciting intellectual and technical frontiers, including for quantum
computation, communication, and metrology. The realization of quantum networks
composed of many nodes and channels requires new scientific capabilities for
the generation and characterization of quantum coherence and entanglement.
Fundamental to this endeavor are quantum interconnects that convert quantum
states from one physical system to those of another in a reversible fashion.
Such quantum connectivity for networks can be achieved by optical interactions
of single photons and atoms, thereby enabling entanglement distribution and
quantum teleportation between nodes.Comment: 15 pages, 6 figures Higher resolution versions of the figures can be
downloaded from the following link:
http://www.its.caltech.edu/~hjkimble/QNet-figures-high-resolutio
Cavity Induced Interfacing of Atoms and Light
This chapter introduces cavity-based light-matter quantum interfaces, with a
single atom or ion in strong coupling to a high-finesse optical cavity. We
discuss the deterministic generation of indistinguishable single photons from
these systems; the atom-photon entanglement intractably linked to this process;
and the information encoding using spatio-temporal modes within these photons.
Furthermore, we show how to establish a time-reversal of the aforementioned
emission process to use a coupled atom-cavity system as a quantum memory. Along
the line, we also discuss the performance and characterisation of cavity
photons in elementary linear-optics arrangements with single beam splitters for
quantum-homodyne measurements.Comment: to appear as a book chapter in a compilation "Engineering the
Atom-Photon Interaction" published by Springer in 2015, edited by A.
Predojevic and M. W. Mitchel
A longitudinal and cross-sectional study of Epstein-Barr virus DNA load: a possible predictor of AIDS-related lymphoma in HIV-infected patients
Introduction: HIV-infected patients are more than 100-fold greater at risk for developing malignant AIDS-related lymphoma (ARL) compared to the general population. Most ARLs are EBV related. The main purpose of this study was to investigate whether a high peak EBV DNA load in HIV-infected patients is predictive of ARL, including classical Hodgkin lymphoma. Methods: From an ongoing prospective HIV positive cohort study, we conducted a case-control study between 2004 and 2016 among patients from whom at least one EBV DNA load in serum or plasma was available. We compared peak EBV DNA load between patients with (49 cases) and without ARL (156 controls). Results: The geometric mean of the peak EBV DNA load measured before diagnosis of malignant lymphoma was 52,565 IU/mL in EBER-positive lymphoma patients vs. 127 IU/mL in controls (p 100,000 IU/mL have an increased risk for diagnosis of malignant lymphoma compared to patients with EBV DNA loads ≤100,000 IU/mL (adjusted OR 12.53; 95%CI: 4.08; 38.42). In the longitudinal study, including 13 patients with at least three left-over plasma samples available for retesting, measurements of EBV-DNA during the preceding 12 months proved to be of poor value for predicting subsequent lymphoma diagnosis. Conclusions: A EBV DNA load >100,000 IU/mL can be useful in clinical setting to accelerate time to diagnosis and treatment. EBV-DNA loads in samples taken during the preceding year of ARL diagnosis showed to be of poor predictive value
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