86 research outputs found
A solid state spin-wave quantum memory for time-bin qubits
We demonstrate the first solid-state spin-wave optical quantum memory with
on-demand read-out. Using the full atomic frequency comb scheme in a \PrYSO
crystal, we store weak coherent pulses at the single-photon level with a signal
to noise ratio . Narrow-band spectral filtering based on spectral hole
burning in a second \PrYSO crystal is used to filter out the excess noise
created by control pulses to reach an unconditional noise level of photons per pulse. We also report spin-wave storage of
photonic time-bin qubits with conditional fidelities higher than a measure and
prepare strategy, demonstrating that the spin-wave memory operates in the
quantum regime. This makes our device the first demonstration of a quantum
memory for time-bin qubits, with on demand read-out of the stored quantum
information. These results represent an important step for the use of
solid-state quantum memories in scalable quantum networks.Comment: 10 pages, 10 figure
Coherent Storage of Temporally Multimode Light Using a Spin-Wave Atomic Frequency Comb Memory
We report on coherent and multi-temporal mode storage of light using the full
atomic frequency comb memory scheme. The scheme involves the transfer of
optical atomic excitations in Pr3+:Y2SiO5 to spin-waves in the hyperfine levels
using strong single-frequency transfer pulses. Using this scheme, a total of 5
temporal modes are stored and recalled on-demand from the memory. The coherence
of the storage and retrieval is characterized using a time-bin interference
measurement resulting in visibilities higher than 80%, independent of the
storage time. This coherent and multimode spin-wave memory is promising as a
quantum memory for light.Comment: 17 pages, 5 figure
Quantum storage of polarization qubits in birefringent and anisotropically absorbing materials
Storage of quantum information encoded into true single photons is an
essential constituent of long-distance quantum communication based on quantum
repeaters and of optical quantum information processing. The storage of
photonic polarization qubits is, however, complicated by the fact that many
materials are birefringent and have polarization-dependent absorption. Here we
present and demonstrate a simple scheme that allows compensating for these
polarization effects. The scheme is demonstrated using a solid-state quantum
memory implemented with an ensemble of rare-earth ions doped into a biaxial
yttrium orthosilicate () crystal. Heralded single photons generated
from a filtered spontaneous parametric downconversion source are stored, and
quantum state tomography of the retrieved polarization state reveals an average
fidelity of , which is significantly higher than what is
achievable with a measure-and-prepare strategy.Comment: 7 pages, 3 figures, 1 table, corrected typos and added ref. 3
Quantum Storage of a Photonic Polarization Qubit in a Solid
We report on the quantum storage and retrieval of photonic polarization
quantum bits onto and out of a solid state storage device. The qubits are
implemented with weak coherent states at the single photon level, and are
stored for 500 ns in a praseodymium doped crystal with a storage and retrieval
efficiency of 10%, using the atomic frequency comb scheme. We characterize the
storage by using quantum state tomography, and find that the average
conditional fidelity of the retrieved qubits exceeds 95% for a mean photon
number mu=0.4. This is significantly higher than a classical benchmark, taking
into account the Poissonian statistics and finite memory efficiency, which
proves that our device functions as a quantum storage device for polarization
qubits, even if tested with weak coherent states. These results extend the
storage capabilities of solid state quantum memories to polarization encoding,
which is widely used in quantum information science.Comment: 6 pages, 6 figures, 1 table. New reference adde
Quantum storage of heralded single photons in a praseodymium-doped crystal
We report on experiments demonstrating the reversible mapping of heralded single photons to long-lived collective optical atomic excitations stored in a Pr3+:Y2SiO5 crystal. A cavity-enhanced spontaneous down-conversion source is employed to produce widely nondegenerate narrow-band (≈2 MHz) photon pairs. The idler photons, whose frequency is compatible with telecommunication optical fibers, are used to herald the creation of the signal photons, compatible with the Pr3þ transition. The signal photons are stored and retrieved using the atomic frequency comb protocol. We demonstrate storage times up to 4.5 μs while preserving nonclassical correlations between the heralding and the retrieved photon. This is more than 20 times longer than in previous realizations in solid state devices, and implemented in a system ideally suited for the extension to spin-wave storage
Photonic quantum state transfer between a cold atomic gas and a crystal
Interfacing fundamentally different quantum systems is key to build future
hybrid quantum networks. Such heterogeneous networks offer superior
capabilities compared to their homogeneous counterparts as they merge
individual advantages of disparate quantum nodes in a single network
architecture. However, only very few investigations on optical
hybrid-interconnections have been carried out due to the high fundamental and
technological challenges, which involve e.g. wavelength and bandwidth matching
of the interfacing photons. Here we report the first optical quantum
interconnection between two disparate matter quantum systems with photon
storage capabilities. We show that a quantum state can be faithfully
transferred between a cold atomic ensemble and a rare-earth doped crystal via a
single photon at telecommunication wavelength, using cascaded quantum frequency
conversion. We first demonstrate that quantum correlations between a photon and
a single collective spin excitation in the cold atomic ensemble can be
transferred onto the solid-state system. We also show that single-photon
time-bin qubits generated in the cold atomic ensemble can be converted, stored
and retrieved from the crystal with a conditional qubit fidelity of more than
. Our results open prospects to optically connect quantum nodes with
different capabilities and represent an important step towards the realization
of large-scale hybrid quantum networks
Cold atoms in space: community workshop summary and proposed road-map
We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies
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Cold atoms in space: community workshop summary and proposed road-map
We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies
Cold atoms in space: community workshop summary and proposed road-map
We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.publishedVersio
The reflection of the attitudes and learning processes to learning environments with authentic tasks in life science class
The purpose of this study was to determine the reflections of authentic task-based learning environments upon students' learning processes and attitudes regarding the course of Life Science. In the study, which was designed in mixed model, the embedded experimental design was used. The study was carried out in an elementary school third-grade class and conducted in five weeks. The research data were collected via the Attitude Scale for Life Science Course, observations and video records, and semi-structured interviews held with the teacher, students and parents. In this respect, the results demonstrated that authentic task-based learning environments had positive influence on the students' attitudes towards the course of Life Science. In addition, it was found that in authentic task-based learning environments, the students applied higher-order thinking skills, developed different viewpoints, shared their real-life experiences, made related reflections, benefited from the primary sources, studies cooperatively, maintained communication with their friends out of class environment, undertook multiple roles, associated the authentic context with their own lives, and made use of experts' experiences in real life. Besides all, it was concluded that the students and their parents generally reported positive views about the use of authentic task-based learning environments and found the current application effective. © 2018 Pegem Akademi Yayincilik Egitim Danismanlik Hizmetleri
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