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Optical Quantum Memories With Cold Atomic Ensembles
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Book Synopsis Optical Quantum Memories with Cold Atomic Ensembles by : Adrien Nicolas
Download or read book Optical Quantum Memories with Cold Atomic Ensembles written by Adrien Nicolas and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present an experimental study of two optical quantum memory systems based on electromagnetically induced transparency (EIT) in cold cesium atoms.We explain the relevance of quantum memories for the development of large-scale quantum networks, we give a comprehensive theory of the EIT phenomenon and underline the role of relevant parameters regarding the implementation of quantum memories.The first system under study is prepared in a free-space magneto-optical trap. The main result of this thesis is the demonstration of the spatial multimode capability of this system at the quantum level. For this, we used Laguerre-Gaussian (LG) light beams, i.e. beams possessing a non-zero value of orbital angular momentum (OAM). In a first step, we showed that the orbital angular momentum of stored light pulses is preserved by the memory, deep in the single photon regime. In a second step, we encoded information in the orbital angular momentum state of a weak light pulse and defined a qubit using two LG beams of opposite helicities. We developed an original setup for the measurement of this OAM qubit and used it to characterize the action of the memory during the storage of such a light pulse. Our results show that the memory performs the quantum storage of such a qubit.The second system under study, also a cloud of cold atoms, has the specificity that the atoms are trapped optically in the vicinity of a nano-waveguide. This innovative design ensures a higher light-matter interaction and facilitates the interfacing of photons into and out of the memory. We describe the building of this setup and the first steps towards quantum memory implementations.
Book Synopsis Broad Bandwidth and High Dimensional Quantum Memory Based on Atomic Ensembles by : Dong-Sheng Ding
Download or read book Broad Bandwidth and High Dimensional Quantum Memory Based on Atomic Ensembles written by Dong-Sheng Ding and published by Springer. This book was released on 2017-12-26 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an experimental study of quantum memory based on cold atomic ensembles and discusses photonic entanglement. It mainly focuses on experimental research on storing orbital angular momentum, and introduces readers to methods for storing a single photon carried by an image or an entanglement of spatial modes. The thesis also discusses the storage of photonic entanglement using the Raman scheme as a step toward implementing high-bandwidth quantum memory. The storage of photonic entanglement is central to achieving long-distance quantum communication based on quantum repeaters and scalable linear optical quantum computation. Addressing this key issue, the findings presented in the thesis are very promising with regard to future high-speed and high-capacity quantum communications.
Book Synopsis Quantum Network with Multiple Cold Atomic Ensembles by : Bo Jing
Download or read book Quantum Network with Multiple Cold Atomic Ensembles written by Bo Jing and published by Springer Nature. This book was released on 2022-03-16 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the novel research in quantum memory networking, especially quantum memories based on cold atomic ensembles. After discussing the frontiers of quantum networking research and building a DLCZ-type quantum memory with cold atomic ensemble, the author develops the ring cavity enhanced quantum memory and demonstrates a filter-free quantum memory, which significantly improves the photon-atom entanglement. The author then realizes for the first time the GHZ-type entanglement of three separate quantum memories, a building block of 2D quantum repeaters and quantum networks. The author also combines quantum memories and time-resolved measurements, and reports the first multiple interference of three single photons with different colors. The book is of good reference value for graduate students, researchers, and technical personnel in quantum information sciences.
Book Synopsis Quantum Memory Protocols in Large Cold Atomic Ensembles by : Lucile Veissier
Download or read book Quantum Memory Protocols in Large Cold Atomic Ensembles written by Lucile Veissier and published by . This book was released on 2013 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum memories are an essential building block for quantum information science and in particular for the implementation of quantum communications across long distances. A quantum memory is defined as a system capable of storing and retrieving quantum states on-demand, such as quantum bits (qubits). Atomic ensembles are good candidates for this purpose because they enables strong light-matter coupling in case of a large number of atoms. Moreover, the collective effect, enhanced in the regime of large optical depth, can lead to storage efficiency close to unity. Thus, in this thesis, a large magneto-optical trap for cesium atoms is used as a atomic medium in order to implement a quantum memory protocol based on electromagnetically induced transparency (EIT). First, the EIT phenomenon is studied through a criterion for the discrimination between the EIT and the Autler-Townes splitting models. We then report on the implementation of an EIT-based memory for photonic qubits encoded in orbital angular momentum (OAM) of light. A reversible memory for Laguerre-Gaussian modes is implemented, and we demonstrate that the optical memory preserves the handedness of the helical structure at the single-photon level. Then, a full quantum state tomography of the retrieved OAM encoded qubits is performed, giving fidelities above the classical bound. This showed that our optical memory operates in the quantum regime. Finally, we present the implementation of the so-called DLCZ protocol in our ensemble of cold atoms, enabling the generation of heralded single photons. A homodyne detection setup allows us to realize the quantum tomography of the created photonic state.
Book Synopsis Investigations of Memory, Entanglement, and Long-range Interactions Using Ultra-cold Atoms by : Yaroslav Dudin
Download or read book Investigations of Memory, Entanglement, and Long-range Interactions Using Ultra-cold Atoms written by Yaroslav Dudin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-term storage of quantum information has diverse applications in quantum information science. This work presents an experimental realization of quantum memories with lifetimes greater then 0.1 s. The memories are based on cold rubidium atoms confined in one-dimensional optical lattices. First realization of lattice-based quantum memory and entanglement between a light field and a spin wave is presented in Chapter II. Chapter III describes two different methods (two-photon and magnetic) of compensation for inhomogeneous differential light shifts between the memory levels due to optical trapping potentials, and demonstration of entanglement between a telecom-band light field and a light-shift compensated memory qubit. Highly excited Rydberg atoms present a unique platform for study of strongly correlated systems and quantum information, because of their enormous dipole moments and consequent strong, long-range interactions. In the experiment described in Chapter IV single collective Rydberg excitations are created in a cold atomic gas. After a variable storage period the excitations are converted into light. As the principal quantum number n of the Rydberg level is increased beyond ~ 70, no more than a single excitation is retrieved from the entire mesoscopic ensemble of atoms. In Chapter V, by spatially selective conversion of the spin wave into a light field, we demonstrate that Rydberg-level interactions create long-range correlations of collective atomic excitations. These results hold promise for studies of dynamics and disorder in many-body systems with tunable interactions and for scalable quantum information networks. Chapter VI presents initial observations of coherent many-body Rabi oscillations between the ground level and a Rydberg level using several hundred cold rubidium atoms. The strongly pronounced oscillations indicate a nearly complete excitation blockade of the entire mesoscopic ensemble by a single excited atom.
Book Synopsis Long Distance Entanglement Between Quantum Memories by : Yong Yu
Download or read book Long Distance Entanglement Between Quantum Memories written by Yong Yu and published by Springer Nature. This book was released on 2023-01-01 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights novel research work done on cold atom-based quantum networks. Given that one of the main challenges in building the quantum network is the limited entanglement distribution distance, this book presents some state-of-the-art experiments in tackling this challenge and, for the first time, establishes entanglement between quantum memories via metropolitan-scale fiber transmission. This achievement is accomplished by cooperating high-efficiency cold quantum memories, low-loss quantum frequency conversion modules, and long-fiber phase-locking techniques. In the book, the scheme design, experimental setup, data analyses, and numerous technical details are given. Therefore, it suits a broad readership that includes all students, researchers, and technicians who work in quantum information sciences.
Book Synopsis Quantum Information with Continuous Variables of Atoms and Light by : N. J. Cerf
Download or read book Quantum Information with Continuous Variables of Atoms and Light written by N. J. Cerf and published by World Scientific. This book was released on 2007 with total page 629 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum information describes the new field which bridges quantum physics and information science. The quantum world allows for completely new architectures and protocols. While originally formulated in continuous quantum variables, the field worked almost exclusively with discrete variables, such as single photons and photon pairs. The renaissance of continuous variables came with European research consortia such as ACQUIRE (Advanced Coherent Quantum Information Research) in the late 1990s, and QUICOV (Quantum Information with Continuous Variables) from 2000OCo2003. The encouraging research results of QUICOV and the new conference series CVQIP (Continuous Variable Quantum Information Processing) triggered the idea for this book. This book presents the state of the art of quantum information with continuous quantum variables. The individual chapters discuss results achieved in QUICOV and presented at the first five CVQIP conferences from 2002OCo2006. Many world-leading scientists working on continuous variables outside Europe also contribute to the book.
Book Synopsis Quantum Interferometry in Phase Space by : Martin Suda
Download or read book Quantum Interferometry in Phase Space written by Martin Suda and published by Springer Science & Business Media. This book was released on 2006 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Quantum Interferometry in Phase Space" is primarily concerned with quantum-mechanical distribution functions and their applications in quantum optics and neutron interferometry. In the first part of the book, the author describes the phase-space representation of quantum optical phenomena such as coherent and squeezed states. Applications to interferometry, e.g. in beam splitters and fiber networks, are also presented. In the second part of the book, the theoretical formalism is applied to neutron interferometry, including the dynamical theory of diffraction, coherence properties of superposed beams, and dephasing effects.
Book Synopsis Quantum Dot Ensembles as an Optical Quantum Memory by : Michael Woodhouse
Download or read book Quantum Dot Ensembles as an Optical Quantum Memory written by Michael Woodhouse and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Alice in Quantumland by : Robert Gilmore
Download or read book Alice in Quantumland written by Robert Gilmore and published by Springer Science & Business Media. This book was released on 1995-07-21 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this cleverly conceived book, physicist Robert Gilmore makes accessible some complex concepts in quantum mechanics by sending Alice to Quantumland-a whole new Wonderland, smaller than an atom, where each attraction demonstrates a different aspect of quantum theory. Alice unusual encounters, enhanced by illustrations by Gilmore himself, make the Uncertainty Principle, wave functions, the Pauli Principle, and other elusive concepts easier to grasp.
Book Synopsis The Quantum World of Ultra-Cold Atoms and Light Book II: The Physics of Quantum-Optical Devices by : Crispin Gardiner
Download or read book The Quantum World of Ultra-Cold Atoms and Light Book II: The Physics of Quantum-Optical Devices written by Crispin Gardiner and published by World Scientific Publishing Company. This book was released on 2015-04-24 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: This century has seen the development of technologies for manipulating and controlling matter and light at the level of individual photons and atoms, a realm in which physics is fully quantum-mechanical. The dominant experimental technology is the laser, and the theoretical paradigm is quantum optics. The Quantum World of Ultra-Cold Atoms and Light is a trilogy, which presents the quantum optics way of thinking and its applications to quantum devices. This book — The Physics of Quantum-Optical Devices — provides a comprehensive treatment of theoretical quantum optics. It covers applications to the optical manipulation of the quantum states of atoms, laser cooling, continuous measurement, quantum computers and quantum processors, superconducting systems and quantum networks. The subject is consistently formulated in terms of quantum stochastic techniques, and a systematic and thorough development of these techniques is a central part of the book. There is also a compact overview of the ideas of quantum information theory. The main aim of the book is to present the theoretical techniques necessary for the understanding of quantum optical devices, with special attention to those devices used in quantum information processing and quantum simulation. Although these techniques were developed originally for the optical regime, they are also applicable to electromagnetic radiation from the microwave realm to the ultra-violet, and for atomic systems, Josephson junction systems, quantum dots and nano-mechanical systems. For more information, please visit: http://europe.worldscientific.com/quantum-world-of-ultra-cold-atoms-and-light.html
Book Synopsis Atom-light Interfaces for Quantum Information Processing by : Jesse Llewellyn Everett
Download or read book Atom-light Interfaces for Quantum Information Processing written by Jesse Llewellyn Everett and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergence of quantum physics from the page to the lab and the world at large is an exciting development of recent years. The prospects of absolutely secure communication and efficient simulation of physical systems have spurred great human effort into understanding these possibilities and turning them into realities. Photons are the most easily manipulated quantum particles and are a promising candidate for implementing these technologies. Limitations of photons include the difficulty of keeping objects that move at the speed of light, and producing strong interactions between particles that do not normally interact. The work presented in this thesis is motivated by the possibility of overcoming these limitations. The ability to faithfully store and reproduce a quantum state is essential for many quantum information technologies. Quantum memories for light have been developed over the last two decades to provide this ability. The group at the Australian National University developed the gradient echo memory (GEM): A quantum state of light can be controllably stored and released from an atomic ensemble by the use of additional optical fields and magnetic field gradients. This scheme was previously shown to preserve the quantum characteristics of the light. We used the GEM scheme with a cold rubidium ensemble to create the first optical memory that simultaneously beat the no-cloning limit, a benchmark for many of the technologies relying on quantum memories, and the loss rate for a delay line composed of optical fibre. We also created an analogue to a pulsed optical resonator using GEM with a warm rubidium vapour. This was done by replacing the circulating optical field of a resonator with light stored in the memory, and replacing the coupling of light into and out of that circulating mode with storage and recall from the memory. The bandwidth and repetition rate of this resonator were rapidly tunable as they were controlled by external optical and magnetic fields. We worked on implementing GEM with strings of thousands of atoms strongly coupled to the evanescent field of an optical nanofibre. This raised new possibilities for creating a true random access memory that would allow a more flexible use of the multi-mode capacity of GEM. We developed the theory for a novel type of stationary light in the gradient echo memory. Our stationary light scheme relies on the destructive interference of counter-propagating optical fields throughout the memory. The optical intensity scales with optical depth, as with other forms of stationary light. However, as the destructive interference could be set up over a much greater distance, more of the optical depth is available for generating stationary light. Finally, we studied how a control-phase gate for single-photon optical states could be implemented using a nonlinear interaction with stationary light. The stationary light generated by one state modulates the phase of another state stored in the memory. The second state modifies the stationary light, also producing a back-action on the first state and generating the required cross-phase shift.
Book Synopsis Quantum memory with atomic ensembles of rubidium and single photons for long distance quantum communication by : Thorsten Strassel
Download or read book Quantum memory with atomic ensembles of rubidium and single photons for long distance quantum communication written by Thorsten Strassel and published by . This book was released on 2008 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Quantum Memory Protocols for Photonic Solid-state Devices by : Kutlu Kutluer
Download or read book Quantum Memory Protocols for Photonic Solid-state Devices written by Kutlu Kutluer and published by . This book was released on 2018 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: A photonic quantum memory (QM) is a device that has the capability of storing a quantum state of light and retrieving back after a controlled time. It is an important element in quantum information science and is, among other applications, a crucial device for quantum repeater architectures which have been proposed to overcome the loss and the decoherence issues in long distance transmission of photons. Rare earth ion doped solid state systems are promising candidates for QMs which combine the advantages of solid state systems, such as scalability and reduced experimental complexity, with the long coherence time typically found in atomic systems. In this thesis, I investigated three different QM protocols in a Pr3+:Y2SiO5 crystal. The first part describes here the first demonstration of the spectral hole memory (SHoMe) protocol which was proposed theoretically in 2009. This protocol relies on slowing down the light in a long-lived spectral hole and transferring the excitations to the spin state. We first prepare a spectral hole, then send an input pulse whose bandwidth is comparable with the hole and stop the compressed light in the crystal by transferring the off-resonant coherence to the spin state with an optical p pulse. Later a second p pulse transfers the coherence back and leads to the emission of the stored light. We reached a storage and retrieval efficiency of around 40% in the classical regime, and of 31% in the single photon level, with a signal-to-noise ratio of 33 ± 4 for a mean input photon number of 1. These results demonstrate the most efficient and noiseless spin-wave solid-state optical memory at the single photon level to date. The second part of the thesis describes new experiments using the well-known atomic frequency comb (AFC) protocol. It is based on tailoring the inhomogeneously broadened absorption profile of the rare earth with periodic absorptive peaks, which induces the re-emission of the absorbed light field after a certain time determined by the separation between the peaks. In this chapter I describe several AFC experiments. First I present the storage of frequency converted telecom photons into our crystal where we obtained a total efficiency of 1.9 ± 0.2 % for a storage time of 1.6 μs storage time and signal-to-noise ratio of more than 200 for a mean input photon number of 1. Then I discuss the results of improved excited state storage efficiency values for long storage times where we achieved 30% at short storage times and up to 17% at 10 μs storage time. And finally I present a spin-wave AFC experiment where we obtained a signal-to-noise ratio value of 28 ± 8 for a mean input photon number of 1, the highest value achieved so far for this kind of experiment. Finally, in the last part, I describe the first demonstration of a solid-state photon pair source with embedded multimode quantum memory. The aim of the protocol is to combine a single photon source and a QM in one ensemble as in the well-known Duan-Lukin-Zoller-Cirac (DLCZ) scheme however this time not in a cold atomic ensemble but in a solid-state crystal. The protocol takes advantage of the AFC protocol for rephasing the ions and obtaining efficient read-out. The use of AFC also makes the protocol temporally multi-mode. In the experiment, after the AFC preparation we send an on-resonant write pulse and detect the decayed Stokes photons which herald single spin excitations. At a later time a read pulse transfers the spin excitation back to the excited state and we detect the anti-Stokes photons. We show strong non-classical second order cross-correlations between the Stokes and anti-Stokes photons and demonstrate storage of 11 temporal modes. The results presented in this thesis represent a significant contribution to the field of solid-state quantum memories and an important steps towards the realization of scalable quantum network architectures with solid state systems.
Book Synopsis Pushing the Frontiers of Atomic Physics by : Robin Ct
Download or read book Pushing the Frontiers of Atomic Physics written by Robin Ct and published by World Scientific. This book was released on 2009 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book highlights the state of the art of the booming field of atomic physics in the early 21st century. It contains the majority of the invited papers from an ongoing series of conferences, held every two years, devoted to forefront research and fundamental studies in basic atomic physics, broadly defined. This conference, held at the University of Connecticut in July 2008, is part of a series of conferences, which began in 1968 and had its historical origins in the molecular beam conferences of the I. I. Rabi group. It provides an archival and up-to-date summary of current research on atoms and simple molecules as well as their interactions with each other and with external fields, including degenerate Bose and Fermi quantum gases and interactions involving ultrafast lasers, strong field control of X-ray processes, and nanoscale and mesoscopic quantum systems. The work of three recent Nobel Laureates in atomic physics is included, beginning with a lecture by Eric Cornell on ?When Is a Quantum Gas a Quantum Liquid??. There are also papers by Laureates Steven Chu and Roy Glauber. The volume also contains the IUPAP Young Scientist Prize lecture by Cheng Chin on ?Exploring Universality of Few-Body Physics Based on Ultracold Atoms Near Feshbach Resonances?.
Book Synopsis Advances in Atomic, Molecular, and Optical Physics by :
Download or read book Advances in Atomic, Molecular, and Optical Physics written by and published by Academic Press. This book was released on 2018-06-09 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Atomic, Molecular, and Optical Physics, Volume 67, provides a comprehensive compilation of recent developments in a field that is in a state of rapid growth. Topics covered include related applied areas, such as atmospheric science, astrophysics, surface physics, and laser physics, with timely articles written by distinguished experts that contain relevant review materials and detailed descriptions of important developments in the field. Presents the work of international experts in the field Contains comprehensive articles that compile recent developments in a field that is experiencing rapid growth, with new experimental and theoretical techniques emerging Ideal for users interested in optics, excitons, plasmas and thermodynamics Topics covered include atmospheric science, astrophysics, and surface and laser physics, amongst others
Book Synopsis Semiconductor Nanophotonics by : Michael Kneissl
Download or read book Semiconductor Nanophotonics written by Michael Kneissl and published by Springer Nature. This book was released on 2020-03-10 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the state-of-the-art in the development of semiconductor nanostructures and nanophotonic devices. It covers epitaxial growth processes for GaAs- and GaN-based quantum dots and quantum wells, describes the fundamental optical, electronic, and vibronic properties of nanomaterials, and addresses the design and realization of various nanophotonic devices. These include energy-efficient and high-speed vertical cavity surface emitting lasers (VCSELs) and ultra-small metal-cavity nano-lasers for applications in multi-terabus systems; silicon photonic I/O engines based on the hybrid integration of VCSELs for highly efficient chip-to-chip communication; electrically driven quantum key systems based on q-bit and entangled photon emitters and their implementation in real information networks; and AlGaN-based deep UV laser diodes for applications in medical diagnostics, gas sensing, spectroscopy, and 3D printing. The experimental results are accompanied by reviews of theoretical models that describe nanophotonic devices and their base materials. The book details how optical transitions in the active materials, such as semiconductor quantum dots and quantum wells, can be described using a quantum approach to the dynamics of solid-state electrons under quantum confinement and their interaction with phonons, as well as their external pumping by electrical currents. With its broad and detailed scope, this book is indeed a cutting-edge resource for researchers, engineers and graduate-level students in the area of semiconductor materials, optoelectronic devices and photonic systems.
