The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Jyrki Piilo - One of the best experts on this subject based on the ideXlab platform.
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entanglement distribution in optical fibers assisted by Nonlocal Memory effects
EPL, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:The successful implementation of several quantum information and communication protocols requires distributing entangled pairs of quantum bits in a reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory effects for quantum information tasks are still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in an efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least a 12-fold improvement in the channel, or fiber length, for preserving the highly entangled initial polarization states of photons against dephasing.
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Nonlocal Memory assisted entanglement distribution in optical fibers
EPL (Europhysics Letters), 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:Successful implementation of several quantum information and communication protocols require distributing entangled pairs of quantum bits in reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory-effects for quantum information tasks is still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least 12-fold improvement in the channel, or fiber length, for preserving the highly-entangled initial polarization states of photons against dephasing.
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Nonlocal Memory effects allow perfect teleportation with mixed states
Scientific Reports, 2014Co-Authors: Elsi-mari Laine, Heinz-peter Breuer, Jyrki PiiloAbstract:One of the most striking consequences of quantum physics is quantum teleportation – the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of Nonlocal Memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that Memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks.
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Memory Assisted Entanglement Distribution in Optical Fibers
Research in Optical Sciences, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Laine Elsi, Jyrki PiiloAbstract:we show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within optical fibers.
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Photonic realization of Nonlocal Memory effects and non-Markovian quantum probes
Scientific Reports, 2013Co-Authors: Bi-heng Liu, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Dong-yang Cao, Yun-feng Huang, Jyrki PiiloAbstract:The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. Recent developments in this field have increased our basic understanding on how non-Markovian effects influence the dynamics of an open quantum system, paving the way to exploit Memory effects for various quantum control tasks. Most often, the environment of an open system is thought to act as a sink for the system information. However, here we demonstrate experimentally that a photonic open system can exploit the information initially held by its environment. Correlations in the environmental degrees of freedom induce Nonlocal Memory effects where the bipartite open system displays, counterintuitively, local Markovian and global non-Markovian character. Our results also provide novel methods to protect and distribute entanglement, and to experimentally quantify correlations in photonic environments.
Elsi-mari Laine - One of the best experts on this subject based on the ideXlab platform.
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entanglement distribution in optical fibers assisted by Nonlocal Memory effects
EPL, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:The successful implementation of several quantum information and communication protocols requires distributing entangled pairs of quantum bits in a reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory effects for quantum information tasks are still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in an efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least a 12-fold improvement in the channel, or fiber length, for preserving the highly entangled initial polarization states of photons against dephasing.
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Nonlocal Memory assisted entanglement distribution in optical fibers
EPL (Europhysics Letters), 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:Successful implementation of several quantum information and communication protocols require distributing entangled pairs of quantum bits in reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory-effects for quantum information tasks is still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least 12-fold improvement in the channel, or fiber length, for preserving the highly-entangled initial polarization states of photons against dephasing.
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Nonlocal Memory effects allow perfect teleportation with mixed states
Scientific Reports, 2014Co-Authors: Elsi-mari Laine, Heinz-peter Breuer, Jyrki PiiloAbstract:One of the most striking consequences of quantum physics is quantum teleportation – the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of Nonlocal Memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that Memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks.
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Photonic realization of Nonlocal Memory effects and non-Markovian quantum probes
Scientific Reports, 2013Co-Authors: Bi-heng Liu, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Dong-yang Cao, Yun-feng Huang, Jyrki PiiloAbstract:The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. Recent developments in this field have increased our basic understanding on how non-Markovian effects influence the dynamics of an open quantum system, paving the way to exploit Memory effects for various quantum control tasks. Most often, the environment of an open system is thought to act as a sink for the system information. However, here we demonstrate experimentally that a photonic open system can exploit the information initially held by its environment. Correlations in the environmental degrees of freedom induce Nonlocal Memory effects where the bipartite open system displays, counterintuitively, local Markovian and global non-Markovian character. Our results also provide novel methods to protect and distribute entanglement, and to experimentally quantify correlations in photonic environments.
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Nonlocal Memory effects allow perfect teleportation with mixed states
arXiv: Quantum Physics, 2012Co-Authors: Elsi-mari Laine, Heinz-peter Breuer, Jyrki PiiloAbstract:We show that perfect quantum teleportation can be achieved with mixed photon polarization states when Nonlocal Memory effects influence the dynamics of the quantum system. The protocol is carried out with a pair of photons, whose initial maximally entangled state is destroyed by local decoherence prior to teleportation. It is demonstrated that the presence of strong Nonlocal Memory effects, which arise from initial correlations between the environments of the photons, allow to restore perfect teleportation. We further analyze how the amount of initial correlations within the environment affects the fidelity of the protocol, and find that for a moderate amount of correlations the fidelity exceeds the one of the previously known optimal teleportation protocol without Memory effects. Our results show that Memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks.
Heinz-peter Breuer - One of the best experts on this subject based on the ideXlab platform.
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Role of entanglement for Nonlocal Memory effects
Physical Review A, 2014Co-Authors: Steffen Wißmann, Heinz-peter BreuerAbstract:We present a scheme allowing to access the squeezing parameter of multimode fields by means of the dynamics of Nonlocal quantum probes. The model under consideration is composed of two two-level systems which are coupled locally to an environment consisting of Nonlocally correlated field modes given by two-mode Gaussian states. Introducing independently switchable interactions, one observes revivals of Nonlocal coherences of the two-qubit system which are unambiguously connected to the squeezing parameter of the Gaussian environmental states. Thus, the locally interacting two two-level systems represent a dynamical quantum probe for the squeezing in multimode fields. It is finally demonstrated that perfectly reviving Nonlocal coherences also persists for nonentangled correlated field modes and an explanation for this phenomenon is presented by connecting it to the correlation coefficient of the environmental coupling operators.
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entanglement distribution in optical fibers assisted by Nonlocal Memory effects
EPL, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:The successful implementation of several quantum information and communication protocols requires distributing entangled pairs of quantum bits in a reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory effects for quantum information tasks are still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in an efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least a 12-fold improvement in the channel, or fiber length, for preserving the highly entangled initial polarization states of photons against dephasing.
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Nonlocal Memory assisted entanglement distribution in optical fibers
EPL (Europhysics Letters), 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:Successful implementation of several quantum information and communication protocols require distributing entangled pairs of quantum bits in reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory-effects for quantum information tasks is still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least 12-fold improvement in the channel, or fiber length, for preserving the highly-entangled initial polarization states of photons against dephasing.
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Nonlocal Memory effects allow perfect teleportation with mixed states
Scientific Reports, 2014Co-Authors: Elsi-mari Laine, Heinz-peter Breuer, Jyrki PiiloAbstract:One of the most striking consequences of quantum physics is quantum teleportation – the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of Nonlocal Memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that Memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks.
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Memory Assisted Entanglement Distribution in Optical Fibers
Research in Optical Sciences, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Laine Elsi, Jyrki PiiloAbstract:we show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within optical fibers.
Guang-can Guo - One of the best experts on this subject based on the ideXlab platform.
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entanglement distribution in optical fibers assisted by Nonlocal Memory effects
EPL, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:The successful implementation of several quantum information and communication protocols requires distributing entangled pairs of quantum bits in a reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory effects for quantum information tasks are still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in an efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least a 12-fold improvement in the channel, or fiber length, for preserving the highly entangled initial polarization states of photons against dephasing.
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Nonlocal Memory assisted entanglement distribution in optical fibers
EPL (Europhysics Letters), 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Jyrki PiiloAbstract:Successful implementation of several quantum information and communication protocols require distributing entangled pairs of quantum bits in reliable manner. While there exists a substantial amount of recent theoretical and experimental activities dealing with non-Markovian quantum dynamics, experimental application and verification of the usefulness of Memory-effects for quantum information tasks is still missing. We combine these two aspects and show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within polarization-maintaining (PM) optical fibers. The introduced scheme is based on correlating the environments, i.e. frequencies of the polarization entangled photons, before their physical distribution. When comparing to the case without Nonlocal Memory effects, we demonstrate at least 12-fold improvement in the channel, or fiber length, for preserving the highly-entangled initial polarization states of photons against dephasing.
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Memory Assisted Entanglement Distribution in Optical Fibers
Research in Optical Sciences, 2014Co-Authors: Guo-yong Xiang, Zhibo Hou, Guang-can Guo, Heinz-peter Breuer, Laine Elsi, Jyrki PiiloAbstract:we show experimentally that a recently introduced concept of Nonlocal Memory effects allows to protect and distribute polarization entangled pairs of photons in efficient manner within optical fibers.
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Photonic realization of Nonlocal Memory effects and non-Markovian quantum probes
Scientific Reports, 2013Co-Authors: Bi-heng Liu, Guang-can Guo, Heinz-peter Breuer, Elsi-mari Laine, Dong-yang Cao, Yun-feng Huang, Jyrki PiiloAbstract:The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. Recent developments in this field have increased our basic understanding on how non-Markovian effects influence the dynamics of an open quantum system, paving the way to exploit Memory effects for various quantum control tasks. Most often, the environment of an open system is thought to act as a sink for the system information. However, here we demonstrate experimentally that a photonic open system can exploit the information initially held by its environment. Correlations in the environmental degrees of freedom induce Nonlocal Memory effects where the bipartite open system displays, counterintuitively, local Markovian and global non-Markovian character. Our results also provide novel methods to protect and distribute entanglement, and to experimentally quantify correlations in photonic environments.
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Nonlocal Memory effects in the dynamics of open quantum systems.
Physical review letters, 2012Co-Authors: Elsi-mari Laine, Heinz-peter Breuer, Jyrki Piilo, Guang-can GuoAbstract:We explore the possibility to generate Nonlocal dynamical maps of an open quantum system through local system-environment interactions. Employing a generic decoherence process induced by a local interaction Hamiltonian, we show that initial correlations in a composite environment can lead to Nonlocal open system dynamics which exhibit strong Memory effects, although the local dynamics is Markovian. In a model of two entangled photons interacting with two dephasing environments, we find a direct connection between the degree of Memory effects and the amount of correlation in the initial environmental state. The results demonstrate that, contrary to conventional wisdom, enlarging an open system can change the dynamics from Markovian to non-Markovian.
Hwan-sik Yoon - One of the best experts on this subject based on the ideXlab platform.
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A Hybrid Approach to Model Hysteretic Behavior of PZT Stack Actuators
Journal of Intelligent Material Systems and Structures, 2008Co-Authors: Jung-kyu Park, Gregory N. Washington, Hwan-sik YoonAbstract:In order to model the hysteretic behavior of piezoceramic actuators, a hybrid model is developed by combining the Preisach concepts with a neural network mapping function. Preisach concepts are utilized in producing a data set for generalization and calculating the final displacements for actuators having Nonlocal Memory. Although generalization is typically handled by interpolation functions in a traditional Preisach model, these functions can lead to significant errors unless there are sufficient data points around critical regions. In the hybrid model, the generalization of all first-order reversal curves is provided by a single neural network. Since the neural network is essentially a nonlinear mapping function, its functionality is implemented with a fewer number of variables than the Preisach model. In order to account for errors caused by frequency dependency and large input variations, an on-line training technique is also developed. Various comparisons between the outputs of the hybrid model and ...
