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Perturbative algorithm for rotational decoherence
, Article Physical Review A ; Volume 103, Issue 3 , 2021 ; 24699926 (ISSN) ; Naeij, H.R ; Bassi, A ; Sharif University of Technology
American Physical Society
2021
Abstract
Recent advances in levitated optomechanics provide new perspectives for the use of rotational degrees of freedom for the development of quantum technologies as well as for testing fundamental physics. As for the translational case, their use, especially in the quantum regime, is limited by environmental noises, the characterization of which is fundamental in order to assess, control, and minimize their effect, in particular decoherence. Here, we present a general perturbative approach to compute decoherence for a quantum system in a superposition of its rotational degrees of freedom. The specific cases of the dipole-dipole and quadrupole-quadrupole interactions are solved explicitly, and we...
Rydberg noisy dressing and applications in making soliton molecules and droplet quasicrystals
, Article Physical Review Research ; Volume 3, Issue 3 , 2021 ; 26431564 (ISSN) ; Sharif University of Technology
American Physical Society
2021
Abstract
The current advances in the field of ultracold atoms and atomic traps recall new controllable long-range interactions. These interactions are expected to extend the range of realizable quantum algorithms as well as provide new control mechanisms for the new types of quantum matters. This Letter presents special interatomic interactions between Rydberg-dressed atoms by manipulating the lasers' linewidth. The proposed interaction features a hybrid spatial profile containing plateaus and Gaussian peaks. Combined with dynamic control over the sign and strength of individual interaction elements, the Rydberg noisy-dressing (RnD) scheme provides a valuable interaction toolbox for quantum...
Novel technique for robust optimal algorithmic cooling
, Article Physical Review Letters ; Volume 122, Issue 22 , 2019 ; 00319007 (ISSN) ; Kieferová, M ; Mosca, M ; Sharif University of Technology
American Physical Society
2019
Abstract
Heat-bath algorithmic cooling provides algorithmic ways to improve the purity of quantum states. These techniques are complex iterative processes that change from each iteration to the next and this poses a significant challenge to implementing these algorithms. Here, we introduce a new technique that on a fundamental level, shows that it is possible to do algorithmic cooling and even reach the cooling limit without any knowledge of the state and using only a single fixed operation, and on a practical level, presents a more feasible and robust alternative for implementing heat-bath algorithmic cooling. We also show that our new technique converges to the asymptotic state of heat-bath...
Finding semi-optimal measurements for entanglement detection using autoencoder neural networks
, Article Quantum Science and Technology ; Volume 5, Issue 4 , 16 July , 2020 ; Mostaan, M. R ; Raeisi, S ; Sharif University of Technology
IOP Publishing Ltd
2020
Abstract
Entanglement is one of the key resources of quantum information science which makes identification of entangled states essential to a wide range of quantum technologies and phenomena. This problem is however both computationally and experimentally challenging. Here we use autoencoder neural networks to find semi-optimal set of incomplete measurements that are most informative for the detection of entangled states. We show that it is possible to find high-performance entanglement detectors with as few as three measurements. Also, with the complete information of the state, we develop a neural network that can identify all two-qubits entangled states almost perfectly. This result paves the way...
Quantum CDMA communication systems
, Article IEEE Transactions on Information Theory ; Volume 67, Issue 8 , 2021 , Pages 5526-5547 ; 00189448 (ISSN) ; Salehi, J. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Barcoding photons, atoms, and any quantum states can provide a host of functionalities that could benefit future quantum communication systems and networks beyond today's imagination. As a significant application of barcoding photons, we introduce code division multiple-access (CDMA) communication systems for various applications. In this context, we introduce and discuss the fundamental principles of a novel quantum CDMA (QCDMA) technique based on spectrally encoding and decoding of continuous-mode quantum light pulses. In particular, we present the mathematical models of various QCDMA modules that are fundamental in describing an ideal and typical QCDMA system, such as quantum signal...