scholarly journals Entanglement transport and a nanophotonic interface for atoms in optical tweezers

Science ◽  
2021 ◽  
pp. eabi9917
Author(s):  
Tamara Ðorđević ◽  
Polnop Samutpraphoot ◽  
Paloma L. Ocola ◽  
Hannes Bernien ◽  
Brandon Grinkemeyer ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Free Space ◽  
Quantum Control ◽  
Entangled State ◽  
Science And Engineering ◽  
Entanglement Generation ◽  
Integrated Optical ◽  
Quantum Optical ◽  
Non Destructive ◽  
Full Quantum

The realization of an efficient quantum optical interface for multi-qubit systems is an outstanding challenge in science and engineering. Using two atoms in individually-controlled optical tweezers coupled to a nanofabricated photonic crystal cavity, we demonstrate entanglement generation, fast non-destructive readout, and full quantum control of atomic qubits. The entangled state is verified in free space after being transported away from the cavity by encoding the qubits into long-lived states and using dynamical decoupling. Our approach bridges quantum operations at an optical link and in free space by a coherent one-way transport, potentially enabling an integrated optical interface for atomic quantum processors.

scholarly journals Roll-to-Roll In-Line Implementation of Microwave Free-Space Non-Destructive Evaluation of Conductive Composite Thin Layer Materials

2021 ◽  
Vol 11 (1) ◽  
pp. 378
Author(s):  
Grigorios Koutsoukis ◽  
Ivan Alic ◽  
Antonios Vavouliotis ◽  
Ferry Kienberger ◽  
Kamel Haddadi
Keyword(s):  
Thin Film ◽  
Composite Materials ◽  
Free Space ◽  
Near Field ◽  
Line Production ◽  
Roll To Roll ◽  
Corrugated Horn ◽  
Evaluation Module ◽  
Microwave Nondestructive Testing ◽  
Non Destructive

A free-space microwave nondestructive testing and evaluation module is developed for the low-power, non-ionizing, contactless, and real-time characterization of doped composite thin-film materials in an industrial context. The instrumentation proposed is built up with a handled vector network analyzer interfaced with corrugated horn antennas to measure the near-field complex reflection S11 of planar prepreg composite materials in a roll-to-roll in-line production line. Dedicated modeling and calibrations routines are developed to extract the microwave conductivity from the measured microwave signal. Practical extraction of the radiofrequency (RF) conductivity of thin film prepreg composite materials doped with nano-powders is exemplary shown at the test frequency of 10 GHz.

scholarly journals Detection of Properties and Capacities of Quantum Channels

2017 ◽  
Vol 24 (04) ◽  
pp. 1740013 ◽  
Author(s):  
Chiara Macchiavello ◽  
Massimiliano F. Sacchi
Keyword(s):  
Entangled State ◽  
Quantum Channels ◽  
Quantum Process ◽  
Channel Output ◽  
Quantum Process Tomography ◽  
Channel Input ◽  
Process Tomography ◽  
Local Measurements ◽  
System States ◽  
Full Quantum

We review in a unified way a recently proposed method to detect properties of unknown quantum channels and lower bounds to quantum capacities, without resorting to full quantum process tomography. The method is based on the preparation of a fixed bipartite entangled state at the channel input or, equivalently, an ensemble of an overcomplete set of single-system states, along with few local measurements at the channel output.

scholarly journals Entanglement dynamics for static two-level atoms in cosmic string spacetime

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Pingyang He ◽  
Hongwei Yu ◽  
Jiawei Hu
Keyword(s):  
Cosmic String ◽  
Minkowski Spacetime ◽  
Scalar Fields ◽  
Entangled State ◽  
Entanglement Dynamics ◽  
Entanglement Generation ◽  
Maximally Entangled State ◽  
Interatomic Separation ◽  
Antisymmetric State ◽  
String Distance

Abstract We study the entanglement dynamics of two static atoms coupled with a bath of fluctuating scalar fields in vacuum in the cosmic string spacetime. Three different alignments of atoms, i.e. parallel, vertical, and symmetric alignments with respect to the cosmic string are considered. We focus on how entanglement degradation and generation are influenced by the cosmic string, and find that they are crucially dependent on the atom-string distance r, the interatomic separation L, and the parameter $$\nu $$ν that characterizes the nontrivial topology of the cosmic string. For two atoms initially in a maximally entangled state, the destroyed entanglement can be revived when the atoms are aligned vertically to the string, which cannot happen in the Minkowski spacetime. When the symmetrically aligned two-atom system is initially in the antisymmetric state, the lifetime of entanglement can be significantly enhanced as $$\nu $$ν increases. For two atoms which are initially in the excited state, when the interatomic separation is large compared to the transition wavelength, entanglement generation cannot happen in the Minkowski spacetime, while it can be achieved in the cosmic string spacetime when the position of the two atoms is appropriate with respect to the cosmic string and $$\nu $$ν is large enough.

Generation of four-photon polarization entangled states with cross-Kerr nonlinearity

2015 ◽  
Vol 13 (05) ◽  
pp. 1550024 ◽  
Author(s):  
Meiyu Wang ◽  
Fengli Yan
Keyword(s):  
Kerr Nonlinearity ◽  
Entangled States ◽  
Entangled State ◽  
Kerr Medium ◽  
Coherent Light ◽  
Photon Polarization ◽  
Beam Splitters ◽  
Ghz States ◽  
Different Types ◽  
Quantum Optical

We show how to prepare three different types of four-photon polarization entangled states among four modes. The scheme only use cross-Kerr medium, polarization beam splitters and X homodyne measurements on coherent light fields, which can be efficiently implemented in quantum optical laboratories. GHZ states and symmetric Dick states can be generated in deterministic way based on the scheme. With the possible availability of suitable strong Kerr nonlinearity, another type of entangled state called genuine four-photon entangled state can be realized as well.

A Daytime Free-Space Quantum-Optical Link using Atomic-Vapor Spectral Filters

2019 ◽  
Author(s):  
Christopher C. Evans ◽  
David N. Woolf ◽  
Justin M. Brown ◽  
Joel M. Hensley
Keyword(s):  
Free Space ◽  
Atomic Vapor ◽  
Optical Link ◽  
Spectral Filters ◽  
Quantum Optical
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