scholarly journals Generation of multicomponent atomic Schrödinger cat states of up to 20 qubits

Science ◽  
2019 ◽  
Vol 365 (6453) ◽  
pp. 574-577 ◽  
Author(s):  
Chao Song ◽  
Kai Xu ◽  
Hekang Li ◽  
Yu-Ran Zhang ◽  
Xu Zhang ◽  
...  
Keyword(s):  
Quantum Information ◽  
Information Science ◽  
Quantum Information Processing ◽  
Ghz State ◽  
Many Body ◽  
Time Intervals ◽  
Fundamental Physics ◽  
Schrödinger Cat ◽  
Many Body Systems ◽  
Cat States

Multipartite entangled states are crucial for numerous applications in quantum information science. However, the generation and verification of multipartite entanglement on fully controllable and scalable quantum platforms remains an outstanding challenge. We report the deterministic generation of an 18-qubit Greenberger-Horne-Zeilinger (GHZ) state and multicomponent atomic Schrödinger cat states of up to 20 qubits on a quantum processor, which features 20 superconducting qubits, also referred to as artificial atoms, interconnected by a bus resonator. By engineering a one-axis twisting Hamiltonian, the system of qubits, once initialized, coherently evolves to multicomponent atomic Schrödinger cat states—that is, superpositions of atomic coherent states including the GHZ state—at specific time intervals as expected. Our approach on a solid-state platform should not only stimulate interest in exploring the fundamental physics of quantum many-body systems, but also enable the development of applications in practical quantum metrology and quantum information processing.

scholarly journals Generation and manipulation of Schrödinger cat states in Rydberg atom arrays

Science ◽  
2019 ◽  
Vol 365 (6453) ◽  
pp. 570-574 ◽  
Author(s):  
A. Omran ◽  
H. Levine ◽  
A. Keesling ◽  
G. Semeghini ◽  
T. T. Wang ◽  
...  
Keyword(s):  
Neutral Atom ◽  
Quantum Information Processing ◽  
Rydberg States ◽  
Rydberg Atom ◽  
Quantum Metrology ◽  
Many Body ◽  
Schrödinger Cat ◽  
Quantum Simulator ◽  
Cat States ◽  
The Many

Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging because such states are extremely fragile. Using a programmable quantum simulator based on neutral atom arrays with interactions mediated by Rydberg states, we demonstrate the creation of “Schrödinger cat” states of the Greenberger-Horne-Zeilinger (GHZ) type with up to 20 qubits. Our approach is based on engineering the energy spectrum and using optimal control of the many-body system. We further demonstrate entanglement manipulation by using GHZ states to distribute entanglement to distant sites in the array, establishing important ingredients for quantum information processing and quantum metrology.

scholarly journals Large array of Schrödinger cat states facilitated by an optical waveguide

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Wui Seng Leong ◽  
Mingjie Xin ◽  
Zilong Chen ◽  
Shijie Chai ◽  
Yu Wang ◽  
...  
Keyword(s):  
Quantum Information ◽  
Quantum Physics ◽  
Quantum Information Processing ◽  
Large Array ◽  
Hollow Core ◽  
Photonic Crystal Fibre ◽  
Wide Range ◽  
Schrödinger Cat ◽  
Cat States ◽  
Photon Interactions

Abstract Quantum engineering using photonic structures offer new capabilities for atom-photon interactions for quantum optics and atomic physics, which could eventually lead to integrated quantum devices. Despite the rapid progress in the variety of structures, coherent excitation of the motional states of atoms in a photonic waveguide using guided modes has yet to be demonstrated. Here, we use the waveguide mode of a hollow-core photonic crystal fibre to manipulate the mechanical Fock states of single atoms in a harmonic potential inside the fibre. We create a large array of Schrödinger cat states, a quintessential feature of quantum physics and a key element in quantum information processing and metrology, of approximately 15000 atoms along the fibre by entangling the electronic state with the coherent harmonic oscillator state of each individual atom. Our results provide a useful step for quantum information and simulation with a wide range of photonic waveguide systems.

scholarly journals Entanglement and Disordered-Enhanced Topological Phase in the Kitaev Chain

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 33 ◽  
Author(s):  
Liron Levy ◽  
Moshe Goldstein
Keyword(s):  
Phase Diagram ◽  
Information Theory ◽  
Quantum Information ◽  
Critical Point ◽  
Entanglement Entropy ◽  
Quantum Information Theory ◽  
Topological Phase ◽  
Many Body ◽  
Zero Modes ◽  
Many Body Systems

In recent years, tools from quantum information theory have become indispensable in characterizing many-body systems. In this work, we employ measures of entanglement to study the interplay between disorder and the topological phase in 1D systems of the Kitaev type, which can host Majorana end modes at their edges. We find that the entanglement entropy may actually increase as a result of disorder, and identify the origin of this behavior in the appearance of an infinite-disorder critical point. We also employ the entanglement spectrum to accurately determine the phase diagram of the system, and find that disorder may enhance the topological phase, and lead to the appearance of Majorana zero modes in systems whose clean version is trivial.

scholarly journals Coupling single emitters to quantum plasmonic circuits

Nanophotonics ◽  
2016 ◽  
Vol 5 (3) ◽  
pp. 483-495 ◽  
Author(s):  
Alexander Huck ◽  
Ulrik L. Andersen
Keyword(s):  
Quantum Information ◽  
Recent Progress ◽  
Quantum Information Processing ◽  
Single Photon ◽  
Strong Light ◽  
Fundamental Physics ◽  
Single Photon Emitters ◽  
Quantum Sensing ◽  
Matter Interaction ◽  
Light Matter Interaction

AbstractIn recent years, the controlled coupling of single-photon emitters to propagating surface plasmons has been intensely studied, which is fueled by the prospect of a giant photonic nonlinearity on a nanoscaled platform. In this article, we will review the recent progress on coupling single emitters to nanowires towards the construction of a new platform for strong light-matter interaction. The control over such a platform might open new doors for quantum information processing and quantum sensing at the nanoscale and for the study of fundamental physics in the ultrastrong coupling regime.

scholarly journals Dynamics of entanglement and non-classical correlation for four-qubit GHZ state

2015 ◽  
Vol 13 (06) ◽  
pp. 1550044 ◽  
Author(s):  
P. Espoukeh ◽  
R. Rahimi ◽  
S. Salimi ◽  
P. Pedram
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Discord ◽  
Quantum Information Processing ◽  
Ghz State ◽  
Classical Correlation ◽  
Qubit System ◽  
The Many ◽  
Sudden Transition

Many-qubit entanglement is crucial for quantum information processing although its exploitation is hindered by the detrimental effects of the environment surrounding the many-qubit system. It is thus of importance to study the dynamics of general multipartite non-classical correlation, including but not restricted to entanglement, under noise. We did this study for four-qubit Greenberger–Horne–Zeilinga (GHZ) state under most common noises in an experiment and found that non-classical correlation is more robust than entanglement except when it is imposed to dephasing channel. Quantum discord presents a sudden transition in its dynamics for Pauli-X and Pauli-Y noises as well as Bell-diagonal states interacting with dephasing reservoirs and it decays monotonically for Pauli-Z and isotropic noises.

CAN ENTANGLEMENT BE EXTRACTED FROM MANY BODY SYSTEMS?

2007 ◽  
Vol 05 (01n02) ◽  
pp. 125-130
Author(s):  
GABRIELE DE CHIARA ◽  
ČASLAV BRUKNER ◽  
G. MASSIMO PALMA ◽  
ROSARIO FAZIO ◽  
VLATKO VEDRAL
Keyword(s):  
Information Theory ◽  
Heat Capacity ◽  
Magnetic Susceptibility ◽  
Quantum Information ◽  
Spin Chain ◽  
Optical Lattice ◽  
Quantum Information Theory ◽  
Many Body ◽  
Thermodynamical Properties ◽  
Many Body Systems

Some thermodynamical properties of solids, such as heat capacity and magnetic susceptibility, have recently been shown to be linked to the amount of entanglement in a solid. Until now, however, it was not clear whether this entanglement can be used as a resource in quantum information theory. Here we show that this entanglement is physical, demonstrating the principles of its extraction from a typical spin chain by scattering two particles off the system. Moreover, we show how to simulate this process using present-day optical lattice technology.

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