Deterministically Encoding Quantum Information Using 100-Photon Schrodinger Cat States

Science ◽  
2013 ◽  
Vol 342 (6158) ◽  
pp. 607-610 ◽  
Author(s):  
B. Vlastakis ◽  
G. Kirchmair ◽  
Z. Leghtas ◽  
S. E. Nigg ◽  
L. Frunzio ◽  
...  
Science ◽  
2019 ◽  
Vol 365 (6453) ◽  
pp. 574-577 ◽  
Author(s):  
Chao Song ◽  
Kai Xu ◽  
Hekang Li ◽  
Yu-Ran Zhang ◽  
Xu Zhang ◽  
...  

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.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Wui Seng Leong ◽  
Mingjie Xin ◽  
Zilong Chen ◽  
Shijie Chai ◽  
Yu Wang ◽  
...  

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.


2021 ◽  
Vol 17 (10) ◽  
pp. 1104-1108 ◽  
Author(s):  
M. Lewenstein ◽  
M. F. Ciappina ◽  
E. Pisanty ◽  
J. Rivera-Dean ◽  
P. Stammer ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Damian Kołaczek ◽  
Bartłomiej J. Spisak ◽  
Maciej Wołoszyn

AbstractThe coherent superposition of two well separated Gaussian wavepackets, with defects caused by their imperfect preparation, is considered within the phase-space approach based on the Wigner distribution function. This generic state is called the defective Schrödinger cat state due to this imperfection which significantly modifies the interference term. Propagation of this state in the phase space is described by the Moyal equation which is solved for the case of a dispersive medium with a Gaussian barrier in the above-barrier reflection regime. Formally, this regime constitutes conditions for backscattering diffraction phenomena. Dynamical quantumness and the degree of localization in the phase space of the considered state as a function of its imperfection are the subject of the performed analysis. The obtained results allow concluding that backscattering communication based on the defective Schrödinger cat states appears to be feasible with existing experimental capabilities.


Author(s):  
M. FORTUNATO ◽  
P. TOMBESI ◽  
D. VITALI ◽  
J. M. RAIMOND

Atoms ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 42 ◽  
Author(s):  
Wayne Huang ◽  
Herman Batelaan

The interference pattern in electron double-slit diffraction is a hallmark of quantum mechanics. A long-standing question for stochastic electrodynamics (SED) is whether or not it is capable of reproducing such effects, as interference is a manifestation of quantum coherence. In this study, we used excited harmonic oscillators to directly test this quantum feature in SED. We used two counter-propagating dichromatic laser pulses to promote a ground-state harmonic oscillator to a squeezed Schrödinger cat state. Upon recombination of the two well-separated wavepackets, an interference pattern emerges in the quantum probability distribution but is absent in the SED probability distribution. We thus give a counterexample that rejects SED as a valid alternative to quantum mechanics.


2000 ◽  
Vol 14 (07n08) ◽  
pp. 243-250
Author(s):  
XIAO-GUANG WANG ◽  
HONGCHEN FU

The superposition states of the λ-parameterized squeezed states are introduced and investigated. These states are intermediate states interpolating between the number and Schrödinger cat states and admit algebraic characterization in terms of su(1, 1) algebra. It is shown that these states exhibit remarkable nonclassical properties.


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