16-qubit IBM universal quantum computer can be fully entangled

Abstract

Entanglement is an important evidence that a quantum device can potentially solve problems intractable for classical computers. In this paper, we prepare connected graph states involving 8 to 16 qubits on ibmqx5, a 16-qubit superconducting quantum processor accessible via IBM cloud, using low-depth circuits. We demonstrate that the prepared state is fully entangled, i.e. the state is inseparable with respect to any fixed partition.

Phononic-waveguide-assisted steady-state entanglement of silicon-vacancy centers

“…Multiparticle entanglement has attracted great attention for its diverse applications in quantum metrology and quantum computing [1][2][3][4][5][6][7][8][9][10]. Efforts along this direction have lead to a plenty of proposals for generating entangled states with particles as many as possible [11][12][13], such as spin squeezing states [14][15][16] and GHZ states [17][18][19][20]. So far, multiparticle entanglement has been realized involving up to 20 qubits in trapped-ion systems [21], and 12 qubits in superconducting circuits [22].…”

Large-alphabet quantum key distribution using spatially encoded light

“…Human society relies increasingly on the availability of affordable and high-speed communication, which fosters the need of high key-rate generating cryptography. Recent progress in the development of quantum computers [1][2][3][4][5] threatens the widely used cryptographic methods, which rely on computational assumptions [6,7]. A possible solution is quantum key distribution (QKD) of which the security is only based on quantum physics and not on any computational assumption.…”

Universal DV-CV interaction mechanism for deterministic generation of entangled hybridity

“…Again, as in the cases considered above, the CV states consist of either exclusively even (|Ψ (2 ) ⟩, |Ψ (2 +1) ⟩ ) or odd (|Ψ (2 ) ⟩, |Ψ (2 +1) ⟩ ) Fock states regardless of the parameter values 2 2 +1 ⁄ , 2 2 +1 ⁄ and 2 2 +1 ⁄ . Note also that states (45-48) include additional terms.…”

“…where we introduce the following normalization factors: (2 ) is for the state (45), (2 ) is for the state (46), (2 +1) is for the state (47) and (2 +1) is for the state (48). The analytical expressions for the normalization factors are rather complex (therefore, they are not presented here) since the states | + ⟩ (| − ⟩), |1, ⟩ (|1, ⟩), |2, ⟩ (|2, ⟩) are not orthogonal to each other.…”

“…Many physical systems, involving photons, atoms, ions and superconducting platforms, are used for construction of a quantum computer [1] and quantum processors with tens of qubits have been demonstrated [2,3]. In general, despite the wide variety of the physical systems, quantum information processing (QIP) comes in two different depending on the degree of observable used to extract information from quantum state.…”