scholarly journals Long-range qubit entanglement via rolled-up zero-index waveguide

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ibrahim Issah ◽  
Mohsin Habib ◽  
Humeyra Caglayan
Keyword(s):  
Long Range ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Effective Interaction ◽  
Cost Effective ◽  
Entangled State ◽  
Entanglement Measure ◽  
Novel Structure ◽  
Fdtd Simulations ◽  
Zero Index

Abstract Preservation of an entangled state in a quantum system is one of the major goals in quantum technological applications. However, entanglement can be quickly lost into dissipation when the effective interaction among the qubits becomes smaller compared to the noise-injection from the environment. Thus, a medium that can sustain the entanglement of distantly spaced qubits is essential for practical implementations. This work introduces the fabrication of a rolled-up zero-index waveguide which can serve as a unique reservoir for the long-range qubit–qubit entanglement. We also present the numerical evaluation of the concurrence (entanglement measure) via Ansys Lumerical FDTD simulations using the parameters determined experimentally. The calculations demonstrate the feasibility and supremacy of the experimental method. We develop and fabricate this novel structure using cost-effective self-rolling techniques. The results of this study redefine the range of light-matter interactions and show the potential of the rolled-up zero-index waveguides for various classical and quantum applications such as quantum communication, quantum information processing, and superradiance.

scholarly journals Optimal teleportation via noisy quantum channels without additional qubit resources

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Dong-Gil Im ◽  
Chung-Hyun Lee ◽  
Yosep Kim ◽  
Hyunchul Nha ◽  
M. S. Kim ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Teleportation ◽  
Quantum Communication ◽  
Quantum Noise ◽  
Single Copy ◽  
Entangled State ◽  
Quantum Network ◽  
Quantum Channels ◽  
Maximally Entangled State ◽  
Near Term

AbstractQuantum teleportation exemplifies how the transmission of quantum information starkly differs from that of classical information and serves as a key protocol for quantum communication and quantum computing. While an ideal teleportation protocol requires noiseless quantum channels to share a pure maximally entangled state, the reality is that shared entanglement is often severely degraded due to various decoherence mechanisms. Although the quantum noise induced by the decoherence is indeed a major obstacle to realizing a near-term quantum network or processor with a limited number of qubits, the methodologies considered thus far to address this issue are resource-intensive. Here, we demonstrate a protocol that allows optimal quantum teleportation via noisy quantum channels without additional qubit resources. By analyzing teleportation in the framework of generalized quantum measurement, we optimize the teleportation protocol for noisy quantum channels. In particular, we experimentally demonstrate that our protocol enables to teleport an unknown qubit even via a single copy of an entangled state under strong decoherence that would otherwise preclude any quantum operation. Our work provides a useful methodology for practically coping with decoherence with a limited number of qubits and paves the way for realizing noisy intermediate-scale quantum computing and quantum communication.

On the classical character of control fields in quantum information processing

2002 ◽  
Vol 2 (1) ◽  
pp. 1-13
Author(s):  
S.J. van Enk ◽  
H.J. Kimble
Keyword(s):  
Quantum Computing ◽  
Information Processing ◽  
Quantum Information ◽  
Laser Beam ◽  
Quantum State ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Laser Fields ◽  
Undesirable Property

Control fields in quantum information processing are almost by definition assumed to be classical. In reality, however, when such a field is used to manipulate the quantum state of qubits, the qubits always become slightly entangled with the field. For quantum information processing this is an undesirable property, as it precludes perfect quantum computing and quantum communication. Here we consider the interaction of atomic qubits with laser fields and quantify atom-field entanglement in various cases of interest. We find that the entanglement decreases with the average number of photons \bar{n} in a laser beam as $E\propto\log_2 \bar{n}/\bar{n}$ for $\bar{n}\rightarrow\infty$.

ERROR-REJECTING BENNETT–BRASSARD–MERMIN QUANTUM KEY DISTRIBUTION PROTOCOL BASED ON LINEAR OPTICS OVER A COLLECTIVE-NOISE CHANNEL

2010 ◽  
Vol 08 (07) ◽  
pp. 1141-1151 ◽  
Author(s):  
XI-HAN LI ◽  
XIAO-JIAO DUAN ◽  
FU-GUO DENG ◽  
HONG-YU ZHOU
Keyword(s):  
Quantum Entanglement ◽  
Quantum Key Distribution ◽  
Quantum Information Processing ◽  
Key Distribution ◽  
Entangled State ◽  
Collective Noise ◽  
Linear Optics ◽  
Entanglement Purification ◽  
Measurement Results ◽  
Entangled Quantum States

Quantum entanglement is an important element of quantum information processing. Sharing entangled quantum states between two remote parties is a precondition of most quantum communication schemes. We will show that the protocol proposed by Yamamoto et al. (Phys. Rev. Lett.95 (2005) 040503) for transmitting single quantum qubit against collective noise with linear optics is also suitable for distributing the components of entanglements with some modifications. An additional qubit is introduced to reduce the effect of collective noise, and the receiver can take advantage of the time discrimination and the measurement results of the assistant qubit to reconstruct a pure entanglement with the sender. Although the scheme succeeds probabilistically, the fidelity of the entangled state is almost unity in principle. The resource used in our protocol to get a pure entangled state is finite, which establishes entanglement more easily in practice than quantum entanglement purification. Also, we discuss its application in quantum key distribution over a collective channel in detail.

Entanglement created in three-quantum dot system coupled to plasmonic waveguide

2020 ◽  
Vol 34 (20) ◽  
pp. 2050190
Author(s):  
Ju-Song Ryom ◽  
Myong-Chol Ko ◽  
Nam-Chol Kim ◽  
Gwang-Il Kim ◽  
Song-Il Choe ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Interparticle Distance ◽  
Plasmonic Waveguide ◽  
Quantum Mechanical ◽  
Bipartite Entanglement ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach ◽  
Better Than

We investigate the entanglement properties of three-quantum dot (QD) system coupled to surface plasmonic waveguide by means of the concurrence with fully quantum-mechanical approach. High bipartite entanglement of three QDs could be achieved by adjusting the interparticle distance of the QDs, the detuning and the QD-waveguide coupling strength. We show that the bipartite entanglement of three-QD system is higher and its switching effect is better than the case of two-QD system. The discussed system with three QDs provides us rich way to realize the quantum entanglement used in the quantum information processing such as quantum computation and quantum communication.

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