Impact of Spectators on a Two-Qubit Gate in a Tunable Coupling Superconducting Circuit

We show that an effective two-qubit gate can be obtained from the free evolution of three spins in a chain with nearest neighbor XY coupling, without local manipulations. This gate acts on the two remote spins and leaves the mediating spin unchanged. It can be used to perfectly transfer an arbitrary quantum state from the first spin to the last spin or to simultaneously communicate one classical bit in each direction. One ebit can be generated in half of the time for state transfer. For longer spin chains, we present methods to create or transfer entanglement between the two end spins in half of the time required for quantum state transfer, given tunable coupling strength and local magnetic field. We also examine imperfect state transfer through a homogeneous XY chain.

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Observation of macroscopic quantum coherence using new type of superconducting circuit

10.36471/jccm_january_2010_02 ◽

2010 ◽

Keyword(s):

Quantum Coherence ◽

Macroscopic Quantum ◽

Superconducting Circuit ◽

New Type ◽

Macroscopic Quantum Coherence

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Electric field control of radiative heat transfer in a superconducting circuit

Nature Communications ◽

10.1038/s41467-020-18163-8 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Olivier Maillet ◽

Diego Subero ◽

Joonas T. Peltonen ◽

Dmitry S. Golubev ◽

Jukka P. Pekola

Keyword(s):

Heat Transfer ◽

Electric Field ◽

Radiative Heat Transfer ◽

Radiative Heat ◽

Superconducting Circuit ◽

Field Control

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A phononic interface between a superconducting quantum processor and quantum networked spin memories

npj Quantum Information ◽

10.1038/s41534-021-00457-4 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Tomáš Neuman ◽

Matt Eichenfield ◽

Matthew E. Trusheim ◽

Lisa Hackett ◽

Prineha Narang ◽

...

Keyword(s):

Quantum State ◽

Piezoelectric Transducers ◽

High Fidelity ◽

Hybrid Architecture ◽

Quantum Networks ◽

Superconducting Circuit ◽

Artificial Atom ◽

Experimental Parameters ◽

Quantum Processor ◽

State Spin

AbstractWe introduce a method for high-fidelity quantum state transduction between a superconducting microwave qubit and the ground state spin system of a solid-state artificial atom, mediated via an acoustic bus connected by piezoelectric transducers. Applied to present-day experimental parameters for superconducting circuit qubits and diamond silicon-vacancy centers in an optimized phononic cavity, we estimate quantum state transduction with fidelity exceeding 99% at a MHz-scale bandwidth. By combining the complementary strengths of superconducting circuit quantum computing and artificial atoms, the hybrid architecture provides high-fidelity qubit gates with long-lived quantum memory, high-fidelity measurement, large qubit number, reconfigurable qubit connectivity, and high-fidelity state and gate teleportation through optical quantum networks.

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Atom‐Mediated Phonon Blockade and Controlled‐Z Gate in Superconducting Circuit System

Annalen der Physik ◽

10.1002/andp.202100039 ◽

2021 ◽

pp. 2100039

Author(s):

Chengsong Zhao ◽

Rui Peng ◽

Zhen Yang ◽

Shilei Chao ◽

Chong Li ◽

...

Keyword(s):

Superconducting Circuit

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Practical Security of RSA Against NTC-Architecture Quantum Computing Attacks

International Journal of Theoretical Physics ◽

10.1007/s10773-021-04789-x ◽

2021 ◽

Author(s):

Kai Li ◽

Qing-yu Cai

Keyword(s):

Quantum Computing ◽

Ion Trap ◽

Quantum Algorithms ◽

Coherence Time ◽

Quantum Computers ◽

Quantum Time ◽

Speed Up ◽

Key Length ◽

Concurrent Architecture ◽

Qubit Gate

AbstractQuantum algorithms can greatly speed up computation in solving some classical problems, while the computational power of quantum computers should also be restricted by laws of physics. Due to quantum time-energy uncertainty relation, there is a lower limit of the evolution time for a given quantum operation, and therefore the time complexity must be considered when the number of serial quantum operations is particularly large. When the key length is about at the level of KB (encryption and decryption can be completed in a few minutes by using standard programs), it will take at least 50-100 years for NTC (Neighbor-only, Two-qubit gate, Concurrent) architecture ion-trap quantum computers to execute Shor’s algorithm. For NTC architecture superconducting quantum computers with a code distance 27 for error-correcting, when the key length increased to 16 KB, the cracking time will also increase to 100 years that far exceeds the coherence time. This shows the robustness of the updated RSA against practical quantum computing attacks.

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