Issues of practical realization of a quantum dot register for quantum computing

2000 ◽  
Vol 29 (5) ◽  
pp. 549-553 ◽  
Author(s):  
Alexander Balandin ◽  
Gaolong Jin ◽  
Kang L. Wang
Keyword(s):  
Quantum Computing ◽  
Quantum Dot ◽  
Practical Realization

scholarly journals Undecidable, Unrecognizable, and Quantum Computing

2020 ◽  
Vol 2 (3) ◽  
pp. 337-342
Author(s):  
Michael Siomau
Keyword(s):  
Quantum Computing ◽  
Turing Machine ◽  
Quantum Computer ◽  
Practical Realization ◽  
Real Numbers ◽  
Theoretical Limit ◽  
Halting Problem ◽  
The Real ◽  
Computing Model ◽  
Successful Design

Quantum computing allows us to solve some problems much faster than existing classical algorithms. Yet, the quantum computer has been believed to be no more powerful than the most general computing model—the Turing machine. Undecidable problems, such as the halting problem, and unrecognizable inputs, such as the real numbers, are beyond the theoretical limit of the Turing machine. I suggest a model for a quantum computer, which is less general than the Turing machine, but may solve the halting problem for any task programmable on it. Moreover, inputs unrecognizable by the Turing machine can be recognized by the model, thus breaking the theoretical limit for a computational task. A quantum computer is not just a successful design of the Turing machine as it is widely perceived now, but is a different, less general but more powerful model for computing, the practical realization of which may need different strategies than those in use now.

scholarly journals Spin-Based Quantum Dot Quantum Computing in Silicon

2004 ◽  
Vol 3 (1-5) ◽  
pp. 133-146 ◽  
Author(s):  
Mark A. Eriksson ◽  
Mark Friesen ◽  
Susan N. Coppersmith ◽  
Robert Joynt ◽  
Levente J. Klein ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Dot

All-optical quantum dot implementation for quantum computing

2002 ◽  
Vol 13 (2-4) ◽  
pp. 620-623 ◽  
Author(s):  
I D'Amico ◽  
E Biolatti ◽  
E Pazy ◽  
P Zanardi ◽  
F Rossi
Keyword(s):  
Quantum Computing ◽  
Quantum Dot ◽  
All Optical

scholarly journals A fault-tolerant addressable spin qubit in a natural silicon quantum dot

2016 ◽  
Vol 2 (8) ◽  
pp. e1600694 ◽  
Author(s):  
Kenta Takeda ◽  
Jun Kamioka ◽  
Tomohiro Otsuka ◽  
Jun Yoneda ◽  
Takashi Nakajima ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Dot ◽  
Fault Tolerant ◽  
Rabi Oscillation ◽  
Double Quantum ◽  
High Fidelity ◽  
Optimized Design ◽  
Industry Standard ◽  
Silicon Quantum Dot ◽  
Qubit Operation

Fault-tolerant quantum computing requires high-fidelity qubits. This has been achieved in various solid-state systems, including isotopically purified silicon, but is yet to be accomplished in industry-standard natural (unpurified) silicon, mainly as a result of the dephasing caused by residual nuclear spins. This high fidelity can be achieved by speeding up the qubit operation and/or prolonging the dephasing time, that is, increasing the Rabi oscillation quality factor Q (the Rabi oscillation decay time divided by the π rotation time). In isotopically purified silicon quantum dots, only the second approach has been used, leaving the qubit operation slow. We apply the first approach to demonstrate an addressable fault-tolerant qubit using a natural silicon double quantum dot with a micromagnet that is optimally designed for fast spin control. This optimized design allows access to Rabi frequencies up to 35 MHz, which is two orders of magnitude greater than that achieved in previous studies. We find the optimum Q = 140 in such high-frequency range at a Rabi frequency of 10 MHz. This leads to a qubit fidelity of 99.6% measured via randomized benchmarking, which is the highest reported for natural silicon qubits and comparable to that obtained in isotopically purified silicon quantum dot–based qubits. This result can inspire contributions to quantum computing from industrial communities.

scholarly journals Adiabatic quantum state transfer in a semiconductor quantum-dot spin chain

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yadav P. Kandel ◽  
Haifeng Qiao ◽  
Saeed Fallahi ◽  
Geoffrey C. Gardner ◽  
Michael J. Manfra ◽  
...  
Keyword(s):  
Quantum Computing ◽  
Quantum Dot ◽  
Quantum State ◽  
Information Transfer ◽  
Full Potential ◽  
Quantum State Transfer ◽  
Spin Qubits ◽  
Semiconductor Quantum Dot ◽  
State Transfer ◽  
Spin Singlet

AbstractSemiconductor quantum-dot spin qubits are a promising platform for quantum computation, because they are scalable and possess long coherence times. In order to realize this full potential, however, high-fidelity information transfer mechanisms are required for quantum error correction and efficient algorithms. Here, we present evidence of adiabatic quantum-state transfer in a chain of semiconductor quantum-dot electron spins. By adiabatically modifying exchange couplings, we transfer single- and two-spin states between distant electrons in less than 127 ns. We also show that this method can be cascaded for spin-state transfer in long spin chains. Based on simulations, we estimate that the probability to correctly transfer single-spin eigenstates and two-spin singlet states can exceed 0.95 for the experimental parameters studied here. In the future, state and process tomography will be required to verify the transfer of arbitrary single qubit states with a fidelity exceeding the classical bound. Adiabatic quantum-state transfer is robust to noise and pulse-timing errors. This method will be useful for initialization, state distribution, and readout in large spin-qubit arrays for gate-based quantum computing. It also opens up the possibility of universal adiabatic quantum computing in semiconductor quantum-dot spin qubits.

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