scholarly journals Enabling single qubit addressability in a molecular semiconductor comprising gold-supported organic radicals

2019 ◽  
Vol 10 (5) ◽  
pp. 1483-1491 ◽  
Author(s):  
Jake McGuire ◽  
Haralampos N. Miras ◽  
Emma Richards ◽  
Stephen Sproules
Keyword(s):  
Electron Spin ◽  
Organic Radicals ◽  
Organic Radical ◽  
Single Qubit ◽  
Spin Qubit ◽  
Molecular Semiconductor

An organic radical attached to gold represents an electrically addressable prototype electron spin qubit with an impressively long coherence lifetime.

scholarly journals Coherent control of a donor-molecule electron spin qubit in silicon

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lukas Fricke ◽  
Samuel J. Hile ◽  
Ludwik Kranz ◽  
Yousun Chung ◽  
Yu He ◽  
...  
Keyword(s):  
Electron Spin ◽  
Large Scale ◽  
Coherent Control ◽  
Atomic Plane ◽  
Local Area ◽  
Scanning Tunneling ◽  
Donor Molecule ◽  
Single Qubit ◽  
Spin Qubit ◽  
Qubit Gate

AbstractDonor spins in silicon provide a promising material platform for large scale quantum computing. Excellent electron spin coherence times of $${T}_{2}^{* }=268$$ T 2 * = 268  μs with fidelities of 99.9% have been demonstrated for isolated phosphorus donors in isotopically pure 28Si, where donors are local-area-implanted in a nanoscale MOS device. Despite robust single qubit gates, realising two-qubit exchange gates using this technique is challenging due to the statistical nature of the dopant implant and placement process. In parallel a precision scanning probe lithography route has been developed to place single donors and donor molecules on one atomic plane of silicon with high accuracy aligned to heavily phosphorus doped silicon in-plane gates. Recent results using this technique have demonstrated a fast (0.8 ns) two-qubit gate with two P donor molecules placed 13 nm apart in natSi. In this paper we demonstrate a single qubit gate with coherent oscillations of the electron spin on a P donor molecule in natSi patterned by scanning tunneling microscope (STM) lithography. The electron spin exhibits excellent coherence properties, with a $${T}_{2}$$ T 2 decoherence time of 298 ± 30 μs, and $${T}_{2}^{* }$$ T 2 * dephasing time of 295 ± 23 ns.

Engineering Electronic Structure to Protect Phase Memory in Molecular Qubits by Minimising Orbital Angular Momentum

2018 ◽  
Author(s):  
Ana Maria Ariciu ◽  
David H. Woen ◽  
Daniel N. Huh ◽  
Lydia Nodaraki ◽  
Andreas Kostopoulos ◽  
...  
Keyword(s):  
Electron Spin ◽  
Quantum Coherence ◽  
Quantum Information Processing ◽  
Pulse Sequences ◽  
Grover Algorithm ◽  
Ligand Shell ◽  
Information Strategies ◽  
Spin Qubit ◽  
Molecular Spin ◽  
The Impact

Using electron spins within molecules for quantum information processing (QIP) was first proposed by Leuenberger and Loss (1), who showed how the Grover algorithm could be mapped onto a Mn12 cage (2). Since then several groups have examined two-level (S = ½) molecular spin systems as possible qubits (3-12). There has also been a report of the implementation of the Grover algorithm in a four-level molecular qudit (13). A major challenge is to protect the spin qubit from noise that causes loss of phase information; strategies to minimize the impact of noise on qubits can be categorized as corrective, reductive, or protective. Corrective approaches allow noise and correct for its impact on the qubit using advanced microwave pulse sequences (3). Reductive approaches reduce the noise by minimising the number of nearby nuclear spins (7-11), and increasing the rigidity of molecules to minimise the effect of vibrations (which can cause a fluctuating magnetic field via spin-orbit coupling) (9,11); this is essentially engineering the ligand shell surrounding the electron spin. A protective approach would seek to make the qubit less sensitive to noise: an example of the protective approach is the use of clock transitions to render spin states immune to magnetic fields at first order (12). Here we present a further protective method that would complement reductive and corrective approaches to enhancing quantum coherence in molecular qubits. The target is a molecular spin qubit with an effective 2S ground state: we achieve this with a family of divalent rare-earth molecules that have negligible magnetic anisotropy such that the isotropic nature of the electron spin renders the qubit markedly less sensitive to magnetic noise, allowing coherent spin manipulations even at room temperature. If combined with the other strategies, we believe this could lead to molecular qubits with substantial advantages over competing qubit proposals.<br>

An Electron Spin Resonance Study of the Reaction of Nitrogen Dioxide with Metal Acetylacetonates

1973 ◽  
Vol 51 (24) ◽  
pp. 4072-4075 ◽  
Author(s):  
William H. Wolodarsky ◽  
Joshua Faniran ◽  
Jeffrey K. S. Wan
Keyword(s):  
Electron Spin Resonance ◽  
Nitrogen Dioxide ◽  
Electron Spin ◽  
Electron Spin Resonance Study ◽  
Organic Radical ◽  
Metal Acetylacetonates ◽  
Π Complex ◽  
Spin Resonance ◽  
Lower Oxidation ◽  
Spin Resonance Study

The reaction of nitrogen dioxide with several metal acetylacetonates was studied by electron spin resonance. Those metal complexes that have stable lower oxidation state, (i.e. Cu(II), Fe(III), Co(III), and VO(II)) react to form iminoxy radicals, while those metals not readily reduced (i.e. Zn(II), Cr(III), and Ce(III)) do not give iminoxy radicals. On the basis of the e.s.r. results, a simple mechanism was proposed to account for the formation of iminoxyacetylacetone radicals. A low temperature study of the e.s.r. spectra of the iminoxy-Cu(II)hexafluoroacetylacetonate suggested that a π-complex is formed between the organic radical and the Cu(II) compound.

scholarly journals Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot

2015 ◽  
Vol 11 (12) ◽  
pp. 1005-1008 ◽  
Author(s):  
Alexander Bechtold ◽  
Dominik Rauch ◽  
Fuxiang Li ◽  
Tobias Simmet ◽  
Per-Lennart Ardelt ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Electron Spin ◽  
Optically Active ◽  
Spin Qubit

scholarly journals Quantum non-demolition measurement of an electron spin qubit

2019 ◽  
Vol 14 (6) ◽  
pp. 555-560 ◽  
Author(s):  
Takashi Nakajima ◽  
Akito Noiri ◽  
Jun Yoneda ◽  
Matthieu R. Delbecq ◽  
Peter Stano ◽  
...  
Keyword(s):  
Electron Spin ◽  
Spin Qubit

CNOT gate operation on a photogenerated molecular electron spin-qubit pair

2020 ◽  
Vol 152 (1) ◽  
pp. 014503 ◽  
Author(s):  
Jordan N. Nelson ◽  
Jinyuan Zhang ◽  
Jiawang Zhou ◽  
Brandon K. Rugg ◽  
Matthew D. Krzyaniak ◽  
...  
Keyword(s):  
Electron Spin ◽  
Cnot Gate ◽  
Gate Operation ◽  
Molecular Electron ◽  
Spin Qubit
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