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MAGNETIC SYSTEMS AS CANDIDATES FOR QUANTUM COMPUTING HARDWARE.

Objective

Quantum storage and processing of information allow new computational tasks impossible with any conventional information technology. Such quantum computing (QC) requires a system of many quantum bits: qubits. This is an ASSESSMENT PROJECT to investigate a new QC candidate system, based on magnetic qubits. We propose to investigate both magnetic molecular clusters and dielectric nanometre-size single domain magnetic particles.

The main objectives are:
1) Understanding magnetic qubit decoherence, through comparison of resonance experiments with theory;
2) Measurement of a single magnetic qubit, using a micro-SQUID. Expected project results are data on and understanding of qubit quality factors, data on single qubit detection and supporting theory/modelling. Quantum storage and processing of information allow new computational tasks impossible with any conventional information technology. Such quantum computing (QC) requires a system of many quantum bits: qubits. This is an ASSESSMENT PROJECT to investigate a new QC candidate system, based on magnetic qubits. We propose to investigate both magnetic molecular clusters and dielectric nanometre-size single domain magnetic particles.

The main objectives are:
1) Understanding magnetic qubit decoherence, through comparison of resonance experiments with theory;
2) Measurement of a single magnetic qubit, using a micro-SQUID. Expected project results are data on and understanding of qubit quality factors, data on single qubit detection and supporting theory/modelling.

OBJECTIVES
We aim to investigate a new QC candidate system, based on magnetic qubits. If successful, we expect this investigation to lead to a longer term research effort to explore fully the possibility of magnetic QC and to initiate the development of magnetic QC technology. Specifically, this magnetic qubit consists of a nanometer-size magnetic particle (ferri- and antiferromagnetic particles and cluster sytems) and, in general dielectric, with a high quality factor Q for the ferromagnetic resonance. Such a high-Q system can sustain a quantum suprepositioin of the ground and first excited spin states and thus behave as qubit. While in the medium term we will operate in the mK regime, it is one of our goals to eventually operate also in the Kelvin regime.

DESCRIPTION OF WORK
1. Detection of the decoherence time in both molecular clusters and nanometer-size magnetic particles, and understanding the dissipation phenomena causing the de-coherence in these systems (e.g. the dependence on sample purity and nuclear spins). Our main aim here is to perform low temperature resonant experiments, 50 mK < T < 1.8 K, at frequencies between 1 MHz and 100 GHz. That is, we will focus our attention in phenomena having de-coherence time between 10 -6 and 10 -12 seconds. For the application as QC candidates, both the comparison of the de-coherence time with the time to perform gate-operations and the magnitude of the figure of merit Q are crucial;
2. Development of nano-techniques and technologies for the fabrication, handling, positioning and integration of a single magnetic qubit into a superconducting circuit containing a micro-SQUID. Most of the technological steps required for the integration of such devices (deposition of thin films of superconductors and oxides, electron beam and optical lithography, reactive ion beam etching, AFM manipulation and local oxidation, processing and characterization of magnetic dots) are already available in the proposers' laboratory.

Funding Scheme

ACM - Preparatory, accompanying and support measures

Coordinator

UNIVERSITAD DE BARCELONA
Address
Gran Via Corts Catalanes 585
08007 Barcelona
Spain

Participants (2)

CONSEJO SUPERIOR DE INVESTIGACIONES CIENTÍFICAS
Spain
Address
C(serrano, 117
Madrid
HEWLETT-PACKARD LIMITED
United Kingdom
Address
Cain Road
Bracknell