Towards a fullerene-based quantum computer

Abstract

Abstract. Molecular structures appear to be natural candidates for a quantum technology: individual atoms can support quantum superpositions for long periods, and such atoms can in principle be embedded in a permanent molecular scaffolding to form an array. This would be true nanotechnology, with dimensions of order of a nanometre. However, the challenges of realising such a vision are immense. One must identify a suitable elementary unit and demonstrate its merits for qubit storage and manipulation, including input / output. These units must then be formed into large arrays corresponding to an functional quantum architecture, including a mechanism for gate operations. Here we report our efforts, both experimental and theoretical, to create such a technology based on endohedral fullerenes or 'buckyballs'. We describe our successes with respect to these criteria, along with the obstacles we are currently facing and the questions that remain to be addressed.

Modeling spin interactions in carbon peapods using a hybrid density functional theory

“…9: ͑i͒ the charge arrangement within the carbon peapods, ͑ii͒ the electron-spin distribution, ͑iii͒ the coupling between spin qubits, and ͑iv͒ the nature of the spin interactions between fullerenes and nanotube. Density functional theory ͑DFT͒ calculations have been reported on several model systems, such as SWNTs containing C 60 , K x C 60 , Y@C 60 , C 82 , La@C 82 , La 2 @C 82 , and Sc 3 N@C 80 .…”

Quantum-information-processing architecture with endohedral fullerenes in a carbon nanotube

“…Additional challenges are associated with the peapod itself: depending on the system parameters, the distances between the molecules may vary, and the molecules may be arranged in zig-zag form rather than in a straight line [30]. In natural abundance, the 1% fraction of carbon nuclei that carry a nuclear spin ( 13 C) will contribute to the decoherence in the system.…”

Temporal resources for global quantum computing architectures

“…For the purpose of illustration, specific times were calculated for the case m = 0 and n = 1 (control unit and computational qubits adjacent to each other) under coupling strength J = 50 MHz ≈ 33 neV, which is a common order of magnitude for magnetic dipolar interactions in proposals such as fullerenebased electron spin quantum computers [20,21]. The results are shown in Table II.…”

“…The difference of five orders of magnitude in the optimal time required for the direct two-qubit gate execution between systems interacting under Ising and Förster coupling relies on the difference in their corresponding coupling intensities as taken from some representative systems such as fullerene-based electron spin quantum computers [20,21] and systems of quantum dots coupled via exchange interactions [23,26].…”