scholarly journals Universal quantum computation using fractal symmetry-protected cluster phases

2018 ◽  
Vol 98 (2) ◽  
Author(s):  
Trithep Devakul ◽  
Dominic J. Williamson
Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 554
Author(s):  
Michael H. Freedman ◽  
Matthew B. Hastings ◽  
Modjtaba Shokrian Zini

We consider a model of quantum computation using qubits where it is possible to measure whether a given pair are in a singlet (total spin 0) or triplet (total spin 1) state. The physical motivation is that we can do these measurements in a way that is protected against revealing other information so long as all terms in the Hamiltonian are SU(2)-invariant. We conjecture that this model is equivalent to BQP. Towards this goal, we show: (1) this model is capable of universal quantum computation with polylogarithmic overhead if it is supplemented by single qubit X and Z gates. (2) Without any additional gates, it is at least as powerful as the weak model of "permutational quantum computation" of Jordan [14, 18]. (3) With postselection, the model is equivalent to PostBQP.


2011 ◽  
Vol 84 (2) ◽  
Author(s):  
Daniel J. Brod ◽  
Ernesto F. Galvão

2008 ◽  
Vol 8 (10) ◽  
pp. 977-985
Author(s):  
Z.-Y. Xu ◽  
M. Feng ◽  
W.-M. Zhang

We investigate the possibility to have electron-pairs in decoherence-free subspace (DFS), by means of the quantum-dot cellular automata (QCA) and single-spin rotations, to deterministically carry out a universal quantum computation with high-fidelity. We show that our QCA device with electrons tunneling in two dimensions is very suitable for DFS encoding, and argue that our design favors a scalable quantum computation robust to collective dephasing errors.


Nature ◽  
2017 ◽  
Vol 549 (7671) ◽  
pp. 172-179 ◽  
Author(s):  
Earl T. Campbell ◽  
Barbara M. Terhal ◽  
Christophe Vuillot

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