Coupled quantum dots as quantum gates

Physical Review B - Condensed Matter and Materials Physics

Volumn 59, Issue 3, 1999, Pages 2070-2078

  DiVincenzo, DavidP ^b   Loss, Daniel ^a  

^a UNIVERSITY OF BASEL   (Switzerland)

^b IBM T J WATSON RESEARCH CENTER   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000818466     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.59.2070     Document Type: Article

References (49)

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48. If during the change of (Formula presented) the total spin remains conserved, no transitions between the instantaneous singlet and triplet eigenstates can be induced during the switching. Thus, the singlet and triplet states evolve independently of each other, and the condition on adiabatic switching involves Δε (instead of (Formula presented)), i.e., we only need to require that (Formula presented) which would be less restrictive. Also, only (Formula presented) and not (Formula presented) itself is needed for the gate operation. Therefore, the adiabaticity criterion given in the text, while being sufficient, need not be really necessary. However, the complete analysis of the time-dependent problem in terms of variational wave functions is beyond the scope of the present paper and will be addressed elsewhere.
49. We note that it is sufficient to have single-qubit rotations about any two orthogonal axes. A preferable choice here are two orthogonal in-plane axes because magnetic fields (Formula presented) parallel to the 2DEG do not affect the exchange coupling (Formula presented) (assuming that we can exclude subband mixing induced by a sufficiently strong (Formula presented)).