23-01-2020 дата публикации
Номер: US20200027017A1
Принадлежит:
An always-on, exchange-only (AEON) qubit is comprised of three two-level systems (e.g., semiconductor quantum dot or other spin encoded qubit) and can be operated at a “sweet spot” during both single qubit and two-qubit gate operations. The “sweet spot” operation is immune to variations in noise with respect to nontrivial detuning parameters defining the AEON. By operating at the “sweet spot,” both single and two-qubit gate operations can be performed using only exchange pulses (e.g., DC voltage pulses applied to tunneling gates). 1. A method comprising:performing a single qubit gate operation on a three-spin qubit or a two-qubit gate operation on adjacent three-spin qubits,{'sub': 1', '3, 'wherein each qubit has first through third two-level systems having respective local potentials εthrough ε,'}wherein each qubit is characterized by a pair of non-trivial detuning parameters representing energy differences between respective energy levels of the two-level systems of the qubit, [{'sup': '−3', 'local potentials of the two-level systems of each qubit are controlled such that derivatives of a respective frequency of the qubit with respect to each detuning parameter are within 10of zero, and'}, 'tunnel couplings between adjacent two-level systems of each qubit are controlled to be non-zero., 'wherein in performing the single qubit gate operation or the two-qubit gate operation3. The method of claim 2 , wherein the local potentials are controlled such that:{'br': None, 'i': Ũ', '+Ũ′', '−Ũ', '+Ũ, 'sub': 1', '2', '2', '3', 'av, 'ε=¼(−)±0.1 U, and \u2003\u2003(1)'}{'br': None, 'sub': M', '1', '2', '2', '3', 'av, 'i': Ũ', '−Ũ′', '−Ũ', '+Ũ, 'ε=¼()±0.1 U, \u2003\u2003(2)'}{'sub': 'i', 'wherein Ũrepresents a change in Coulomb interaction energy when an i-th two-level system is doubly occupied by tunneling of an electron from an adjacent two-level system,'}{'sub': av', '1', '2', '2', '3, 'wherein Uis the average of value of Ũ, Ũ, Ũ′, and Ũ,'}{'sub': '2', 'wherein Ũ′corresponds ...
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