Quantum computer
AssigneeHitachi, Ltd.
InventorsDavid Arfon Williams, Paul Cain
Life of this patent
Estimating the term…
Abstract
A quantum computer comprises a trench-isolated channel region formed in a boron-doped silicon germanium layer which has narrow channel regions which form tunnel barriers and wide channel regions which define first and second quantum dots. Tunnelling between the first and second quantum dots is controlled by a side gate and/or a surface gate. The quantum states used to represent a qubit may be defined as |an excess hole on the first quantum dot> and |an excess hole on the second quantum dot>. A Hadamard Transformation UH of an initial state may be effected by application of a pulse to the side or surface gate. The first and second tunnel quantum dots are of unequal size which helps decouple the quantum computer from the environment.
Claims38
A quantum computer for transforming a first state into a second state comprising:
- a first quantum dot;
- a second quantum dot;
- said first and second quantum dots being spaced apart and arranged so as to define first and second basis states of a quantum bit;
- gate electrodes for preparing said first state as a superposition of said first and second basis states;
- and
- gate electrodes for controlling coupling between said first and second quantum dots so as to transform said first state into said second state.
A quantum computer for transforming a first state into a second state comprising:
- an array of elements, each element of the array comprising:
- a first quantum dot;
- a second quantum dot;
- said first and second quantum dots being spaced apart and arranged so as to define first and second basis states of a quantum bit
- gate electrodes for preparing a quantum bit state as a superposition of said first and second basis states;
- said elements being arranged so as to cause entanglement of the quantum bits of said elements of said array;
- gate electrodes for preparing said first state as an entangled superposition of quantum bit states and
- gate electrodes for controlling coupling between first and second quantum dots of at least one element so as to transform said first state into said second state.
A method of operating a quantum computer comprising a first quantum dot, a second quantum dot, said first and second quantum dots being spaced apart and arranged so as to define first and second basis states, the method comprising:
- preparing a first state as a superposition of said first and second basis states and
- controlling coupling between said first and second quantum dots so as to transform said first state into a second state.
A quantum computer for transforming a first state into a second state comprising:
- a structure for defining a first quantum dot;
- a structure for defining a second quantum dot;
- said structures for defining said first and second quantum dots being spaced apart and arranged so as to define first and second basis states of a quantum bit;
- gate electrodes for preparing said first state as a superposition of said first and second basis states;
- and
- gate electrodes for controlling coupling between said first and second quantum dots so as to transform said first state into said second state.
An electronic device comprising:
- a channel for charge carriers;
- a source for providing charge carriers to said channel with a first range of charge carrier energy,
- said channel comprising:
- a first quantum dot with a first set of energy levels;
- a second quantum dot with a second set of energy levels having different level spacing from the first set;
- wherein the first range of charge carrier energy is greater than the spacing between a pair of adjacent energy levels of the first quantum dot and that charge carrier transport through the device only takes place through a one of the first set of energy levels and a one of the second set of energy levels which are energetically aligned.
Dependencies are inferred from the claim text.