Quantum Annealer and Quantum Gate Based Computers

Here is my day 2 log on 30 Days Quantum Learn challenge by QuantumComputingIndia

Quantum Annealer and Universal Gate Based Quantum Computer:

Quantum Computers can solve a certain set of problems faster by exploiting quantum principles( Superposition and Entanglement)

Quantum Annealer are used for optimizing problems like scheduling problems , optimal travel route problems , Gaming problems etc.,

Dwave machines are examples of quantum annealer. These are built using superconducting Qubits.

QUBO and ISO are the two components in the annealer which is responsible to convert the problem into graph problem and then it will be mapped to the structure of teh quantum chip.

in thermal physics , annealer are like heating a metal and gradually cool it down to the low energy state.

Universal Gate Based Quantum Computers?

Basic circuit operations and putting the gates and solve algorithms

Quantum gates are reversible.

Unary Qubit — hadamard — used for superposition of the one qubit

Binary Qubit — CNOT → bit flips the target
Three Gate — ToffoliGate , CCNOT Gates

Is a quantum annealer is actually a quantum computer?

Annealer can also use entanglement and superposition , and hence its a quantum computer but it can efficiently implement only few algorithms.

Divincenzo criteria for physical implementation of a quantum computer:

1) Scalable and physical system for well characterized qubits
2) Intialize state of qubits
3) Long coherence times(amount of time the qunatum information to be stored) much longer than gate operation times
4) Approximate the unitary transformation which preserves the inner product
5) Qubit measurement capability.

Quantum Volume is the metric to measure the performance .

Decoherence — losing the quantum information from the system

HoneyWell H1 has higher quantum volume than IBM 27 Qubits.

Reference:Quantum Annealer Vs Gate Based Quantum Computer Youtube video by Anastasia Marchenkova.