Mostly a very fancy fridge
The famous golden chandelier is almost entirely a cooling system; the quantum chip is smaller than a fingernail and hangs at the bottom, at about 0.01 degrees above absolute zero. Qubits are fragile (the tiniest heat or vibration "measures" them by accident and collapses their state (decoherence)) so cold, quiet isolation is the price of computation. The full story of what a quantum computer is and is not: start here.
How a quantum computation works: the six-step sequence
- Initialize qubits in a known state, commonly |0…0⟩.
- Apply gates that create superposition and encode the problem.
- Entangle qubits so the register can represent correlations among variables.
- Apply phase transformations and interference steps that amplify useful outcomes.
- Measure the qubits, producing a classical bit string.
- Repeat the circuit many times and use classical processing to estimate probabilities, energies, gradients, or candidate solutions.
Gates are reversible linear transformations. The Hadamard gate creates superposition, rotation gates change amplitudes and phase, and controlled gates like CNOT create entanglement. A circuit is a time-ordered sequence of these operations. The mechanism doing the real work is interference: amplitudes of wrong answers are arranged to cancel while right answers reinforce.
Why algorithms matter more than raw qubit count
A processor with many qubits is not automatically more useful. The algorithm must fit the hardware and beat a strong classical baseline at an economically relevant task. The metrics that actually describe a machine: