Answer: A [It causes qubits to spontaneously transition between energy levels, disrupting superposition states and leading to computational errors.]
Explanation: a: (Correct Option) Decoherence arises from unwanted interactions between qubits and their environment. This interaction disrupts the delicate superposition states of qubits, causing them to collapse into classical states. This process introduces errors into quantum computations as the qubits lose their quantum properties. The spontaneous transitions between energy levels are a direct consequence of these interactions.
b: While qubit connectivity and long-range entanglement are important considerations in quantum computer design, they are not the direct result of decoherence. Decoherence primarily affects the stability of quantum states rather than the physical connections between qubits.
c: Cryogenic cooling is necessary to mitigate the effects of thermal noise, which contributes to decoherence. However, the need for cryogenic cooling itself isn’t the direct impact of decoherence on qubit behavior. It’s a measure taken to counteract it.
d: While decoherence can affect the fidelity of quantum gates, it doesn’t fundamentally restrict the types of gates that can be implemented. The limitation comes from the difficulty in maintaining coherence long enough to execute complex gate sequences accurately.