Estimate logical qubits from physical qubits.
Von Neumann entropy.
Estimate the number of logical qubits required for fault-tolerant quantum computation, given the physical qubit error rate. Plan your quantum resources.
Feasibility check for quantum circuits.
Calculate T1 and T2 decoherence times to estimate operation limits imposed by quantum decoherence. Optimize quantum algorithm design.
Qubits needed to factor N.
Quantum advantage iterations.
Quantum Key Distribution rate estimate.
Probability of tunneling through a barrier.
Probabilities from amplitudes.