IBM demonstrates Shor’s algorithm using a 7-qubit quantum computer (published in Nature).

a research team from IBM and Stanford University reported in Nature that they had experimentally implemented Peter Shor’s quantum factoring algorithm using a 7-qubit quantum computer. The paper, titled “Experimental realization of Shor’s quantum factoring algorithm using nuclear magnetic resonance,” described the factoring of the number 15 into 3 × 5 using a liquid-state nuclear magnetic resonance (NMR) quantum processor. The experiment was carried out using seven nuclear spin qubits encoded in specially prepared molecules dissolved in solution. These qubits were manipulated using precisely timed radiofrequency pulses, allowing the researchers to implement the quantum Fourier transform and modular exponentiation steps required by Shor’s algorithm. The demonstration successfully produced the correct factors of 15, providing one of the earliest experimental validations of a full quantum algorithm rather than an isolated quantum gate operation. Shor’s algorithm, first proposed in 1994, showed that a sufficiently large and fault-tolerant quantum computer could factor large integers in polynomial time. This has direct implications for widely used public-key cryptographic systems such as RSA, whose security relies on the computational difficulty of factoring large composite numbers. The 2001 IBM-Stanford experiment did not threaten practical cryptography due to its small scale, but it demonstrated that the core logic of the algorithm could be physically realized in a laboratory setting. The results represented a transition from theoretical proposals of quantum computation to concrete experimental implementation of a nontrivial quantum algorithm. The publication in Nature on 15/12/2001 provided documented evidence that quantum information processing could execute structured algorithms involving entanglement and interference across multiple qubits. #QuantumComputing #ShorsAlgorithm #IBM #NatureJournal #QuantumInformation