Quantum computing is a form of computation that uses quantum-mechanical effects, mainly superposition, entanglement, and interference, to process information in qubits instead of ordinary bits. It targets specific problem types, not everyday computing.
Why it matters
A bit is either 0 or 1. A qubit can be in a combination of both states until measured, and carefully designed algorithms use interference to make correct answers more likely. Quantum computers are not simply faster versions of laptops; they are expected to help with particular tasks such as simulating molecules, certain optimisation problems, and factoring large integers.
Current machines are limited by noise: qubits lose their state quickly and need error correction, which takes many physical qubits per reliable logical qubit. Shor's algorithm shows a large, error-corrected quantum computer could break RSA and elliptic-curve cryptography, which is why standards bodies such as NIST have published post-quantum cryptography standards.
Example
Searching an unsorted list of N items takes about N steps classically, while Grover's algorithm needs roughly the square root of N. That is a useful speed-up, but not the exponential one often implied in headlines.
Common misconceptions
- That a quantum computer tries every answer at once and picks the right one for free.
- That it will replace classical computers; it will likely be a specialised accelerator.
- That current encryption is already broken. Today's machines are far too small and noisy.
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यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.