Quantum information science

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Quantum mechanics
${\displaystyle i\hbar {\frac {d}{dt}}|\Psi \rangle ={\hat {H}}|\Psi \rangle }$ Schrödinger equation
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Experiments Bell's inequality CHSH inequality Davisson–Germer Double-slit Elitzur–Vaidman Franck–Hertz Leggett inequality Leggett–Garg inequality Mach–Zehnder Popper Quantum eraser Delayed-choice Schrödinger's cat Stern–Gerlach Wheeler's delayed-choice
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Quantum information science is a field that combines the principles of quantum mechanics with information theory to study the processing, analysis, and transmission of information. It covers both theoretical and experimental aspects of quantum physics, including the limits of what can be achieved with quantum information. The term quantum information theory is sometimes used, but it refers to the theoretical aspects of information processing and does not include experimental research.^[1]

At its core, quantum information science explores how information behaves when stored and manipulated using quantum systems. Unlike classical information, which is encoded in bits that can only be 0 or 1, quantum information uses quantum bits or qubits that can exist simultaneously in multiple states because of superposition. Additionally, entanglement—a uniquely quantum linkage between particles—enables correlations that have no classical counterpart.^[2][3][4] This new way of handling information opens up transformative possibilities in computation, communication, and sensing.^[5]

Quantum information science is inherently interdisciplinary, bringing together physics, computer science, mathematics, and engineering. It involves developing theoretical frameworks, designing quantum algorithms, constructing quantum hardware, and implementing quantum communication protocols.^[6]

Quantum teleportation, entanglement and the manufacturing of quantum computers depend on a comprehensive understanding of quantum physics and engineering. Google and IBM, among others, have invested significantly in quantum computer hardware research, leading to significant progress in manufacturing quantum computers since the 2010s. Currently, it is possible to build a quantum computer with over 100 qubits, but the error rates are high due to several factors including decoherence^[7], the lack of suitable hardware and materials for quantum computer manufacturing, which make it difficult to create a scalable quantum computer.^[8]

Quantum cryptography devices are now available for commercial use. The one time pad, a cipher used by spies during the Cold War, uses a sequence of random keys for encryption. These keys can be securely exchanged using quantum entangled particle pairs, as the principles of the no-cloning theorem and wave function collapse ensure the secure exchange of the random keys. The development of devices that can transmit quantum entangled particles is a significant scientific and engineering goal.^{[citation needed]}

Qiskit, Cirq and Q Sharp are popular quantum programming languages. Additional programming languages for quantum computers are needed, as well as a larger community of competent quantum programmers. To this end, additional learning resources are needed, since there are many fundamental differences in quantum programming which limits the number of skills that can be carried over from traditional programming.^[9]

Quantum algorithms and quantum complexity theory are two of the subjects in algorithms and computational complexity theory. In 1994, mathematician Peter Shor introduced a quantum algorithm for prime factorization^[10] that, with a quantum computer containing 4,000 logical qubits, could potentially break widely used ciphers like RSA and ECC, posing a major security threat. This led to increased investment in quantum computing research and the development of post-quantum cryptography^[11] to prepare for the fault-tolerant quantum computing (FTQC) era.^[12][13]

• Nielsen, Michael A.; Chuang, Isaac L. (June 2012). Quantum Computation and Quantum Information (10th anniversary ed.). Cambridge: Cambridge University Press. ISBN 9780511992773. OCLC 700706156.

• Quantiki – quantum information science portal and wiki.
• ERA-Pilot QIST WP1 European roadmap on Quantum Information Processing and Communication
• QIIC – Quantum Information, Imperial College London.
• QIP – Quantum Information Group, University of Leeds. The quantum information group at the University of Leeds is engaged in researching a wide spectrum of aspects of quantum information. This ranges from algorithms, quantum computation, to physical implementations of information processing and fundamental issues in quantum mechanics. Also contains some basic tutorials for the lay audience.
• mathQI Research Group on Mathematics and Quantum Information.
• CQIST Center for Quantum Information Science & Technology at the University of Southern California
• CQuIC Center for Quantum Information and Control, including theoretical and experimental groups from University of New Mexico, University of Arizona.
• CQT Centre for Quantum Technologies at the National University of Singapore
• CQC2T Centre for Quantum Computation and Communication Technology
• QST@LSU Quantum Science and Technologies Group at Louisiana State University
• QIST@TU Delft MSc programme Quantum Information Science & Technology at TU Delft.