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Introduction and Background (maybe the lead section)

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Quantum information is an interdisciplinary field that involves Quantum Mechanics, Computer Science, Information Theory and Cryptography among other fields. Its main focus is in observing matter of the microscopic scale and extracting information from it. Observation in science is one of the most important ways of acquiring information and measurement is required in order to quantify the observation, making this crucial to the scientific method. However, it is impossible to make a perfect measurement in microscopic or quantum systems. (citation needed) While Quantum Mechanics deals with examining properties of matter at the microscopic level, Quantum information science focuses on extracting information from those properties. Cite error: The opening <ref> tag is malformed or has a bad name (see the help page).[1]

History (need to include pictures, tables and citations, close paraphrasing)

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Quantum mechanics was formulated by Schrodinger using wave mechanics and Heisenberg using matrix mechanics. Their formulations described the dynamics of microscopic systems but had several unsatisfactory aspects in describing measurement processes. Von Neumann [408] formulated quantum theory using operator algebra in a way that it described measurement as well as dynamics. What these studies emphasized the philosophical aspects of measurement rather than a quantitative approach to extracting information via measurements.[1]


In 1960s, Stratonovich [380] (link wiki), Helstrom [201] and Gordon [148, 149] proposed a formulation of optical communications using quantum mechanics. This was the first historical appearance of quantum information theory (link paper). They mainly studied error probabilities and channel capacities for communication (find and link paper). Later, Holevo [212,214] obtained an upper bound of communication speed in the transmission of a classical message via a quantum channel (link his two papers 214,212). He, along with others also studied problems in quantum estimations (link wiki article).


In the 1970s techniques for manipulating single quantum states were starting to get developped ( Atom trap, scanning tunneling microscope). Due to these developments, interest in manipulating single quantum states in an attempt of using it for computation and extracting information was developed.


In the 1980s, interest arose in whether it might be possible to use quantum effects to signal faster than light, an attempt of disproving Einstein's theory of relativity. If cloning and unknown quantum state were possible then Einstein's theory could be disproved. However, it turns out that quantum states could not, in general, be cloned. The no-cloning theorem is one of the earliest results of quantum information science.


Research in quantum information theory became stagnant in the 1980s. Around this time Bennett and Brassard[2] developed the BB48 quantum cryptographic protocol. Later Nagaoka furthered quantum estimation theory where he developed the asymptotic theory of quantum-state estimation and quantum information geometry (link to wikis)


In the 1900s, research in quantum information theory bloomed and important investigations were made, e.g quantum data compression, quantum teleportation, superdense coding, cryptographic protocols(B92)

  1. ^ a b Hayashi, Masahito (2017). Quantum Information Theory: Mathematical Foundation. Graduate Texts in Physics (2 ed.). Berlin Heidelberg: Springer-Verlag. ISBN 978-3-662-49723-4.
  2. ^ Bennett, Charles H.; Brassard, Gilles (2014-12). "Quantum cryptography: Public key distribution and coin tossing". Theoretical Computer Science. 560: 7–11. doi:10.1016/j.tcs.2014.05.025. ISSN 0304-3975. {{cite journal}}: Check date values in: |date= (help)