Abstract
Quantum computing algorithms require that the quantum register be initially present in a superposition state. To achieve this, we consider the practical problem of creating a coherent superposition state of several qubits. We show that the constraints of quantum statistics require that the entropy of the system be brought down when several independent qubits are assembled together. In particular, we have: (i) not all initial states are realizable as pure states; (ii) the temperature of the system must be reduced. These factors, in addition to decoherence and sensitivity to errors, must be considered in the implementation of quantum computers.
Similar content being viewed by others
References
D Deutsch, Proc. R. Soc. London A425, 73 (1989)
P W Shor, SIAM J. Comput. 26, 1474 (1997)
L K Grover, Phys. Rev. Lett. 79, 325 (1997)
A Ekert and R Jozsa, Rev. Mod. Phys. 68, 733 (1996)
S Bose et al, Philos. Trans. R. Soc. London A356, 1823 (1998)
N Gershenfeld and I L Chuang, Science 275, 350 (1997)
D G Cory et al, Proc. Natl. Acad. Sci. USA 94, 1634 (1997)
J A Jones et al, Nature 403, 869 (2000)
L M K Vandersypen et al, Phys. Rev. Lett. 85, 5452 (2000)
S L Braunstein et al, Phys. Rev. Lett. 83, 1054 (1999)
S Kak, Found. Phys. 29, 267 (1999)
S Kak, Info. Sci. 128, 149 (2000)
A K Pati and S L Braunstein, Nature (London) 400, 164 (2000)
D Jonathan and M B Plenio, Phys. Rev. Lett. 83, 3566 (1999)
A Peres, Quantum theory: Concepts and methods (Kluwer Academic, Dordrecht, 1995)
S Kak, Found. Phys. 26, 1375 (1996)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kak, S. Statistical constraints on state preparation for a quantum computer. Pramana - J Phys 57, 683–687 (2001). https://doi.org/10.1007/s12043-001-0019-7
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/s12043-001-0019-7