Skip to main content

Looking for Pairs that Hard to Separate: A Quantum Approach

  • Conference paper
  • First Online:

Part of the book series: Lecture Notes in Computer Science ((LNTCS,volume 9705))

Abstract

Determining the minimum number of states required by a deterministic finite automaton to separate a given pair of different words (to accept one word and to reject the other) is an important challenge. In this paper, we ask the same question for quantum finite automata (QFAs). We classify such pairs as easy and hard ones. We show that 2-state QFAs with real amplitudes can separate any easy pair with zero-error but cannot separate some hard pairs even in nondeterministic acceptance mode. When using complex amplitudes, 2-state QFAs can separate any pair in nondeterministic acceptance mode, and here we conjecture that they can separate any pair also with zero-error. Then, we focus on (a more general problem) separating a pair of two disjoint finite set of words. We show that QFAs can separate them efficiently in nondeterministic acceptance mode, i.e., the number of states is two to the power of the size of the small set.

This is a preview of subscription content, log in via an institution.

Buying options

Chapter
USD   29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD   39.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD   54.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Learn about institutional subscriptions

References

  1. Ambainis, A., Watrous, J.: Two-way finite automata with quantum and classical states. Theor. Comput. Sci. 287(1), 299–311 (2002)

    Article  MathSciNet  MATH  Google Scholar 

  2. Ambainis, A., Yakaryılmaz, A.: Automata: from mathematics to applications. In: Automata and Quantum Computing (to appear). arXiv:1507.01988

  3. Belovs, A., Montoya, J.A., Yakaryılmaz, A.: Can one quantum bit separate any pair of words with zero-error? Technical report (2016). arXiv:1602.07967

  4. Borel, A.: On free subgroups of semisimple groups. L’Enseignement Mathématique 29, 151–164 (1983)

    MathSciNet  MATH  Google Scholar 

  5. Demaine, E.D., Eisenstat, S., Shallit, J., Wilson, D.A.: Remarks on separating words. In: Holzer, M. (ed.) DCFS 2011. LNCS, vol. 6808, pp. 147–157. Springer, Heidelberg (2011)

    Chapter  Google Scholar 

  6. Díaz-Caro, A., Yakaryılmaz, A.: Affine computation and affine automaton. In: Computer Science - Theory and Applications. LNCS, vol. 9691, pp. 1–15. Springer (2016). arXiv:1602.04732

  7. Elkasapy, A., Thom, A.: About Gotô’s method showing surjectivity of word maps. Indiana Univ. Math. J. 63(5), 1553–1565 (2014). arXiv:1207.5596

    Article  MathSciNet  MATH  Google Scholar 

  8. Goralčík, P., Koubek, V.: On discerning words by automata. In: Kott, L. (ed.) Automata, Languages and Programming. LNCS, vol. 226. Springer, Heidelberg (1986)

    Google Scholar 

  9. Hirvensalo, M.: Quantum automata with open time evolution. Int. J. Nat. Comput. 1(1), 70–85 (2010)

    Article  Google Scholar 

  10. Moore, C., Crutchfield, J.P.: Quantum automata and quantum grammars. Theor. Comput. Sci. 237(1–2), 275–306 (2000)

    Article  MathSciNet  MATH  Google Scholar 

  11. Nielsen, M., Chuang, I.: Quantum Computation and Quantum Information, 10th edn. Cambridge University Press, Cambridge (2010)

    Book  MATH  Google Scholar 

  12. Robson, J.M.: Separating strings with small automata. Inf. Process. Lett. 30(4), 209–214 (1989)

    Article  MathSciNet  MATH  Google Scholar 

  13. Say, A.C.C., Yakaryılmaz, A.: Quantum finite automata: a modern introduction. In: Calude, C.S., Freivalds, R., Kazuo, I. (eds.) Gruska Festschrift. LNCS, vol. 8808, pp. 208–222. Springer, Heidelberg (2014)

    Google Scholar 

  14. Thom, A.: Convergent sequences in discrete groups. Can. Math. Bull. 56(2), 424–433 (2013). arXiv:1003.4093

    Article  MathSciNet  MATH  Google Scholar 

  15. Villagra, M., Yakaryılmaz, A.: Language recognition power and succintness of affine automata. In: Calude, C.S., Dinneen, M.J. (eds.) UCNC 2015. LNCS, vol. 9252. Springer, Heidelberg (2015)

    Google Scholar 

  16. Yakaryılmaz, A., Montoya, J.A.: On discerning strings with finite automata. In: 2015 Latin American Computing Conference, pp. 1–5. IEEE (2015)

    Google Scholar 

  17. Yakaryılmaz, A., Say, A.C.C.: Languages recognized by nondeterministic quantum finite automata. Quantum Inf. Comput. 10(9&10), 747–770 (2010)

    MathSciNet  MATH  Google Scholar 

  18. Yakaryılmaz, A., Say, A.C.C.: Unbounded-error quantum computation with small space bounds. Inf. Comput. 279(6), 873–892 (2011)

    Article  MathSciNet  MATH  Google Scholar 

Download references

Acknowledgement

We thank Andreas Thom for the discussions on our conjecture and anonymous reviewers for their helpful comments. The first author acknowledges the support provided by FP7 FET Proactive project QALGO. The second author acknowledges the support provided by Universidad Nacional de Colombia project Hermes 32083. The third author acknowledges the support provided by CAPES, grant 88881.030338/2013-01. Moreover, some parts of the work were done while the third author was visiting Bogotá, Colombia in December 2014.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to J. Andres Montoya .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2016 Springer International Publishing Switzerland

About this paper

Cite this paper

Belovs, A., Montoya, J.A., Yakaryılmaz, A. (2016). Looking for Pairs that Hard to Separate: A Quantum Approach. In: Han, YS., Salomaa, K. (eds) Implementation and Application of Automata. CIAA 2016. Lecture Notes in Computer Science(), vol 9705. Springer, Cham. https://doi.org/10.1007/978-3-319-40946-7_18

Download citation

  • DOI: https://doi.org/10.1007/978-3-319-40946-7_18

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-40945-0

  • Online ISBN: 978-3-319-40946-7

  • eBook Packages: Computer ScienceComputer Science (R0)

Publish with us

Policies and ethics