Combining Word Semantics within Complex Hilbert Space for Information Retrieval

  • Peter WittekEmail author
  • Bevan Koopman
  • Guido Zuccon
  • Sándor Darányi
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8369)


Complex numbers are a fundamental aspect of the mathematical formalism of quantum physics. Quantum-like models developed outside physics often overlooked the role of complex numbers. Specifically, previous models in Information Retrieval (IR) ignored complex numbers. We argue that to advance the use of quantum models of IR, one has to lift the constraint of real-valued representations of the information space, and package more information within the representation by means of complex numbers. As a first attempt, we propose a complex-valued representation for IR, which explicitly uses complex valued Hilbert spaces, and thus where terms, documents and queries are represented as complex-valued vectors. The proposal consists of integrating distributional semantics evidence within the real component of a term vector; whereas, ontological information is encoded in the imaginary component. Our proposal has the merit of lifting the role of complex numbers from a computational byproduct of the model to the very mathematical texture that unifies different levels of semantic information. An empirical instantiation of our proposal is tested in the TREC Medical Record task of retrieving cohorts for clinical studies.


Semantic Word Complex-valued Representation Complex-valued Hilbert Space Distributional Semantics Quantum-like Model 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Peter Wittek
    • 1
    Email author
  • Bevan Koopman
    • 2
    • 3
  • Guido Zuccon
    • 2
  • Sándor Darányi
    • 1
  1. 1.University of BoråsBoråsSweden
  2. 2.Australian e-Health Research CentreCSIROBrisbaneAustralia
  3. 3.Queensland University of TechnologyBrisbaneAustralia

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