Coherence and multimode correlations from vacuum fluctuations in a microwave superconducting cavity

Pasi Lähteenmäki, Gheorghe Sorin Paraoanu, Juha Hassel, Pertti J. Hakonen*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

31 Citations (Scopus)
149 Downloads (Pure)

Abstract

The existence of vacuum fluctuations is one of the most important predictions of modern quantum field theory. In the vacuum state, fluctuations occurring at different frequencies are uncorrelated. However, if a parameter in the Lagrangian of the field is modulated by an external pump, vacuum fluctuations stimulate spontaneous downconversion processes, creating squeezing between modes symmetric with respect to half of the frequency of the pump. Here we show that by double parametric pumping of a superconducting microwave cavity, it is possible to generate another type of correlation, namely coherence between photons in separate frequency modes. The coherence correlations are tunable by the phases of the pumps and are established by a quantum fluctuation that stimulates the simultaneous creation of two photon pairs. Our analysis indicates that the origin of this vacuum-induced coherence is the absence of which-way information in the frequency space.

Original languageEnglish
Article number12548
Pages (from-to)1-7
JournalNature Communications
Volume7
DOIs
Publication statusPublished - 26 Aug 2016
MoE publication typeA1 Journal article-refereed

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