oscillate between

oscillate between (two people or things)

To waver or go back and forth between two different, often contrary people or things that once is trying to choose. I keep oscillating between the job in New York and the one in Los Angeles. You've oscillated between Steve and Tommy long enough—they deserve an answer one way or another.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

oscillate between (someone or something and someone or something else)

to swing between (choosing) someone and someone else; to swing between (choosing) something and something else. Fred oscillated between going to college and getting a job. The boss oscillated between John and Roger.
See also: between, oscillate
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
But astronomers can see a blazar's most energetic gamma rays too well, leading the physicists to suggest that gamma rays oscillate between being photons and ALPs during their long voyage.
388) says that solar neutrinos oscillate between different flavors on the trip to Earth and that those taking a longer path have more time to oscillate into kinds of neutrinos that the sun doesn't produce.
The plate is free to oscillate between the rings, causing the fiber to twist and untwist.