What the study found
The paper argues that a theory of time based on wavefunction collapse in general relativity can produce emergent time and physical excitations. It also says the scale factor, a measure of cosmic expansion, increases monotonically and can act as a clock.
Why the authors say this matters
The authors suggest this framework may help explain how time, an arrow of time, and different graviton modes arise from the underlying theory. They also conclude that the scalar mode may be a viable candidate for dark matter.
What the researchers tested
The study develops a theory in which quantum states that violate the momentum and Hamiltonian constraints represent instances of time. It uses stochastic fluctuations of the lapse and shift, together with semi-classical and adiabatic approximations, to examine a cosmological constant-dominated universe in the limit of large space dimension.
What worked and what didn't
Under wavefunction collapse, the authors report that scalar, vector, and tensor gravitons arise as physical excitations, and that tensor gravitons show emergent unitary dynamics in the long-time limit. They also report that the vector mode is uniformly suppressed, while the scalar mode decays at a rate proportional to its wave vector; large-wavelength scalar excitations survive longer, whereas short-wavelength ones decay quickly.
What to keep in mind
The abstract says these results are demonstrated for a cosmological constant-dominated universe, so the scope is limited to that setting. It also notes that the approximations are controlled only in the limit of large space dimension.
Key points
- The paper proposes that wavefunction collapse can generate emergent time in general relativity.
- The scale factor is described as increasing monotonically and serving as a clock.
- Tensor gravitons are reported to show emergent unitary dynamics at long times.
- The vector mode is said to be uniformly suppressed at all length scales.
- The scalar mode decays at a rate proportional to wave vector and is described as a possible dark matter candidate.
Disclosure
- Research title:
- Wavefunction collapse yields emergent time and damped extra modes
- Authors:
- Sung-Sik Lee
- Institutions:
- McMaster University, Perimeter Institute
- Publication date:
- 2026-04-22
- OpenAlex record:
- View
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