Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2511.07195

Survival acceleration

Yakov Bloch, Avshalom C. Elitzur

quant-phSubmitted Nov 10, 2025• Announced Nov 11, 2025• 0 citations
arXivHTMLPDF

Abstract

Relativistic time dilation implies that an accelerating excited atom would have its lifetime prolonged in the lab frame. In this paper, we demonstrate a complementary effect: Longer-lived excited atoms turn out to have been accelerated. We propose the following experiment. An excited atom is prepared in a superposition of momenta. Due to relativistic time dilation, in the lab frame, the decay rate of components with higher momentum is diminished. As time passes without the atom emitting a photon, higher-momentum components become more probable. This results in a time-dependent shift of the expectation value of momentum. Taking into account first-order relativistic corrections, we calculate the force and acceleration undergone by the atom due to the fact that it did not emit a photon.

Comments
4 pages, 1 figure

Related papers

Quantum time dilation in atomic spectra

Piotr T. Grochowski, Alexander R. H. Smith, Andrzej Dragan +1 more

Quantum time dilation occurs when a clock moves in a superposition of relativistic momentum wave packets.The lifetime of an excited hydrogenlike atom can be used as a clock, which we use to demonstrate how quantum time dilation manifests in a spontaneous emission process.The resulting emission rate differs when compared with the emission rate of an atom prepared in a mixture of momentum wave packets at order v 2 /c 2 .This effect is accompanied by a quantum correction to the Doppler shift due to the coherence between momentum wave packets.This quantum Doppler shift affects the spectral line shape at order v/c.However, its effect on the decay rate is suppressed when compared with the effect of quantum time dilation.We argue that spectroscopic experiments offer a technologically feasible platform to explore the effects of quantum time dilation.

arXiv:2006.10084•Physical Review Research•Apr 19, 2021•19 citations

Prolonging the Lifetime of Relativistic Particles by Self-Accelerating Dirac Wavepackets

Ido E. Kaminer, Mikael C. Rechtsman, Rivka Bekenstein +2 more

We show that shaping the wavepackets of Dirac particles can alter fundamental relativistic effects such as length contraction and time dilation. For example, shaping decaying particles as self-accelerating Dirac wavepackets extends their lifetime

•Jan 1, 2015•0 citations

Time Dilation in Relativistic Quantum Decay Laws of Moving Unstable Particles

Filippo Giraldi

The relativistic quantum decay laws of moving unstable particles are analyzed for a general class of mass distribution densities which behave as power laws near the (nonvanishing) lower bound μ0 of the mass spectrum. The survival probability Pp(t) , the instantaneous mass Mp(t) , and the instantaneous decay rate Γp(t) of the moving unstable particle are evaluated over short and long times for an arbitrary value p of the (constant) linear momentum. The ultrarelativistic and nonrelativistic limits are studied. Over long times, the survival probability Pp(t) is approximately related to the survival probability at rest P0(t) by a scaling law. The scaling law can be interpreted as the effect of the relativistic time dilation if the asymptotic value Mp∞ of the instantaneous mass is considered as the effective mass of the unstable particle over long times. The effective mass has magnitude μ0 at rest and moves with linear momentum p or, equivalently, with constant velocity 1/1+μ02/p2 . The instantaneous decay rate Γp(t) is approximately independent of the linear momentum p , over long times, and, consequently, is approximately invariant by changing reference frame.

arXiv:1803.07709•Advances in High Energy Physics•May 29, 2018•4 citations

Non-classical Behavior of Moving Relativistic Unstable Particles

K. Urbanowski

We study the survival probability of moving relativistic unstable particles with definite momentum $\vec{p} \neq 0$. The amplitude of the survival probability of these particles is calculated using its integral representation. We found decay curves of such particles for the quantum mechanical models considered. These model studies show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-expo\-nen\-tial form of the survival probability, should occur much earlier than it follows from the classical standard approach resolving itself into replacing time $t$ by $t/γ$ (where $γ$ is the relativistic Lorentz factor) in the formula for the survival probability and that the survival probabilities should tend to zero as $t\rightarrow \infty$ much slower than one would expect using classical time dilation relation. Here we show also that for some physically admissible models of unstable states the computed decay curves of the moving particles have fluctuating form at relatively short times including times of order of the lifetime.

arXiv:1506.05076•Acta Physica Polonica B•Jan 1, 2017•6 citations

Decay law of relativistic particles: Quantum theory meets special relativity

K. Urbanowski

Late time properties of moving relativistic particles are studied. Within the proper relativistic treatment of the problem we find decay curves of such particles and we show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-exponential form of the survival amplitude, occur much earlier than it follows from the classical standard approach boiled down to replace time t by t/γL (where γL is the relativistic Lorentz factor) in the formula for the survival probability. The consequence is that fluctuations of the corresponding decay curves can appear much earlier and much more unstable particles have a chance to survive up to these times or later. It is also shown that fluctuations of the instantaneous energy of the moving unstable particles have a similar form as the fluctuations in the particle rest frame but they are seen by the observer in his rest system much earlier than one could expect replacing t by t/γL in the corresponding expressions for this energy and that the amplitude of these fluctuations can be even larger than it follows from the standard approach. All these effects seem to be important when interpreting some accelerator experiments with high energy unstable particles and the like (possible connections of these effects with GSI anomaly are analyzed) and some results of astrophysical observations.

arXiv:1408.6564•Physics Letters B•Sep 5, 2014•32 citations

Nonclassical face of quantum decay processes

K. Urbanowski

A detailed analysis of the quantum decay processes shows the survival probability ( t ) can not take that exponential form at any time interval including times smaller than the lifetime τ . We show that for times t ∼ τ and for the times later than τ the form of ( t ) looks as a composition of an oscillating and exponential functions. The amplitude of these oscillations is very small for t ≪ τ and grows with increasing time and depends on the model considered. We also study the survival probability of moving relativistic unstable particles with definite momentum : It turns out that late time deviations of the survival probability of these particles from the exponential-like form of the decay law should occur much earlier than it follows from the classical standard approach resolving itself into replacing time t by t / γ (where γ is the relativistic Lorentz factor) in the formula for the survival probability ( t ).

Journal of Physics Conference Series•Aug 1, 2017•0 citations
Relativistic time dilation implies that an accelerating excited atom would have its lifetime prolonged in the lab frame. In this paper, we demonstrate a complementary effect: Longer-lived excited atoms turn out to have been accelerated. We propose the following experiment. An excited atom is prepared in a superposition of momenta. Due to relativistic time dilation, in the lab frame, the decay rate of components with higher momentum is diminished. As time passes without the atom emitting a photon, higher-momentum components become more probable. This results in a time-dependent shift of the expectation value of momentum. Taking into account first-order relativistic corrections, we calculate the force and acceleration undergone by the atom due to the fact that it did not emit a photon.
Quantum time dilation occurs when a clock moves in a superposition of relativistic momentum wave packets.The lifetime of an excited hydrogenlike atom can be used as a clock, which we use to demonstrate how quantum time dilation manifests in a spontaneous emission process.The resulting emission rate differs when compared with the emission rate of an atom prepared in a mixture of momentum wave packets at order v 2 /c 2 .This effect is accompanied by a quantum correction to the Doppler shift due to the coherence between momentum wave packets.This quantum Doppler shift affects the spectral line shape at order v/c.However, its effect on the decay rate is suppressed when compared with the effect of quantum time dilation.We argue that spectroscopic experiments offer a technologically feasible platform to explore the effects of quantum time dilation.
The relativistic quantum decay laws of moving unstable particles are analyzed for a general class of mass distribution densities which behave as power laws near the (nonvanishing) lower bound μ0 of the mass spectrum. The survival probability Pp(t) , the instantaneous mass Mp(t) , and the instantaneous decay rate Γp(t) of the moving unstable particle are evaluated over short and long times for an arbitrary value p of the (constant) linear momentum. The ultrarelativistic and nonrelativistic limits are studied. Over long times, the survival probability Pp(t) is approximately related to the survival probability at rest P0(t) by a scaling law. The scaling law can be interpreted as the effect of the relativistic time dilation if the asymptotic value Mp∞ of the instantaneous mass is considered as the effective mass of the unstable particle over long times. The effective mass has magnitude μ0 at rest and moves with linear momentum p or, equivalently, with constant velocity 1/1+μ02/p2 . The instantaneous decay rate Γp(t) is approximately independent of the linear momentum p , over long times, and, consequently, is approximately invariant by changing reference frame.
We study the survival probability of moving relativistic unstable particles with definite momentum p⃗≠0\vec{p} \neq 0p​=0. The amplitude of the survival probability of these particles is calculated using its integral representation. We found decay curves of such particles for the quantum mechanical models considered. These model studies show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-expo\-nen\-tial form of the survival probability, should occur much earlier than it follows from the classical standard approach resolving itself into replacing time ttt by t/γt/γt/γ (where γγγ is the relativistic Lorentz factor) in the formula for the survival probability and that the survival probabilities should tend to zero as t→∞t\rightarrow \inftyt→∞ much slower than one would expect using classical time dilation relation. Here we show also that for some physically admissible models of unstable states the computed decay curves of the moving particles have fluctuating form at relatively short times including times of order of the lifetime.
Late time properties of moving relativistic particles are studied. Within the proper relativistic treatment of the problem we find decay curves of such particles and we show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-exponential form of the survival amplitude, occur much earlier than it follows from the classical standard approach boiled down to replace time t by t/γL (where γL is the relativistic Lorentz factor) in the formula for the survival probability. The consequence is that fluctuations of the corresponding decay curves can appear much earlier and much more unstable particles have a chance to survive up to these times or later. It is also shown that fluctuations of the instantaneous energy of the moving unstable particles have a similar form as the fluctuations in the particle rest frame but they are seen by the observer in his rest system much earlier than one could expect replacing t by t/γL in the corresponding expressions for this energy and that the amplitude of these fluctuations can be even larger than it follows from the standard approach. All these effects seem to be important when interpreting some accelerator experiments with high energy unstable particles and the like (possible connections of these effects with GSI anomaly are analyzed) and some results of astrophysical observations.
A detailed analysis of the quantum decay processes shows the survival probability ( t ) can not take that exponential form at any time interval including times smaller than the lifetime τ . We show that for times t ∼ τ and for the times later than τ the form of ( t ) looks as a composition of an oscillating and exponential functions. The amplitude of these oscillations is very small for t ≪ τ and grows with increasing time and depends on the model considered. We also study the survival probability of moving relativistic unstable particles with definite momentum : It turns out that late time deviations of the survival probability of these particles from the exponential-like form of the decay law should occur much earlier than it follows from the classical standard approach resolving itself into replacing time t by t / γ (where γ is the relativistic Lorentz factor) in the formula for the survival probability ( t ).