Measuring vacuum polarization with high-power lasers

When exposed to intense electromagnetic fields, the quantum vacuum is expected to exhibit properties of a polarizable medium akin to a weakly nonlinear dielectric material. Various schemes have been proposed to measure such vacuum polarization effects using a combination of high- power lasers. Motivated by several planned experiments, we provide an overview of experimental signatures that have been suggested to confirm this prediction of quantum electrodynamics of real photon–photon scattering.

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Reflecting petawatt lasers off relativistic plasma mirrors: a realistic path to the Schwinger limit

High Power Laser Science and Engineering ◽

10.1017/hpl.2020.46 ◽

2021 ◽

Vol 9 ◽

Author(s):

Fabien Quéré ◽

Henri Vincenti

Keyword(s):

Light Intensity ◽

High Power ◽

Quantum Electrodynamics ◽

Laser Light ◽

Optical Breakdown ◽

Relativistic Plasma ◽

Laser Beams ◽

Relativistic Motion ◽

Quantum Vacuum ◽

High Power Lasers

Abstract The quantum vacuum plays a central role in physics. Quantum electrodynamics (QED) predicts that the properties of the fermionic quantum vacuum can be probed by extremely large electromagnetic fields. The typical field amplitudes required correspond to the onset of the ‘optical breakdown’ of this vacuum, expected at light intensities >4.7×1029 W/cm2. Approaching this ‘Schwinger limit’ would enable testing of major but still unverified predictions of QED. Yet, the Schwinger limit is seven orders of magnitude above the present record in light intensity achieved by high-power lasers. To close this considerable gap, a promising paradigm consists of reflecting these laser beams off a mirror in relativistic motion, to induce a Doppler effect that compresses the light pulse in time down to the attosecond range and converts it to shorter wavelengths, which can then be focused much more tightly than the initial laser light. However, this faces a major experimental hurdle: how to generate such relativistic mirrors? In this article, we explain how this challenge could nowadays be tackled by using so-called ‘relativistic plasma mirrors’. We argue that approaching the Schwinger limit in the coming years by applying this scheme to the latest generation of petawatt-class lasers is a challenging but realistic objective.

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Quantum Vacuum Polarization Searches with High Power Lasers Below the Pair Production Regime

Springer Series in Chemical Physics - Progress in Ultrafast Intense Laser Science ◽

10.1007/978-3-319-00521-8_9 ◽

2014 ◽

pp. 137-153 ◽

Cited By ~ 2

Author(s):

Daniele Tommasini ◽

David Novoa ◽

Luis Roso

Keyword(s):

Pair Production ◽

High Power ◽

Vacuum Polarization ◽

Quantum Vacuum ◽

High Power Lasers ◽

Production Regime

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Experimental estimates of the photon background in a potential light-by-light scattering study

New Journal of Physics ◽

10.1088/1367-2630/ac4ad3 ◽

2022 ◽

Author(s):

Leonard Doyle ◽

Pooyan Khademi ◽

Peter Hilz ◽

Alexander Sävert ◽

Georg Schaefer ◽

...

Keyword(s):

High Power ◽

Single Photon ◽

Strong Field ◽

Short Pulse ◽

Experimental Investigations ◽

Background Suppression ◽

Focal Region ◽

Quantum Vacuum ◽

Photon Scattering ◽

Residual Gas

Abstract High power short pulse lasers provide a promising route to study the strong ﬁeld eﬀects of the quantum vacuum, for example by direct photon-photon scattering in the all-optical regime. Theoretical predictions based on realistic laser parameters achievable today or in the near future predict scattering of a few photons with colliding Petawatt laser pulses, requiring single photon sensitive detection schemes and very good spatio-temporal ﬁltering and background suppression. In this article, we present experimental investigations of this photon background by employing only a single high power laser pulse tightly focused in residual gas of a vacuum chamber. The focal region was imaged onto a single-photon sensitive, time gated camera. As no detectable quantum vacuum signature was expected in our case, the setup allowed for characterization and ﬁrst mitigation of background contributions. For the setup employed, scattering oﬀ surfaces of imperfect optics dominated below the residual gas pressures of 1×10-4mbar. Extrapolation of the ﬁndings to intensities relevant for photon-photon scattering studies is discussed.

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EXPLORING QUANTUM VACUUM WITH LOW-ENERGY PHOTONS

International Journal of Quantum Information ◽

10.1142/s021974991241002x ◽

2012 ◽

Vol 10 (08) ◽

pp. 1241002 ◽

Cited By ~ 11

Author(s):

E. MILOTTI ◽

F. DELLA VALLE ◽

G. ZAVATTINI ◽

G. MESSINEO ◽

U. GASTALDI ◽

...

Keyword(s):

Cross Section ◽

Gamma Rays ◽

Quantum Electrodynamics ◽

Low Energy ◽

Quantum Field ◽

Quantum Vacuum ◽

Vacuum Fluctuations ◽

Photon Scattering ◽

Electronic Field ◽

Photon Cross Section

Although quantum mechanics (QM) and quantum field theory (QFT) are highly successful, the seemingly simplest state — vacuum — remains mysterious. While the LHC experiments are expected to clarify basic questions on the structure of QFT vacuum, much can still be done at lower energies as well. For instance, experiments like PVLAS try to reach extremely high sensitivities, in their attempt to observe the effects of the interaction of visible or near-visible photons with intense magnetic fields — a process which becomes possible in quantum electrodynamics (QED) thanks to the vacuum fluctuations of the electronic field, and which is akin to photon–photon scattering. PVLAS is now close to data-taking and if it reaches the required sensitivity, it could provide important information on QED vacuum. PVLAS and other similar experiments face great challenges as they try to measure an extremely minute effect. However, raising the photon energy greatly increases the photon–photon cross section, and gamma rays could help extract much more information from the observed light–light scattering. Here we discuss an experimental design to measure photon–photon scattering close to the peak of the photon–photon cross section, that could fit in the proposed construction of an FEL facility at the Cabibbo Lab near Frascati (Rome, Italy).

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The bound states problem in quantum electrodynamics and vacuum polarization effects in muonic atoms

Bulletin of the Russian Academy of Sciences Physics ◽

10.3103/s1062873810070166 ◽

2010 ◽

Vol 74 (7) ◽

pp. 963-965 ◽

Cited By ~ 1

Author(s):

A. A. Vasil’ev ◽

R. Kh. Gainutdinov ◽

A. A. Mutygullina ◽

M. Kh. Salakhov

Keyword(s):

Quantum Electrodynamics ◽

Bound States ◽

Vacuum Polarization ◽

Polarization Effects ◽

Muonic Atoms

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Probing Vacuum Polarization Effects with High-Intensity Lasers

Particles ◽

10.3390/particles3010005 ◽

2020 ◽

Vol 3 (1) ◽

pp. 39-61 ◽

Cited By ~ 3

Author(s):

Felix Karbstein

Keyword(s):

Electromagnetic Fields ◽

High Intensity ◽

Vacuum Polarization ◽

Laser Pulses ◽

Classical Electrodynamics ◽

Quantum Vacuum ◽

Polarization Effects ◽

High Intensity Laser ◽

Laser Experiments ◽

Intensity Laser

These notes provide a pedagogical introduction to the theoretical study of vacuum polarization effects in strong electromagnetic fields as provided by state-of-the-art high-intensity lasers. Quantum vacuum fluctuations give rise to effective couplings between electromagnetic fields, thereby supplementing Maxwell’s linear theory of classical electrodynamics with nonlinearities. Resorting to a simplified laser pulse model, allowing for explicit analytical insights, we demonstrate how to efficiently analyze all-optical signatures of these effective interactions in high-intensity laser experiments. Moreover, we highlight several key features relevant for the accurate planning and quantitative theoretical analysis of quantum vacuum nonlinearities in the collision of high-intensity laser pulses.

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