Strong-field Physics Encounters Quantum Electro Dynamics

Two milestones marked the birth of quantum optics: the invention of the
laser and the formulation of the quantum theory of optical coherence. Ini-
tially regarded as “applied quantum electrodynamics (QED),” the field un-
covered non-perturbative aspects of atom–light interaction and laid the foun-
dations for strong laser–matter physics. Over time, these efforts expanded
into new domains, such as multiphoton processes, attosecond physics, ul-
trafast optics, and intense laser–matter interactions. Today, the boundaries
between quantum optics and strong-field physics are increasingly blurred,
opening new avenues toward quantum light generation, quantum state engi-
neering, and quantum information science.
The aim of this workshop was to bring together leading scientists and a
new generation of young researchers to explore these converging fields, where
many fundamental questions remain open and the potential for transforma-
tive discoveries is immense.

Report

Participants unanimously praised the high scientific quality of the meet-
ing. Its deliberately relaxed format stimulated in-depth discussions during
the sessions and fostered fruitful exchanges in informal settings. Importantly,
nearly all attendees remained engaged throughout the entire workshop, en-
suring a dynamic and collaborative atmosphere that encouraged the emer-
gence of new ideas and long-term collaborations.
A defining feature of the workshop was the strong participation of both
established leaders and early-career scientists. This intergenerational dia-
logue proved essential to the success of the event, combining long-standing
expertise with fresh perspectives and helping to identify the key challenges
and opportunities in this rapidly evolving field.
The scientific debates focused on major open questions at the intersection of:

• Quantum optics and strong-field physics, including the generation of

nonclassical light under different schemes;

• Quantum light and attosecond physics, with discussions on how non-

classical states of light can drive, tailor, and probe strong-field processes

• Quantum state engineering and entanglement, exploring routes to con-

trol and manipulate light–matter interactions for applications in quan-

tum technologies

• Quantum state characterization, addressing the development of novel

methods to reconstruct, quantify, and analyze complex electronic and

photonic quantum states.

Several new ideas emerged during the workshop, including the use of
correlated materials to create nonclassical light, novel schemes for engineering
entangled states of light and matter in strong fields, and advanced protocols
for ultrafast quantum state tomography.
A particularly vibrant discussion revolved around the characterization of
quantum light sources, a rapidly developing area that remains both techni-
cally challenging and conceptually rich. The workshop highlighted the need
for reliable tools to identify and quantify nonclassical features of light—such
as entanglement, squeezing, and higher-order photon correlations—in regimes
where intense fields, attosecond dynamics, and strong nonlinearities play a
dominant role. Strategies discussed included advanced homodyne detection
schemes and quantum state tomography adapted to ultrafast sources. These
efforts are essential not only for validating quantum light sources but also
for enabling their use in emerging quantum technologies, ranging from secure
communication to precision metrology.
The workshop underscored the importance of consolidating this interdis-
ciplinary area as a distinct research field. By connecting quantum optics,
strong-field physics, ultrafast science, and quantum technologies, it outlined
a roadmap for addressing open questions of both fundamental and applied
importance. The active involvement of young scientists, working side by side
with established leaders, ensures that the ideas seeded here will continue to
grow and shape the future of quantum science.