A bstract In theories with renormalons the perturbative series is factorially divergent even
after restricting to a given order in 1/N, making the 1/N expansion a natural testing ground for …

A bstract We study the free energy of integrable, asymptotically free field theories in two
dimensions coupled to a conserved charge. We develop methods to obtain analytic …

We revisit the path-integral approach to the wave function of the Universe by utilizing
Lefschetz thimble analyses and resurgence theory. The traditional Euclidean path integral of …

We analyze a family of generalized energy densities in integrable quantum field theories in
the presence of an external field coupled to a conserved charge. By using the Wiener-Hopf …

A bstract We make use of Borel resummation to extract the exact time dependence from the
divergent series found in the context of stochastic inflation. Correlation functions of self …

A bstract We study the perturbative expansion of the ground state energy in the presence of
an external field coupled to a conserved charge in the integrable two-dimensional O (4) …

We investigate the ground-state energy of the integrable two dimensional O (3) sigma model
in a magnetic field. By determining a large number of perturbative coefficients we explore …

We study the resurgent trans-series for the free energy of the two-dimensional O (4) sigma
model in a magnetic field. Exploiting integrability, we obtain very high-order perturbative …

Many observables in quantum field theory can be expressed in terms of trans-series, in
which one adds to the perturbative series a typically infinite sum of exponentially small …

Some sigma models which admit a theta angle are integrable at both $\vartheta= 0$ and
$\vartheta=\pi $. This includes the well-known $ O (3) $ sigma model and two families of …