Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1512.00637

Keldysh Field Theory for Driven Open Quantum Systems

L. M. Sieberer·M. Buchhold·S. Diehl
View original source ↗Read source document ↗Export metadata ↓

Abstract

Recent experimental developments in diverse areas - ranging from cold atomic gases over light-driven semiconductors to microcavity arrays - move systems into the focus, which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating genuine non-equilibrium scenarios without immediate counterpart in condensed matter. This concerns both their non-thermal flux equilibrium states, as well as their many-body time evolution. It is a challenge to theory to identify novel instances of universal emergent macroscopic phenomena, which are tied unambiguously and in an observable way to the microscopic drive conditions. In this review, we discuss some recent results in this direction. Moreover, we provide a systematic introduction to the open system Keldysh functional integral approach, which is the proper technical tool to accomplish a merger of quantum optics and many-body physics, and leverages the power of modern quantum field theory to driven open quantum systems.

Explore related subjects

cond-mat.quant-gas

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

L. M. Sieberer, M. Buchhold, S. Diehl. 2016-08-04. Keldysh Field Theory for Driven Open Quantum Systems. https://doi.org/10.1088/0034-4885%2F79%2F9%2F096001

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Borromean Criticality in Two Dimensions

The characteristic feature of counterflow superfluids consisting of $N\geq 3$ components -- the so-called Borromean supercounterfluids (BSCF) -- is the presence of $N$ distinct elementary topological excitations (vortices) despite having only $N-1$ independent Goldstone modes. We show that this remarkable property clearly manifests itself at the Berezinskii-Kosterlitz-Thouless-type transition from the BSCF to the normal state, under the conditions of slight to moderate deviations from the case of exact intercomponent symmetry. More generally, our analysis also applies to any multicomponent superfluid with intercomponent drag fine-tuned to the value when certain composite vortices compete energetically with elementary ones.

cond-mat.quant-gas↗
arXiv2026

Trimer Dynamics in Floquet-driven arrays of Rydberg Atoms

We analyze the WAHUHA Floquet protocol recently applied to arrays of Rydberg atoms and derive beyond-leading-order corrections in the high-frequency expansion of the effective spin theory. We find that an appropriate choice of the pulses times can enforce an approximate symmetry corresponding to the conservation of the total magnetization. The interaction channels emerging from higher-order Floquet terms affect three-body bound states (\emph{trimers}), which gain a significant mobility. We estimate the corresponding enhancement in 1D spin chains and conclude that their dynamics is within experimental reach. Detrimental effects due to the proliferation of particles outside of the trimer magnetization sector are found to occur and spread on time-scales slower than the trimer propagation. We further show that long-range interactions enhance trimer propagation and that two-dimensional triangular geometries can host energetically isolated trimer bands, providing a possible route to reduce resonant mixing with higher-magnetization sectors. Our results establish a concrete route to realizing mobile multiparticle bound states in Floquet-engineered Rydberg platforms.

cond-mat.quant-gas↗
arXiv2026

Three- and four-boson systems expanded around the unitarity limit: Application to $^4$He molecules

The three- and four-boson systems with a large scattering length and a short effective range in the two-body sector are studied in the framework of Short-Range Effective Field Theory (SREFT). The starting point (leading order) of the EFT is taken to be the universal unitarity limit, where the two-body sector is parameter-free and only one three-body parameter enters. In this limit, physical systems manifest discrete scale invariance. Deviations from universality arising from finite scattering-length and effective-range corrections, as well as a four-body force required by renormalization, are included perturbatively at next-to-leading order. The three-body ground state and its associated four-body ground and first-excited states are studied using the Faddeev-Yakubovsky (FY) formalism and a complementary diagrammatic approach. By employing techniques to remove contributions from deep trimers in tetramer calculations, we extend our analysis to larger cutoffs than previously accessible within the FY approach to SREFT. Our results for binding energies and radii of $^4$He three- and four-atom systems converge well to results obtained with sophisticated phenomenological potentials. These successes suggest that the physics of $^4$He atomic clusters is governed by only small deviations from discrete scale invariance.

cond-mat.quant-gas↗