Self-generated quantum gauge fields in arrays of Rydberg atoms

As shown in recent experiments [V. Lienhard et al., Phys. Rev. X 10, 021031 (2020)], spin-orbit coupling in systems of Rydberg atoms can give rise to density-dependent Peierls Phases in second-order hoppings of Rydberg spin excitations and nearest-neighbor (NN) repulsion. We here study theoretically a one-dimensional zig-zag ladder system of such spin-orbit coupled Rydberg atoms at half filling. The second-order hopping is shown to be associated with an effective gauge field, which in mean-field approximation is static and homogeneous. Beyond the mean-field level the gauge potential attains a transverse quantum component whose amplitude is dynamical and linked to density modulations. We here study the effects of this to the possible ground-state phases of the system. In a phase where strong repulsion leads to a density wave, we find that as a consequence of the induced quantum gauge field a regular pattern of current vortices is formed. However also in the absence of density-density interactions the quantum gauge field attains a non-vanishing amplitude. Above a certain critical strength of the second-order hopping the energy gain due to gauge-field induced transport overcomes the energy cost from the associated build-up of density modulations leading to a spontaneous generation of the quantum gauge field.

Atom-optically synthetic gauge fields for a noninteracting Bose gas

Synthetic gauge fields in synthetic dimensions are now of great interest. This concept provides a convenient manner for exploring topological phases of matter. Here, we report on the first experimental realization of an atom-optically synthetic gauge field based on the synthetic momentum-state lattice of a Bose gas of 133Cs atoms, where magnetically controlled Feshbach resonance is used to tune the interacting lattice into noninteracting regime. Specifically, we engineer a noninteracting one-dimensional lattice into a two-leg ladder with tunable synthetic gauge fields. We observe the flux-dependent populations of atoms and measure the gauge field-induced chiral currents in the two legs. We also show that an inhomogeneous gauge field could control the atomic transport in the ladder. Our results lay the groundwork for using a clean noninteracting synthetic momentum-state lattice to study the gauge field-induced topological physics.

Decomposition of the static potential in the Maximal Abelian gauge

Decomposition of SU(2) gauge field into monopole and monopoleless components is studied in SU(2) gluodynamics and in QC2D with zero and nonzero quark chemical potential after fixing MA gauge. For both components we calculate respective static potential and compare their sum with the nonabelian static potential. We demonstrate good agreement in the confinement phase and discuss the implications of our results.

Standard Model in Weyl conformal geometry

We study the Standard Model (SM) in Weyl conformal geometry. This embedding is truly minimal with no new fields beyond the SM spectrum and Weyl geometry. The action inherits a gauged scale symmetry D(1) (known as Weyl gauge symmetry) from the underlying geometry. The associated Weyl quadratic gravity undergoes spontaneous breaking of D(1) by a geometric Stueckelberg mechanism in which the Weyl gauge field ($$\omega _\mu $$ ω μ ) acquires mass by “absorbing” the spin-zero mode of the $${\tilde{R}}^2$$ R ~ 2 term in the action. This mode also generates the Planck scale and the cosmological constant. The Einstein-Proca action emerges in the broken phase. In the presence of the SM, this mechanism receives corrections (from the Higgs) and it can induce electroweak (EW) symmetry breaking. The EW scale is proportional to the vev of the Stueckelberg field. The Higgs field ($$\sigma $$ σ ) has direct couplings to the Weyl gauge field ($$\sigma ^2\omega _\mu \omega ^\mu $$ σ 2 ω μ ω μ ). The SM fermions only acquire such couplings for non-vanishing kinetic mixing of the gauge fields of $$D(1)\times U(1)_Y$$ D ( 1 ) × U ( 1 ) Y . If this mixing is present, part of the mass of Z boson is not due to the usual Higgs mechanism, but to its mixing with massive $$\omega _\mu $$ ω μ . Precision measurements of Z mass then set lower bounds on the mass of $$\omega _\mu $$ ω μ which can be light (few TeV). In the early Universe the Higgs field can have a geometric origin, by Weyl vector fusion, and the Higgs potential can drive inflation. The dependence of the tensor-to-scalar ratio r on the spectral index $$n_s$$ n s is similar to that in Starobinsky inflation but mildly shifted to lower r by the Higgs non-minimal coupling to Weyl geometry.

The History of Science as “the History of Rare Fluctuations of Thought and Scientific Work ... like Archimedes and Newton”

The article examines the scientific and biographical approach to the history of science and especially its version, which can be called the method of personification of history. Both methods were proposed by S. I. Vavilov and both are associated with his understanding of the history of science as “a sequence of rare fluctuations of thought and scientific work ... like Archimedes and Newton”. The method of personification of history is illustrated on a number of large-scale fragments of the history of physics of the 19th and 20th centuries. Five cases of such personification are considered. This is, first of all, the case of G. Monge, who personified the science and technology of revolutionary France (analyzed by Vavilov himself). Two casesrefer to two scientific revolutions in physics of the 20th century (to the quantum-relativistic – the case of A. Einstein and to the gauge-field – the case of M. Gell-Mann). And, finally, two cases of personification of the history of Russian physics. In the first, not one, but two essentially opposite key figures of Russian physics on the eve of the scientific revolution are considered: N. A. Umov and P. N. Lebedev. The second case is S. I. Vavilov himself, who in many ways personified the development of Soviet physics in the first half of the 20th century.

Conserved momenta of ferromagnetic solitons through the prism of differential geometry

The relation between symmetries and conservation laws for solitons in a ferromagnet is complicated by the presence of gyroscopic (precessional) forces, whose description in the Lagrangian framework involves a background gauge field. This makes canonical momenta gauge-dependent and requires a careful application of Noether’s theorem. We show that Cartan’s theory of differential forms is a natural language for this task. We use it to derive conserved momenta of the Belavin–Polyakov skyrmion, whose symmetries include translation, global spin rotation, and dilation.