Atomic supersymmetry

Atomic supersymmetry is a quantum-mechanical supersymmetry connecting the properties of different atoms and ions. A short description of some established results in the subject are provided and a few recent developments are discussed including the extension to parabolic coordinates and the calculation of Stark maps using supersymmetry-based models

Solid quantization for non-point particles

In quantum field theory, elemental particles are assumed to be point particles. As a result, the loop integrals are divergent in many cases. Regularization and renormalization are necessary in order to get the physical finite results from the infinite, divergent loop integrations. We propose new quantization conditions for non-point particles. With this solid quantization, divergence could be treated systematically. This method is useful for effective field theory which is on hadron degrees of freedom. The elemental particles could also be non-point ones. They can be studied in this approach as well.Comment: 7 page

Neutron star sensitivities in Ho\u159ava gravity after GW170817

Horava gravity breaks boost invariance in the gravitational sector by introducing a preferred time foliation. The dynamics of this preferred slicing is governed, in the low-energy limit suitable for most astrophysical applications, by three dimensionless parameters $alpha$, $eta$ and $lambda$. The first two of these parameters are tightly bound by solar system and gravitational wave propagation experiments, but $lambda$ remains relatively unconstrained ($0leqlambdalesssim 0.01-0.1$). We restrict here to the parameter space region defined by $alpha=eta=0$ (with $lambda$ kept generic), which in a previous paper we showed to be the only one where black hole solutions are non-pathological at the universal horizon, and we focus on possible violations of the strong equivalence principle in systems involving neutron stars. We compute neutron star 'sensitivities', which parametrize violations of the strong equivalence principle at the leading post-Newtonian order, and find that they vanish identically, like in the black hole case, for $alpha=eta=0$ and generic $lambda eq0$. This implies that no violations of the strong equivalence principle (neither in the conservative sector nor in gravitational wave fluxes) can occur at the leading post-Newtonian order in binaries of compact objects, and that data from binary pulsars and gravitational interferometers are unlikely to further constrain $lambda$

Long-term evolution and revival structure of Rydberg wave packets

It is known that, after formation, a Rydberg wave packet undergoes a series of collapses and revivals within a time period called the revival time, t_{\rm rev}, at the end of which it is close to its original shape. We study the behavior of Rydberg wave packets on time scales much greater than t_{\rm rev}. We show that after a few revival cycles the wave packet ceases to reform at multiples of the revival time. Instead, a new series of collapses and revivals commences, culminating after a time period t_{\rm sr} \gg t_{\rm rev} with the formation of a wave packet that more closely resembles the initial packet than does the full revival at time t_{\rm rev}. Furthermore, at times that are rational fractions of t_{\rm sr}, the square of the autocorrelation function exhibits large peaks with periodicities that can be expressed as fractions of the revival time t_{\rm rev}. These periodicities indicate a new type of fractional revival occurring for times much greater than t_{\rm rev}. A theoretical explanation of these effects is outlined

The revival structure of Rydberg wave packets beyond the revival time

After a Rydberg wave packet forms, it is known to undergo a series of collapses and revivals within a time period called the revival time t_{\rm rev}, at the end of which it resembles its original shape. We study the behavior of Rydberg wave packets on time scales much greater than t_{\rm rev}. We find that after a few revival cycles the wave packet ceases to reform at multiples of the revival time. Instead, a new series of collapses and revivals commences, culminating after a time period t_{\rm sr} \gg t_{\rm rev} with the formation of a wave packet that more closely resembles the initial packet than does the full revival at time t_{\rm rev}. Furthermore, at times that are rational fractions of t_{\rm sr}, we show that the motion of the wave packet is periodic with periodicities that can be expressed as fractions of the revival time t_{\rm rev}. These periodicities indicate a new type of fractional revival, occurring for times much greater than t_{\rm rev}. We also examine the effects of quantum defects and laser detunings on the revival structure of Rydberg wave packets for alkali-metal atoms

Lorentz-Violating Extension of the Standard Model

In the context of conventional quantum field theory, we present a general Lorentz-violating extension of the minimal SU(3) x SU(2) x U(1) standard model including CPT-even and CPT-odd terms. It can be viewed as the low-energy limit of a physically relevant fundamental theory with Lorentz-covariant dynamics in which spontaneous Lorentz violation occurs. The extension has gauge invariance, energy-momentum conservation, and covariance under observer rotations and boosts, while covariance under particle rotations and boosts is broken. The quantized theory is hermitian and power-counting renormalizable, and other desirable features such as microcausality, positivity of the energy, and the usual anomaly cancellation are expected. Spontaneous symmetry breaking to the electromagnetic U(1) is maintained, although the Higgs expectation is shifted by a small amount relative to its usual value and the $Z^0$ field acquires a small expectation. A general Lorentz-breaking extension of quantum electrodynamics is extracted from the theory, and some experimental tests are considered. In particular, we study modifications to photon behavior. One possible effect is vacuum birefringence, which could be bounded from cosmological observations by experiments using existing techniques. Radiative corrections to the photon propagator are examined. They are compatible with spontaneous Lorentz and CPT violation in the fermion sector at levels suggested by Planck-scale physics and accessible to other terrestrial laboratory experiments

Nonrelativistic Quantum Hamiltonian for Lorentz Violation

A method is presented for deriving the nonrelativistic quantum hamiltonian of a free massive fermion from the relativistic lagrangian of the Lorentz-violating standard-model extension. It permits the extraction of terms at arbitrary order in a Foldy-Wouthuysen expansion in inverse powers of the mass. The quantum particle hamiltonian is obtained and its nonrelativistic limit is given explicitly to third order