Semiclassical mean-field dynamics approach is used in combination with diatomics-in-molecules methods to study photodissociation of ionized trimers of argon, krypton, and xenon. The dynamics of photodissociation is analyzed in terms of the kinetic energy distribution of ionic and neutral fragments, fragmentation patterns, and fragmentation times. Particular attention is paid to the effect of the spin-orbit coupling and clusters temperature. Theoretical results are thoroughly compared with recent experimental as well as theoretical data.

The indistinguishability of independent single photons is presented by decomposing the single photon pulse into the mixed state of different transform-limited pulses. The entanglement between single photons and outer environment or other photons induces the distribution of the center frequencies of those transform-limited pulses and makes photons distinguishable. Only the single photons with the same transform-limited form are indistinguishable. In details, the indistinguishability of single photons from the solid-state quantum emitter and spontaneous parametric down-conversion is examined with two-photon Hong-Ou-Mandel interferometer. Moreover, experimental methods to enhance the indistinguishability are discussed, where the usage of spectral filter is highlighted.

Closed formulas are derived for the field in the focal region of a diffraction limited lens, such that the electric field component in a given direction at the focal point is larger than that of all other focused fields with the same power in the entrance pupil of the lens. Furthermore, closed formulas are derived for the corresponding optimum field distribution in the lens pupil. Focused fields with maximum longitudinal or maximum transverse are considered in detail. The latter field is similar, but not identical, to the focused linearly polarized plane wave.

Quantum optics of metallic photonic crystals is studied in this paper. Crystals are made from metallic spheres and a background dielectric material. The refractive index of the metallic spheres depends on the frequencies of the incident light and plasmons whereas the refractive index of the background material is a constant. Crystals are lightly doped with four-level nanoparticles. It is considered that nanoparticles are interacting with the metallic crystals via electron-photon interaction in the dipole approximation. The probe and pump laser fields are applied to monitor the absorption spectrum in the system. Two transparent states are predicted. One is due to the electromagnetically induced transparency and the other is due to the electron-photon interaction. For certain experimental conditions these transparent states merge into one transparent state. The effect of plasmon frequencies has also been studied. It is found that the system can be switched from a transparent state to an absorbing state just by changing the frequency of plasmons. This study can be used to makes new types of optical devices such as switches and optical transistors.

The spatial resolution of an imaging apparatus is limited by the Rayleigh diffraction bound, a consequence of the imager’s finite spatial extent. We show some $N$-photon strategies that permit resolution of details that are smaller than this bound, attaining either a $1∕\sqrt{N}$ enhancement (standard quantum limit) or a $1∕N$ enhancement (Heisenberg-like scaling) over standard techniques. In the incoherent imaging regime, the methods presented are loss resistant, since classical light sources suffice. Our results may be of importance in many applications: microscopy, telescopy, lithography, metrology, etc.

In the article by Haisch, Rueda, and Puthoff (HRP) [Phys. Rev. A 49, 678 (1994)], an explanation of inertia as an “electromagnetic resistance arising from the known spectral distortion of the zero-point field in accelerated frames” is proposed. In this paper, we show that this result is an error due to incorrect physical and mathematical assumptions associated with taking a nonrelativistic approach. At the core of HRP’s theory is a calculation of the so-called magnetic Lorentz force, which can be represented in terms of a correlation function of zero-point field (ZPF) radiation and a form factor of a small uniformly accelerated oscillator. To consider this force, the authors use a nonrelativistic approach based in fact on two main assumptions. (i) A nonrelativistic approximation of the correlation function exists. (ii) In the force integral expression, contributions of the integrand for large differences in time are damped and can be ignored. We show that their implicit nonrelativistic implementation of the correlation function is incorrect, and present as the correct expression a proper nonrelativistic limit of the exact correlation function offered earlier by Boyer. We also show that the second assumption is misguided, and the force exerted on even a slow moving accelerated oscillator “remembers” the entire history of the accelerated motion including times when its velocity could have any large value. A nonrelativistic approximation of the force leads to a contradiction. The force is fundamentally a relativistic one, which we show is equal to zero. Consequently, the interaction of the accelerated oscillator with ZPF radiation does not produce inertia, at least not for the component of the Lorentz force that HRP considered. Finally, several other calculation errors are discussed in our paper: the sign (which is of paramount importance for HRP’s theory) of HRP’s final force expression should be positive, not negative, and the high-frequency approximation used is not justified.

Total and Mulholland partial cross sections for the elastic scattering of electrons from the lanthanide atoms lanthanum to lutetium are calculated for the electron impact energy range $0⩽E⩽1\mathrm{eV}$. The recently developed Regge-pole methodology, which naturally embodies the crucial electron correlation effects together with a Thomas-Fermi-type potential incorporating the vital core-polarization interaction are used for the calculations. Dramatically sharp resonances are found to characterize the near-threshold electron elastic scattering total and Mulholland partial cross sections, whose energy positions are identified with the electron affinities (EA’s) of these atoms through a close scrutiny of the imaginary part of the complex angular momentum. The unambiguous extracted EA values of the lanthanide atoms vary from a low value of $0.016\mathrm{eV}$ for the Tm atom to a high value of $0.631\mathrm{eV}$ for the Pr atom; none is predicted to have a lower EA value than the former. All the negative ions of the lanthanide atoms can be classified through their binding energies (BE’s) as weakly bound negative ions (BE’s $<1.0\mathrm{eV}$), while only three qualify to be classified as tenuously bound (BE’$<0.1\mathrm{eV}$). Ramsauer-Townsend minima, shape resonances, and the Wigner threshold behavior for these lanthanides are also determined. Comparisons of the present calculated EA’s with those from various experimental measurements and other theoretical calculations are presented and discussed. In particular, our extracted EA value for the complicated open $d$- and $f$-subshell Ce atom agrees excellently with the most recently measured [Walter et al., Phys. Rev. A 76, 052702 (2007)] and calculated values, while for Nd and Eu the agreement with the latest calculated values of O’Malley and Beck [Phys. Rev. A 77, 012505 (2008); Phys. Rev. A 78, 012510 (2008)] is outstanding. These agreements give great credence to the already demonstrated predictive power of the Regge-pole methodology to extract unambiguous and reliable binding energies for tenuously bound and complicated open-shell negative ionic systems, requiring no a priori knowledge of the EA values whatsoever. This new perspective to the EA determination of atoms from low-energy electron elastic scattering resonances promises far-reaching implications for future accurate and reliable theoretical EA values, even for small molecules and clusters.

We consider the control problem of generating unitary transformations, which is especially relevant to current research in quantum information processing and computing, in contrast to the usual state-to-state or the more general observable expectation value control problems. A previous analysis of optimal control landscapes for unitary transformations from a kinematic perspective in the finite-dimensional unitary matrices is extended to a dynamical one in the infinite-dimensional function space of the time-dependent external field. The underlying dynamical landscape is defined as the Frobenius square norm of the difference between the control unitary matrix and the target matrix. A nonsingular adaptation matrix is introduced to provide additional freedom for exploring and manipulating key features, specifically the slope and curvature, of the control landscapes. The dynamical analysis reveals many essential geometric features of optimal control landscapes for unitary transformations, including bounds on the local landscape slope and curvature. Close examination of the curvatures at the critical points shows that the unitary transformation control landscapes are free of local traps and proper choices of the adaptation matrix may facilitate the search for optimal control fields producing desired unitary transformations, in particular, in the neighborhood of the global extrema.

Under a unified theory we investigate the formation of various types of vector solitons in two-species Bose-Einstein condensates with arbitrary scattering lengths. We then show that by tuning the interaction parameter via Feshbach resonance, transformation between different types of vector solitons is possible. Our results open up alternate ways in the quantum control of multispecies Bose-Einstein condensates.

We study the Bose-Hubbard model using the finite size density matrix renormalization group method. We obtain a complete phase diagram for a system in the presence of a harmonic trap and compare it with that of the homogeneous system. The superfluid to the Mott-insulator phase transition is investigated using different experimental signatures of these phases in quantities such as momentum distribution, visibility, condensate fraction, and the total number of bosons at a particular density. The relationships between the various experimental signatures and the phase diagram are highlighted.

The quantum self-trapping phenomenon of a Bose-Einstein condensate (BEC) represents a remarkable nonlinear effect of wide interest. By considering a purely dipolar BEC in a double-well potential, we study how the dipole orientation affects the ground-state structure and the transition between self-trapping and Josephson oscillations in dynamics. Three-dimensional numerical results and an effective two-mode model demonstrate that the onset of self-trapping of a dipolar BEC can be radically modified by the dipole orientation. We also analyze the failure of the two-mode model in predicting the rate of Josephson oscillations. We hope that our results can motivate experimental work as well as future studies of self-trapping of ultracold dipolar gases in optical lattices.

We update the ground-state energy ratio of unitary Fermi gas to noninteracting Fermi gas $\left(\xi \right)$ from the $ϵ$ expansion by including the next-to-next-to-leading-order (NNLO) term near two spatial dimensions. Interpolations of the NNLO $ϵ$ expansions around four and two spatial dimensions with the use of Padé approximants give $\xi \approx 0.360\pm 0.020$ in three dimensions with the uncertainty due to different interpolation functions. This value is consistent with the previous interpolations of the NLO $ϵ$ expansions $\xi \approx 0.377\pm 0.014$ in spite of the large NNLO corrections.

We study the propagation of electromagnetic waves in one-dimensional chirped periodic structures composed of alternating layers of negative-index (or left-handed) metamaterial and conventional dielectric, under the condition of the zero average refractive index. We consider the case when the periodic structure has a linear chirp, and the chirp is introduced by varying linearly the thickness of the layers across the structure. We apply an asymptotic analytical method for the analysis of the Bloch oscillations and find that, in a sharp contrast to ordinary periodic dielectric structures, the energy flow in multilayered stacks with metamaterials may have the opposite direction at the band edges, thus providing possibilities for the beam steering in the transmission band.

It is shown that an optical parametric amplifier inside a cavity can considerably improve the cooling of the micromechanical mirror by radiation pressure. The micromechanical mirror can be cooled from room temperature $300\mathrm{K}$ to sub-Kelvin temperatures, which is much lower than what is achievable in the absence of the parametric amplifier. This is further illustrated in case of a precooled mirror, where one can reach millikelvin temperatures starting with about $1\mathrm{K}$. Our work demonstrates the fundamental dependence of radiation pressure effects on photon statistics.

We investigate the limits of intracavity absorption spectroscopy with nonlinear media. Using a common theoretical framework, we compare the detection of a trace gas within (i) an undriven cavity with gain near and above threshold; (ii) a driven cavity with gain kept just below threshold; and (iii) a cavity driven close to the saturation point of a saturable absorber. These phase-transition-based metrology methods are typically quantum limited by spontaneous emission, and we compare them to the empty-cavity shot-noise-limited case. Although the fundamental limits achievable with nonlinear media do not surpass the empty-cavity limits, we show that nonlinear methods are more robust against certain technical noise models. This recognition may have applications in spectrometer design for devices operating in nonideal field environments.

Coherent anti-Stokes Raman scattering (CARS) interferometry is used to deplete the anti-Stokes radiation emerging from a tightly focused spot. Near-to-complete depletion of the anti-Stokes radiation is obtained when a phase-controlled local oscillator field at the anti-Stokes frequency is out of phase with the induced CARS field in the focal volume. Unlike in traditional interferometry, this depleted energy is not spatially redistributed. A theoretical analysis shows that the energy loss in the anti-Stokes channel is accompanied by an energy gain in the pump and Stokes channels. Interferometric switching of anti-Stokes radiation may offer a route toward developing high-resolution CARS microscopy.

It is shown that the modified contracted Schrödinger equation (MCSE) proposed by Alcoba and Valdemoro [Phys. Rev. A 64, 062105 (2001)] is equivalent to the original CSE of lower-order [Phys. Rev. A 14, 41 (1976)]. In particular, MCSEs of the second, third, and fourth orders are reduced to CSEs of the first, first, and second orders, respectively. Thus these MCSEs are indeterminate as the corresponding CSEs.

The preceding Comment by Yasuda [Phys. Rev. A 79, 016101 (2009)] on our earlier paper [Phys. Rev. A 64, 062105 (2001)] raises several objections about the modified contracted Schrödinger equations (MCSEs) to which we reply here. In his comment, Yasuda also questions the possibility of obtaining the exact solution of the fourth-order MCSE due to its indeterminacy. We maintain the opposite, at least from a theoretical point of view.

Analytical expressions are derived for coherent tunneling via adiabatic passage in a triple-well system with negligible central-well population at all times during the transfer. It is shown that a manipulation of the depths of the extreme wells, correlated with the time variation of the nonadjacent barriers, is essential for maintaining the vanishing population of the central well. The validity of our conditions is demonstrated with a numerical solution of the time-dependent Schrödinger equation. The transfer process is interpreted in terms of a current through the central well.

We analyze the Bures metric over the canonical thermal states for the Kitaev honeycomb mode. In this way the effects of finite temperature on topological phase transitions can be studied. Different regions in the parameter space of the model can be clearly identified in terms of different temperature scaling behavior of the Bures metric tensor. Furthermore, we show a simple relation between the metric elements and the crossover temperature between the quasicritical and the quasiclassical regions. These results extend the analysis of Zhao and Zhou [e-print arXiv:/0803.0814v1] and Yang et al. [Phys. Rev. A 78, 012304 (2008)] to finite temperatures.