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Recently, considerable work has been directed at the development of an ultracompact X-ray free-electron laser (UCXFEL) based on emerging techniques in high-field cryogenic acceleration, with attendant dramatic improvements in electron beam brightness and state-of-the-art concepts in beam dynamics, magnetic undulators, and X-ray optics. A full conceptual design of a 1 nm (1.24 keV) UCXFEL with a length and cost over an order of magnitude below current X-ray free-electron lasers (XFELs) has resulted from this effort. This instrument has been developed with an emphasis on permitting exploratory scientific research in a wide variety of fields in a university setting. Concurrently, compact FELs are being vigorously developed for use as instruments to enable next-generation chip manufacturing through use as a high-flux, few nm lithography source. This new role suggests consideration of XFELs to urgently address emerging demands in the semiconductor device sector, as identified by recent national need studies, for new radiation sources aimed at chip manufacturing. Indeed, it has been shown that one may use coherent X-rays to perform 10–20 nm class resolution surveys of macroscopic, cm scale structures such as chips, using ptychographic laminography techniques. As the XFEL is a very promising candidate for realizing such methods, we present here an analysis of the issues and likely solutions associated with extending the UCXFEL to harder X-rays (above 7 keV), much higher fluxes, and increased levels of coherence, as well as methods of applying such a source for ptychographic laminography to microelectronic device measurements. We discuss the development path to move the concept to rapid realization of a transformative XFEL-based application, outlining both FEL and metrology system challenges. [ABSTRACT FROM AUTHOR]

We report the start-to-end modeling of our accelerator lattice design employing a laser-assisted bunch compression (LABC) scheme in an X-ray free electron laser (XFEL), using the proposed Matter-Radiation Interactions in Extremes (MaRIE) XFEL parameters. The accelerator lattice utilized a two-stage bunch compression scheme, with the first bunch compressor performing a conventional bulk compression enhancing the beam current from 20 A to 500 A, at 750 MeV. The second bunch compression was achieved by modulating the beam immediately downstream of the first bunch compressor by a laser with 1- μ m wavelength in a laser modulator, accelerating the beam to the final energy of 12 GeV, and compressing the individual 1- μ m periods of the modulated beam into a sequence of microbunches with 3-kA current spikes by the second bunch compressor. The LABC architecture presented had been developed based on the scheme of enhanced self-amplified spontaneous emission (ESASE), but operated in a disparate regime of parameters. Enabled by the novel technology of the cryogenic normal conducting radiofrequency photoinjector, we investigated an electron beam with ultra-low emittance at the starting point of the lattice design. Our work aimed at mitigating the well-known beam instabilities to preserve the beam emittance and suppress the energy spread growth. [ABSTRACT FROM AUTHOR]

The radial Schrödinger equation for a spherically symmetric potential can be regarded as a one-dimensional classical harmonic oscillator with a time-dependent spring constant. For solving classical dynamics problems, symplectic integrators are well known for their excellent conservation properties. The class of gradient symplectic algorithms is particularly suited for solving harmonic-oscillator dynamics. By use of Suzuki’s rule [Proc. Jpn. Acad., Ser. B: Phys. Biol. Sci. 69, 161 (1993)] for decomposing time-ordered operators, these algorithms can be easily applied to the Schrödinger equation. We demonstrate the power of this class of gradient algorithms by solving the spectrum of highly singular radial potentials using Killingbeck’s method [J. Phys. A 18, 245 (1985)] of backward Newton-Ralphson iterations. [ABSTRACT FROM AUTHOR]

Classical 1D X-ray Free Electron Laser (X-ray FEL) theory has stood the test of time by guiding FEL design and development prior to any full-scale analysis. Future X-ray FELs and inverse-Compton sources, where photon recoil approaches an electron energy spread value, push the classical theory to its limits of applicability. After substantial efforts by the community to find what those limits are, there is no universally agreed upon quantum approach to design and development of future X-ray sources. We offer a new approach to formulate the quantum theory for 1D X-ray FELs that has an obvious connection to the classical theory, which allows for immediate transfer of knowledge between the two regimes. We exploit this connection in order to draw quantum mechanical conclusions about the quantum nature of electrons and generated radiation in terms of FEL variables. [ABSTRACT FROM AUTHOR]

We develop an improvement to the weak laser pulse BB84 scheme for quantum key distribution, which utilizes entanglement to improve the security of the scheme and enhance its resilience to the photon-number-splitting attack. This protocol relies on the non-commutation of phase and number to detect an eavesdropper performing quantum non-demolition measurement on photon number. The potential advantages and disadvantages of this scheme are compared to the coherent decoy state protocol. [ABSTRACT FROM AUTHOR]

Autler-Townes splitting (ATS) and electromagnetically induced transparency (EIT) both yield transparency in an absorption profile, but only EIT yields strong transparency for a weak pump field due to Fano interference. Empirically discriminating EIT from ATS is important but so far has been subjective. We introduce an objective method, based on Akaike's information criterion, to test ATS vs EIT from experimental data for three-level atomic systems and determine which pertains. We apply our method to a recently reported induced-transparency experiment in superconducting-circuit quantum electrodynamics. [ABSTRACT FROM AUTHOR]

The interference between coherent and squeezed vacuum light effectively produces path entangled N00N states with very high fidelities. We show that the phase sensitivity of the above interferometric scheme with parity detection saturates the quantum Cramer-Rao bound, which reaches the Heisenberg limit when the coherent and squeezed vacuum light are mixed in roughly equal proportions. For the same interferometric scheme, we draw a detailed comparison between parity detection and a symmetric-logarithmic-derivative-based detection scheme suggested by Ono and Hofmann. [ABSTRACT FROM AUTHOR]

We present here a quantum tripwire, which is a quantum optical interrogation technique capable of detecting an intrusion with very low probability of the tripwire being revealed to the intruder. Our scheme combines interaction-free measurement (IFM) with the quantum Zeno effect in order to interrogate the presence of the intruder without interaction. The tripwire exploits a curious nonlinear behaviour of the quantum Zeno effect we discovered, which occurs in a lossy system.We also employ a statistical hypothesis testing protocol, allowing us to calculate a confidence level of IFM after a given number of trials. As a result, our quantum intruder alert system is robust against photon loss and dephasing under realistic atmospheric conditions and its design minimizes the probabilities of false positives and false negatives as well as the probability of becoming visible to the intruder. [ABSTRACT FROM AUTHOR]

We introduce decaying-dressed states for a three-level Λ system driven at one atomic transition and probed at the adjacent one. These states allow for a simple interpretation and classification of various coherent effects in such a system. [ABSTRACT FROM AUTHOR]

We show that the interference effects (similar to electromagnetically induced transparency, which was widely studied earlier in electronic transitions in optics) may appear in γ-radiation at nuclear transitions under the condition of nuclear level anticrossing. We demonstrate it also experimentally in optically thin samples of FeCO3. [ABSTRACT FROM AUTHOR]

We study nuclear elastic forward scattering of synchrotron radiation. In a simple model, we show that suppression of nuclear excitation by synchrotron radiation as well as nuclear elastic forward scattering are possible due to the formation of nuclear coherent population trapping. We consider a nucleus with ground- and excited-state nuclear momenta , , respectively. We demonstrate that nuclear coherent population trapping can be achieved for random phases of pulses in synchrotron radiation. [ABSTRACT FROM AUTHOR]

We conduct a numerical study of the possibility of using the `magic-angle' technique to suppress inhomogeneous broadening of Mössbauer spectra. We use the Floquet-state perturbation theory for the rf modulation of the Mössbauer resonance, which was adjusted to suit our purpose. A system of two nuclei of 57 Fe coupled by the dipole–dipole interaction is considered. The analysis here completes studies started in 2004, by including the dipole–dipole interaction between one nucleus in the ground state and the other in the excited state. We show that partial suppression of inhomogeneous broadening remains possible. [ABSTRACT FROM AUTHOR]

Mössbauer spectra under the presence of inhomogeneous broadening due to dipole-dipole interaction have been studied. Floquet state perturbation theory has been used for the density matrix analysis of a simple model. The parameters of 57Fe are used for simulations. We have shown that a spinning magnetic field can eliminate inhomogeneous broadening. Application to Mössbauer spectroscopy is discussed. [ABSTRACT FROM AUTHOR]

We present a numerical study of the properties of optical forces on moving atoms derived from purely stimulated processes produced by multiple adiabatic rapid-passage sequences. The optical Bloch equations are solved for a carefully timed sequence of frequency-swept pulses that can produce a force much larger than the ordinary radiative force. We describe the effects of the sweep range, peak intensity, sweep direction, number of pulses, atomic velocity, and spontaneous emission. Since the momentum of thermal atoms is much larger than that transferred by a single absorption-stimulated emission cycle, multiple repetitions are needed to make a significant velocity change. [ABSTRACT FROM AUTHOR]

A fully quantized analysis is presented of induced magneto-electric rectification in individual diatomic molecules in the steady-state regime. Good agreement is obtained between this quantum theory and a classical model that includes the same key kinematic elements but predicts temporal dynamics as well. At the molecular level, an enhanced magneto-electric optical interaction driven by dual optical fields E and H * is shown to give rise to a static electric dipole (ED) moment oriented along the propagation direction of linearly-polarized light in dielectric materials. This longitudinal Hall effect or "charge separation" interaction is quadratic with respect to the incident field strength and exhibits an induced moment that is limited by the ED transition moment of the molecular resonance. Overall, the two-photon dynamics can be described as first establishing an electric polarization and imparting orbital angular momentum on which the magnetic field exerts torque in the excited state of the molecule. Magnetic torque mediates an exchange of orbital and rotational angular momenta that de-excites the molecule and simultaneously enhances magneto-electric rectification. Material properties that affect magneto-electric response at the molecular level are identified.

We present an experimental and theoretical study of the carrier-envelope phase effects on population transfer between two bound atomic states interacting with intense ultrashort pulses. Radio frequency pulses are used to transfer population among the ground state hyperfine levels in rubidium atoms. These pulses are only a few cycles in duration and have Rabi frequencies of the order of the carrier frequency. The phase difference between the carrier and the envelope of the pulses has a significant effect on the excitation of atomic coherence and population transfer. We provide a theoretical description of this phenomenon using density matrix equations. We discuss the implications and possible applications of our results.

We study the sensitivity and resolution of phase measurement in a Mach-Zehnder interferometer with two-mode squeezed vacuum (n photons on average). We show that superresolution and sub-Heisenberg sensitivity is obtained with parity detection. In particular, in our setup, dependence of the signal on the phase evolves n times faster than in traditional schemes, and uncertainty in the phase estimation is better than 1/n, and we saturate the quantum Cramer-Rao bound.