Diplomatic background of the Crimean war

Thesis (M.A.)--Boston University, 1932. This item was digitized by the Internet Archive

Repeat Offenders: The Constitutionality of the Dangerous Special Offender Act

United States v. Stewart, 531 F.2d 326 (6th Cir.), cert. denied, 96 S.Ct. 2629 (1976). In 1970, under heavy nationwide pressure to take action against the escalating crime problem, Congress passed the Organized Crime Control Act. Undoubtedly the most controversial new provision of this Act is Title X of the Dangerous Special Offender Act, which provides increased penalties for habitual or professional criminals convicted of a triggering felony. It had generally been recognized that a federal recidivist statute of this kind was long overdue. According to the National Commission on the Causes and Prevention of Violence, the greatest proportion of all serious violence is committed by repeat offenders, accounting not only for a higher rate, but also a greater degree of violence. In drafting the Act, Congress made use of the conclusions of many prestigious legal organizations, whose studies had demonstrated that some form of increased sentencing for dangerous offenders was necessary not only to protect the community, but also, to begin the process of reduction of prison use as to non-dangerous offenders. In contrast with these approving reports, the proposed Act met with serious opposition in Congress by the American Civil Liberties Union, by the Association of the Bar of the City of New York, and by a number of concerned congressmen. These groups raised difficult constitutional questions dealing with due process, vagueness, double jeopardy, cruel and unusual punishment, and equal protection, as well as many evidentiary and policy problems. While the bill appears to be a laudable attempt to remove a very dangerous element in our society, a more careful examination reveals potential pitfalls in its definitions and sentencing provisions. The bill was passed in 1970 over many constitutional objections, but since that time Title X has rarely been invoked by the Justice Department, perhaps because of uneasiness or lack of confidence in its acceptance by the courts. The result has been that the issue of its constitutionality was not resolved in any United States Circuit Court of Appeals until the Act was upheld by the Sixth Circuit in United States v. Stewart. Thus the Stewart case is of significant legal interest, since it marks the government\u27s first definitive court victory at the appeals court level, and may signal more extensive use of the law by the Justice Department

Experiments with Frequency Converted Photons from a Trapped Atomic Ion

Trapped atomic ions excel as local quantum information processing nodes, given their long qubit coherence times combined with high fidelity single-qubit and multi-qubit gate operations. Trapped ion systems also readily emit photons as flying qubits, making efforts towards construction of large-scale and long-distance trapped-ion-based quantum networks very appealing. Two-node trapped-ion quantum networks have demonstrated a desirable combination of high-rate and high-fidelity remote entanglement generation, but these networks have been limited to only a few meters in length. This limitation is primarily due to large fiber-optic propagation losses experienced by the ultraviolet and visible photons typically emitted by trapped ions. These wavelengths are also incompatible with existing telecommunications technology and infrastructure, as well as being incompatible with many other emerging quantum technologies designed for useful tasks such as single photon storage, measurement, and routing, limiting the scalability of ion-based networks. In this thesis, I discuss a series of experiments where we introduce quantum frequency conversion to convert single photons at 493 nm, produced by and entangled with a single trapped $^{138}$Ba$^+$ ion, to near infrared wavelengths for reduced network transmission losses and improved quantum networking capabilities. This work is the first-ever to frequency convert Ba$^+$ photons, being one of three nearly concurrent demonstrations of frequency converted photons from any trapped ion. After discussing our experimental techniques and laboratory setup, I first showcase our quantum frequency converters that convert ion-produced single photons to both 780 nm and 1534 nm for improved quantum networking range, whilst preserving the photons' quantum properties. Following this, I present two hybrid quantum networking experiments where we interact converted ion-photons near 780 nm with neutral $^{87}$Rb systems. In the initial experiment, we observe, for the first time, interactions between converted ion-photons and neutral Rb vapor via slow light. The following experiment is a multi-laboratory project where we observe Hong-Ou-Mandel interference between converted ion-photons and photons produced by an ensemble of neutral Rb atoms, where notably these sources are located in different buildings and are connected and synchronized via optical fiber. Finally, I describe an experiment in which we verify entanglement between a $^{138}$Ba$^+$ ion and converted photons near 780 nm. These results are critical steps towards producing remote entanglement between trapped ion and neutral atom quantum networking nodes. Motivated by these experimental results, I conclude by presenting a theoretical hybrid-networking architecture where neutral-atomic based nondestructive single photon measurement and storage can be integrated into a long-distance trapped-ion based quantum network to potentially improve remote entanglement rates

Low noise quantum frequency conversion of photons from a trapped barium ion to the telecom O-band

Trapped ions are one of the leading candidates for scalable and long-distance quantum networks because of their long qubit coherence time, high fidelity single- and two-qubit gates, and their ability to generate photons entangled with the qubit state of the ion. One method for creating ion-photon entanglement is to exploit optically transitions from the P_(1/2) to S_(1/2) levels, which naturally emit spin-photon entangled states. But these optical transitions typically lie in the ultra-violet and visible wavelength regimes. These wavelengths exhibit significant fiber-optic propagation loss, thereby limiting the transfer of quantum information to tens of meters. Quantum frequency conversion is essential to convert these photons to telecom wavelengths so that they can propagate over long distances in fiber-based networks, as well as for compatibility with the vast number of telecom-based opto-electronic components. Here, we generate O-band telecom photons via a low noise quantum frequency conversion scheme from photons emitted from the P_(1/2) to S_(1/2) dipole transition of a trapped barium ion. We use a two-stage quantum frequency conversion scheme to achieve a frequency shift of 375.4 THz between the input visible photon and the output telecom photon achieving a conversion efficiency of 11%. We attain a signal-to-background ratio of over 100 for the converted O-band telecom photon with background noise less than 15 counts/sec. These results are an important step toward achieving trapped ion quantum networks over long distances for distributed quantum computing and quantum communication

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven by a low-cost, low-power femtosecond laser oscillator. So far, all solid-state emitters solely exploit physics related to the electron charge and deliver emission spectra with substantial gaps. Here, we take advantage of the electron spin to realize a conceptually new terahertz source which relies on tailored fundamental spintronic and photonic phenomena in magnetic metal multilayers: ultrafast photo-induced spin currents, the inverse spin-Hall effect and a broadband Fabry-P\'erot resonance. Guided by an analytical model, such spintronic route offers unique possibilities for systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer generates ultrashort pulses fully covering the 1-to-30-THz range. Our novel source outperforms laser-oscillator-driven emitters such as ZnTe(110) crystals in terms of bandwidth, terahertz-field amplitude, flexibility, scalability and cost.Comment: 18 pages, 10 figure

Evaluating ozone depletion from very short-lived halocarbons

A new approach is needed for calculating the ozone depletion potential (ODP) of short-lived gases with mean lifetimes less than 100 days. Clearly, the ozone loss from such gases depends strongly on the location and season of emissions. It is proposed that delivery to the tropical tropopause is a surrogate for the amount of halogen entering the stratosphere. Thus 3-D global models, with accurate simulation of tropospheric chemistry and transport, can calculate the ODP specific to tropical sources (high) and high-latitude sources (low). The ODP of CH2BrCH2CH3  from this analysis ranges from 0.0002 to 0.06 depending on the location and season of emissions