Soliton Squeezing in a Mach-Zehnder Fiber Interferometer

A new scheme for generating amplitude squeezed light by means of soliton self-phase modulation is experimentally demonstrated. By injecting 180-fs pulses into an equivalent Mach-Zehnder fiber interferometer, a maximum noise reduction of $4.4 \pm 0.3$ dB is obtained ($6.3 \pm 0.6$ dB when corrected for losses). The dependence of noise reduction on the interferometer splitting ratio and fiber length is studied in detail.Comment: 5 pages, 4 figure

Generation and manipulation of squeezed states of light in optical networks for quantum communication and computation

We analyze a fiber-optic component which could find multiple uses in novel information-processing systems utilizing squeezed states of light. Our approach is based on the phenomenon of photon-number squeezing of soliton noise after the soliton has propagated through a nonlinear optical fiber. Applications of this component in optical networks for quantum computation and quantum cryptography are discussed.Comment: 12 pages, 2 figures; submitted to Journal of Optics

Bichromatic Local Oscillator for Detection of Two-Mode Squeezed States of Light

We present a new technique for the detection of two-mode squeezed states of light that allows for a simple characterization of these quantum states. The usual detection scheme, based on heterodyne measurements, requires the use of a local oscillator with a frequency equal to the mean of the frequencies of the two modes of the squeezed field. As a result, unless the two modes are close in frequency, a high-frequency shot-noise-limited detection system is needed. We propose the use of a bichromatic field as the local oscillator in the heterodyne measurements. By the proper selection of the frequencies of the bichromatic field, it is possible to arbitrarily select the frequency around which the squeezing information is located, thus making it possible to use a low-bandwidth detection system and to move away from any excess noise present in the system.Comment: 11 pages, 3 figure

About the possibility to measure the circular polarization of high-energy photon in reaction γ + e⁻ → e⁺ + e⁻ + e⁻

Two possibilities of the measuring high-energy photon circular polarization by means of the process γ + e⁻ → e⁺ + e⁻ + e⁻ are investigated. The first one is connected with the measurement of polarization asymmetry of the cross section when the initial electron beam is longitudinally polarized. The second possibility related with the measurement of the created-positron (or electron) polarization. Just this polarization does not decrease when the photon energy grows up and can be used for effective determination of the photon circular polarization degree.Проанализированы две возможности определения степени циркулярной поляризации высокоэнергетического фотона в процессе γ + e⁻ → e⁺ + e⁻ + e⁻. Первая связана с измерением поляризационной асимметрии сечения, когда начальный пучок электронов обладает продольной поляризацией. Вторая – с измерением поляризации образованного позитрона (или электрона). Показано, что в последнем случае поляризация не убывает с ростом энергии фотона и может быть использована для эффективного определения степени его циркулярной поляризации.Проаналізовано дві можливості визначити ступінь циркулярної поляризації фотона високої енергії у реакції γ + e⁻ → e⁺ + e⁻ + e⁻. Перша пов'язана із вимірюванням асиметрії перерізу, коли початковий пучок електронів має поздовжню поляризацію. Друга -- із вимірюванням поляризації утворюваного позитрона (чи електрона). Виявлено, що в останньому випадку поляризація не зменшується з ростом енергії фотона і може бути використана для ефективного визначення його циркулярної поляризації

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS): a 24-year clinical experience with 178 patients

BACKGROUND: Thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome (TTP-HUS) are related and uncommon disorders with a high fatality and complication rate if untreated. Plasma exchange therapy has been shown to produce high response rates and improve survival in patients with many forms of TTP-HUS. We performed a retrospective cohort study of 178 consecutively treated patients with TTP-HUS and analyzed whether clinical or laboratory characteristics could predict for important short- and long-term outcome measures. RESULTS: Overall 30-day mortality was 16% (n = 27). 171 patients (96%) received plasma exchange as the principal treatment, with a mean of 8 exchanges and a mean cumulative infused volume of 42 ± 71 L of fresh frozen plasma. The rate of complete response was 65% or 55% depending on whether this was defined by a platelet count of 100,000/μl or 150,000/μl, respectively. The rate of relapse was 18%. The Clinical Severity Score did not predict for 30-day mortality or relapse. The time to complete response did not predict for relapse. Renal insufficiency at presentation was associated with a decreased risk of relapse, with each unit increase in serum creatinine associated with a 40% decreased odds of relapse. 72% of our cohort had an idiopathic TTP-sporadic HUS, while 17% had an underlying cancer, received a solid organ transplant or were treated with a mitomycin-based therapy. The estimated overall 5-year survival was 55% and was significantly better in those without serious underlying conditions. CONCLUSION: Plasma exchange therapy produced both high response and survival rates in this large cohort of patients with TTP-HUS. The Clinical Severity Score did not predict for 30-day mortality or relapse, contrary to our previous findings. Interestingly, the presence of renal insufficiency was associated with a decreased risk of relapse. The most important predictor of mortality was the presence or absence of a serious underlying disorder

Spectral stability of nonlinear waves in KdV-type evolution equations

This paper concerns spectral stability of nonlinear waves in KdV-type evolution equations. The relevant eigenvalue problem is defined by the composition of an unbounded self-adjoint operator with a finite number of negative eigenvalues and an unbounded non-invertible symplectic operator $\partial_x$. The instability index theorem is proven under a generic assumption on the self-adjoint operator both in the case of solitary waves and periodic waves. This result is reviewed in the context of other recent results on spectral stability of nonlinear waves in KdV-type evolution equations.Comment: 15 pages, no figure

Partitioning optical solitons for generating entangled light beams

It is shown that bipartition of optical solitons can be used to generate entangled light beams. The achievable amount of entanglement can be substantially larger for N-bound solitons N=2,3 than for the fundamental soliton (N=1). An analysis of the mode structure of the entangled beams shows that just N modes are essentially entangled. In particular, partitioning of the fundamental soliton effectively produces 2-mode squeezed light.Comment: 5 pages, 3 PS figure

Linac failure diagnostics

The data processing subroutine from 60 discrete detectors is developed for the operating control system [1] of the technological linac. It uses a dialogue regime of work. This subroutine allows us to find a basic cause of linac failures in certain circuit, as well as the site of fault. Recommendations for repair are also given

Nonclassical correlations in damped quantum solitons

Using cumulant expansion in Gaussian approximation, the internal quantum statistics of damped soliton-like pulses in Kerr media are studied numerically, considering both narrow and finite bandwidth spectral pulse components. It is shown that the sub-Poissonian statistics can be enhanced, under certain circumstances, by absorption, which damps out some destructive interferences. Further, it is shown that both the photon-number correlation and the correlation of the photon-number variance between different pulse components can be highly nonclassical even for an absorbing fiber. Optimum frequency windows are determined in order to realize strong nonclassical behavior, which offers novel possibilities of using solitons in optical fibers as a source of nonclassically correlated light beams.Comment: 15 pages, 11 PS figures (color