Entangled photon experiments with a fast interferometric switchable beam splitter

In dieser experimentellen Arbeit wird ein polarisationsunabhäniger, schneller, interferometrisch schaltbarer Strahlteiler vorgestellt. Dieser besteht aus einem Mach-Zehnder Interferometer mit jeweils einer Pockels Zelle in jedem Arm. Die Pockels Zellen variieren die Phase des transmittierten Strahls indem sie eine Doppelbrechung in einem optischen Kristall mithilfe eines elektrischen Feldes induzieren. Dadurch kann das Verhältnis von Transmission und Reflexion des interferometrischen Stahlteilers geändert werden. Die Effizienz unseres Setups wurde mit Hilfe von verschränkten Photonen Paaren aus einer kollinearen SPDC Quelle getestet. Der Phasenschub Kontrast liegt bei 95% für Photonen in H/V und +/- polarisations Basis. Die Einschaltzeit der Pockels Zellen beträgt 6 ns bei einer Wiederholungsrate von 2.5 MHz. Weiters wurde der dieses Setup benutzt um ein delayed-choice Hong-Ou-Mandel Interferenz Experiment durchzuführen. Photonen einer kollinearen SPDC Quelle wurde zu den Eingängen des Interferometers geschickt. Die Pockels Zellen wurden von einem Quanten Zufallszahlen Generator gesteuert welcher sich in 40 m Entfernung von unserem Labor befand. Wir betrachteten die Koinzidenzen zwischen den beiden Ausgängen des Interferometers in Kombination mit dem ON/OFF Status der Pockels Zellen. Wenn die Pockels Zelle auf ON gestellt war und das Interferometer dadurch als Strahlteiler fungierte, konnten wir zwei-Photonen Interferenz sehen. Waren die Pockels Zellen jedoch OFF, wussten wir genau welches Eingangsphoton welchen Ausgang genommen hatte. In diesem Fall lässt sich keine Interferenz feststellen. Die Messergebnisse zeigen, dass Komplementarität zwischen Interferenz und "welcher-Weg" Information auch in einem zwei-Photonen Experiment gültig ist. Außerdem ist diese unabhängig von der raum-zeitlichen Anordnung zwischen dem Enstehungsprozess der Photonen und der Entscheidung welches Experiment durchgeführt wird.This experimental thesis shows a polarization independent ultrafast interferometric switchable beam splitter. It consits of a Mach-Zehnder interferometer with one Pockels Cell in each arm. By changing the voltage of the Pockels Cells we can tune the splitting ratio of the effective beam splitter. To test the performance of our setup we used heralded single photons from a collinear SPDC source. The phase-switching contrast is above 95% for H/V and +/- polarized photons and the rising time of the Pockels Cells is around 6 ns with a repetition rate of 2.5 MHz. We have also used this setup to perform a delayed-choice Hong-Ou-Mandel interference experiment. Both photons of a collinear SPDC source where sent to our interferometer. The Pockels Cells where triggered by a quantum random number generator which was located 40 m away from the photon source and the interferometer. We recorded the coincidence events between the outputs of the interferometer together with the ON/OFF status of the Pockels Cells. When the Pockels Cells where ON and the interferometer operated as a beam splitter, we observed two-photon interference. But when the Pockels Cells were OFF, we knew exactly which input photon was detected in which output mode and therefore no interference was resolved. This experiment shows that complementarity between interference and which-way information is also valid for the two-photon case. Furthermore this complementarity is also independent from the space time arrangement between the creation process of the photons and the decision which measurement to perform

Diffuse Sound Field Synthesis

Can uncorrelated surrounding sound sources be used to generate extended diffuse sound fields? By definition, targets are a constant sound pressure level, a vanishing average sound intensity, uncorrelated sound waves arriving isotropically from all directions. Does this require specific sources and geometries for surrounding 2D and 3D source layouts? As methods, we employ numeric simulations and undertake a series of calculations with uncorrelated circular/spherical source layouts, or such with infinite excess dimensions, and we point out relations to potential theory. Using a radial decay 1/r^b modified by the exponent b, the representation of the resulting fields with hypergeometric functions, Gegenbauer polynomials, and circular as well as spherical harmonics yields fruitful insights. In circular layouts, waves decaying by the exponent b=1/2 synthesize ideally extended, diffuse sound fields; spherical layouts do so with b=1. None of the layouts synthesizes a perfectly constant expected sound pressure level but its flatness is acceptable. Spherical t-designs describe optimal source layouts with well-described area of high diffuseness, and non-spherical, convex layouts can be improved by restoring isotropy or by mode matching for a maximally diffuse synthesis. Theory and simulation offer a basis for loudspeaker-based synthesis of diffuse sound fields and contribute physical reasons to recent psychoacoustic findings in spatial audio.Comment: 27 pages, 17 figures, submitted to acta acustica, including jan/feb 2024 upgrades while awaiting the review

A high-speed tunable beam splitter for feed-forward photonic quantum information processing

We realize quantum gates for path qubits with a high-speed, polarization-independent and tunable beam splitter. Two electro-optical modulators act in a Mach-Zehnder interferometer as high-speed phase shifters and rapidly tune its splitting ratio. We test its performance with heralded single photons, observing a polarization-independent interference contrast above 95%. The switching time is about 5.6 ns, and a maximal repetition rate is 2.5 MHz. We demonstrate tunable feed-forward operations of a single-qubit gate of path-encoded qubits and a two-qubit gate via measurement-induced interaction between two photons

Automated Identification and Quantification of Subretinal Fibrosis in Neovascular Age-Related Macular Degeneration Using Polarization-Sensitive OCT

Citation: Roberts P, Sugita M, Deák G, et al. Automated identification and quantification of subretinal fibrosis in neovascular age-related macular degeneration using polarization-sensitive OCT. Invest Ophthalmol Vis Sci

Experimental delayed-choice entanglement swapping

Motivated by the question, which kind of physical interactions and processes are needed for the production of quantum entanglement, Peres has put forward the radical idea of delayed-choice entanglement swapping. There, entanglement can be "produced a posteriori, after the entangled particles have been measured and may no longer exist". In this work we report the first realization of Peres' gedanken experiment. Using four photons, we can actively delay the choice of measurement-implemented via a high-speed tunable bipartite state analyzer and a quantum random number generator-on two of the photons into the time-like future of the registration of the other two photons. This effectively projects the two already registered photons onto one definite of two mutually exclusive quantum states in which either the photons are entangled (quantum correlations) or separable (classical correlations). This can also be viewed as "quantum steering into the past"

LICC: L-BLP25 in patients with colorectal carcinoma after curative resection of hepatic metastases--a randomized, placebo-controlled, multicenter, multinational, double-blinded phase II trial

Background: 15-20% of all patients initially diagnosed with colorectal cancer develop metastatic disease and surgical resection remains the only potentially curative treatment available. Current 5-year survival following R0-resection of liver metastases is 28-39%, but recurrence eventually occurs in up to 70%. To date, adjuvant chemotherapy has not improved clinical outcomes significantly. The primary objective of the ongoing LICC trial (L-BLP25 In Colorectal Cancer) is to determine whether L-BLP25, an active cancer immunotherapy, extends recurrence-free survival (RFS) time over placebo in colorectal cancer patients following R0/R1 resection of hepatic metastases. L-BLP25 targets MUC1 glycoprotein, which is highly expressed in hepatic metastases from colorectal cancer. In a phase IIB trial, L-BLP25 has shown acceptable tolerability and a trend towards longer survival in patients with stage IIIB locoregional NSCLC. Methods: This is a multinational, phase II, multicenter, randomized, double-blind, placebo-controlled trial with a sample size of 159 patients from 20 centers in 3 countries. Patients with stage IV colorectal adenocarcinoma limited to liver metastases are included. Following curative-intent complete resection of the primary tumor and of all synchronous/metachronous metastases, eligible patients are randomized 2:1 to receive either L-BLP25 or placebo. Those allocated to L-BLP25 receive a single dose of 300 mg/m2 cyclophosphamide (CP) 3 days before first L-BLP25 dose, then primary treatment with s.c. L-BLP25 930 mug once weekly for 8 weeks, followed by s.c. L-BLP25 930 mug maintenance doses at 6-week (years 1&2) and 12-week (year 3) intervals unless recurrence occurs. In the control arm, CP is replaced by saline solution and L-BLP25 by placebo. Primary endpoint is the comparison of recurrence-free survival (RFS) time between groups. Secondary endpoints are overall survival (OS) time, safety, tolerability, RFS/OS in MUC-1 positive cancers. Exploratory immune response analyses are planned. The primary endpoint will be assessed in Q3 2016. Follow-up will end Q3 2017. Interim analyses are not planned. Discussion: The design and implementation of such a vaccination study in colorectal cancer is feasible. The study will provide recurrence-free and overall survival rates of groups in an unbiased fashion. Trial Registration EudraCT Number 2011-000218-2

Rise and Fall of an Anti-MUC1 Specific Antibody

So far, human antibodies with good affinity and specificity for MUC1, a transmembrane protein overexpressed on breast cancers and ovarian carcinomas, and thus a promising target for therapy, were very difficult to generate.A human scFv antibody was isolated from an immune library derived from breast cancer patients immunised with MUC1. The anti-MUC1 scFv reacted with tumour cells in more than 80% of 228 tissue sections of mamma carcinoma samples, while showing very low reactivity with a large panel of non-tumour tissues. By mutagenesis and phage display, affinity of scFvs was increased up to 500fold to 5,7×10(-10) M. Half-life in serum was improved from below 1 day to more than 4 weeks and was correlated with the dimerisation tendency of the individual scFvs. The scFv bound to T47D and MCF-7 mammalian cancer cell lines were recloned into the scFv-Fc and IgG format resulting in decrease of affinity of one binder. The IgG variants with the highest affinity were tested in mouse xenograft models using MCF-7 and OVCAR tumour cells. However, the experiments showed no significant decrease in tumour growth or increase in the survival rates. To study the reasons for the failure of the xenograft experiments, ADCC was analysed in vitro using MCF-7 and OVCAR3 target cells, revealing a low ADCC, possibly due to internalisation, as detected for MCF-7 cells.Antibody phage display starting with immune libraries and followed by affinity maturation is a powerful strategy to generate high affinity human antibodies to difficult targets, in this case shown by the creation of a highly specific antibody with subnanomolar affinity to a very small epitope consisting of four amino acids. Despite these "best in class" binding parameters, the therapeutic success of this antibody was prevented by the target biology

Entwurf eines digitalen Signalverarbeitungssystems basierend auf dem Mikrocontrollerboard STM32F4discovery

eingereicht von Stefan Zotter, BScKurzfassungen in deutscher und englischer SpracheUniversität Linz, Masterarbeit, 2016(VLID)99744