An optical transition-edge sensor with high energy resolution

Optical transition-edge sensors have shown energy resolution for resolving the number of incident photons at the telecommunication wavelength. Higher energy resolution is required for biological imaging and microscope spectroscopy. In this paper, we report on a Au/Ti (10/20 nm) bilayer TES that showed high energy resolution. This was achieved by lowering the critical temperature Tc to 115 mK and the resultant energy resolution was 67 meV full width at half maximum (FWHM) at 0.8 eV. When Tc was lowered to 115 mK, the theoretical resolution would scaled up to 30 meV FWHM, considering that the typical energy resolution of optical TESs is 150 meV and Tc is 300 mK. To investigate the gap between the theoretical expectation (30 meV) and the measured value (67 meV), we measured its complex impedance and current noise. We found excess Johnson noise in the TES and an excess Johnson term M was 1.5 at a bias point where the resistance was 10% of normal resistance. For reference, the TES was compared with a TES showing typical energy resolution (156 meV FWHM). We will discuss what improved the energy resolution and what might have been the limiting factor on it

Quantum receiver beyond the standard quantum limit of coherent optical communication

The most efficient modern optical communication is known as coherent communication and its standard quantum limit (SQL) is almost reachable with current technology. Though it has been predicted for a long time that this SQL could be overcome via quantum mechanically optimized receivers, such a performance has not been experimentally realized so far. Here we demonstrate the first unconditional evidence surpassing the SQL of coherent optical communication. We implement a quantum receiver with a simple linear optics configuration and achieve more than 90% of the total detection efficiency of the system. Such an efficient quantum receiver will provide a new way of extending the distance of amplification-free channels, as well as of realizing quantum information protocols based on coherent states and the loophole-free test of quantum mechanics.Comment: 5 pages, 3 figure

Timing jitter removers of photon detectors

Among various performances of photon detectors, the timing jitter is difficult to improve because of its trade-offs with other important performances such as detection efficiency. Such trade-offs have been an issue in applications, especially for high-purity non-Gaussian-state generation necessary in optical quantum computation. Here, we introduce a method using an external fast optical switch -- Timing Jitter Remover (TJR) -- whose time window limits the photon-detectable time of photon detectors and improve the timing jitter without sacrificing other performances. By using a TJR, we experimentally improve the timing jitter of a photon-number-resolving detector based on a transition edge sensor, from 50 ns to 10 ns. Using this improved detector, we generate one of important non-Gaussian states, a Schr\"{o}dinger cat state with Wigner negativity of -0.01, which cannot be observed without TJRs. TJRs would be the key technology for the realization of ultra-fast, fault-tolerant, universal optical quantum computer.Comment: 26 pages, 6 figure

Basement membrane assembly of the integrin α8β1 ligand nephronectin requires Fraser syndrome–associated proteins

Dysfunction of the basement membrane protein QBRICK provokes Fraser syndrome, which results in renal dysmorphogenesis, cryptophthalmos, syndactyly, and dystrophic epidermolysis bullosa through unknown mechanisms. Here, we show that integrin α8β1 binding to basement membranes was significantly impaired in Qbrick-null mice. This impaired integrin α8β1 binding was not a direct consequence of the loss of QBRICK, which itself is a ligand of integrin α8β1, because knock-in mice with a mutation in the integrin-binding site of QBRICK developed normally and do not exhibit any defects in integrin α8β1 binding. Instead, the loss of QBRICK significantly diminished the expression of nephronectin, an integrin α8β1 ligand necessary for renal development. In vivo, nephronectin associated with QBRICK and localized at the sublamina densa region, where QBRICK was also located. Collectively, these findings indicate that QBRICK facilitates the integrin α8β1–dependent interactions of cells with basement membranes by regulating the basement membrane assembly of nephronectin and explain why renal defects occur in Fraser syndrome.©2012 Kiyozumi et al. Originally published in the Journal of Cell Biology. https://doi.org/10.1083/jcb.20120306

McKeown esophagectomy for a thoracic esophageal carcinoma patient who has a history of definitive chemoradiotherapy for esophageal carcinoma and total pharyngolaryngectomy for hypopharyngeal cancer

Abstract A 64-year-old man, who had previously undergone definitive chemoradiotherapy (dCRT) and endoscopic resections for metachronous multiple esophageal squamous cell carcinoma (ESCC) and had also received total pharyngolaryngectomy (TPL) for hypopharyngeal cancer, was diagnosed with ESCC in the middle thoracic esophagus (cT3N0M0). Thoracoscopic McKeown esophagectomy was performed for the patient. Although the tumor was tightly adherent to the thoracic duct and both main bronchi, they were successfully mobilized. In order to maintain the blood supply to the trachea, we preserved the bilateral bronchial arteries and avoided prophylactic upper mediastinal lymph node dissection. Cervical end-to-side anastomosis between the jejunum and a gastric conduit was performed. Minor pneumothorax was managed conservatively, and the patient was discharged 44 days after the surgery. Overall, thoracoscopic McKeown esophagectomy was safely performed in a patient with a history of TPL and dCRT. Surgeons should be very careful to prevent tracheobronchial ischemia by optimizing the extent of lymph node dissection