Granular aluminium nanojunction fluxonium qubit.

Mesoscopic Josephson junctions, consisting of overlapping superconducting electrodes separated by a nanometre-thin oxide layer, provide a precious source of nonlinearity for superconducting quantum circuits. Here we show that in a fluxonium qubit, the role of the Josephson junction can also be played by a lithographically defined, self-structured granular aluminium nanojunction: a superconductor-insulator-superconductor Josephson junction obtained in a single-layer, zero-angle evaporation. The measured spectrum of the resulting qubit, which we nickname gralmonium, is indistinguishable from that of a standard fluxonium. Remarkably, the lack of a mesoscopic parallel plate capacitor gives rise to an intrinsically large granular aluminium nanojunction charging energy in the range of tens of gigahertz, comparable to its Josephson energy. We measure coherence times in the microsecond range and we observe spontaneous jumps of the value of the Josephson energy on timescales from milliseconds to days, which offers a powerful diagnostics tool for microscopic defects in superconducting materials.

Reducing the impact of radioactivity on quantum circuits in a deep-underground facility.

As quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor thirty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware.

Circuit quantum electrodynamics of granular aluminum resonators.

Granular aluminum (grAl) is a promising high kinetic inductance material for detectors, amplifiers, and qubits. Here we model the grAl structure, consisting of pure aluminum grains separated by thin aluminum oxide barriers, as a network of Josephson junctions, and we calculate the dispersion relation and nonlinearity (self-Kerr and cross-Kerr coefficients). To experimentally study the electrodynamics of grAl thin films, we measure microwave resonators with open-boundary conditions and test the theoretical predictions in two limits. For low frequencies, we use standard microwave reflection measurements in a low-loss environment. The measured low-frequency modes are in agreement with our dispersion relation model, and we observe self-Kerr coefficients within an order of magnitude from our calculation starting from the grAl microstructure. Using a high-frequency setup, we measure the plasma frequency of the film around 70 GHz, in agreement with the analytical prediction.

Quantum engineering. Confining the state of light to a quantum manifold by engineered two-photon loss.

Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. This notion can be generalized to the confinement of a system into a manifold of quantum states, consisting of all coherent superpositions of multiple stable steady states. We have confined the state of a superconducting resonator to the quantum manifold spanned by two coherent states of opposite phases and have observed a Schrödinger cat state spontaneously squeeze out of vacuum before decaying into a classical mixture. This experiment points toward robustly encoding quantum information in multidimensional steady-state manifolds.

Non-Poissonian quantum jumps of a fluxonium qubit due to quasiparticle excitations.

As the energy relaxation time of superconducting qubits steadily improves, nonequilibrium quasiparticle excitations above the superconducting gap emerge as an increasingly relevant limit for qubit coherence. We measure fluctuations in the number of quasiparticle excitations by continuously monitoring the spontaneous quantum jumps between the states of a fluxonium qubit, in conditions where relaxation is dominated by quasiparticle loss. Resolution on the scale of a single quasiparticle is obtained by performing quantum nondemolition projective measurements within a time interval much shorter than T1, using a quantum-limited amplifier (Josephson parametric converter). The quantum jump statistics switches between the expected Poisson distribution and a non-Poissonian one, indicating large relative fluctuations in the quasiparticle population, on time scales varying from seconds to hours. This dynamics can be modified controllably by injecting quasiparticles or by seeding quasiparticle-trapping vortices by cooling down in a magnetic field.

Measurement and control of quasiparticle dynamics in a superconducting qubit.

Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic fields to protect the integrity of the superconductivity. Here we show vortices can improve the performance of superconducting qubits by reducing the lifetimes of detrimental single-electron-like excitations known as quasiparticles. Using a contactless injection technique with unprecedented dynamic range, we quantitatively distinguish between recombination and trapping mechanisms in controlling the dynamics of residual quasiparticle, and show quantized changes in quasiparticle trapping rate because of individual vortices. These results highlight the prominent role of quasiparticle trapping in future development of superconducting qubits, and provide a powerful characterization tool along the way.

Oral surgery: part 2. Endodontic surgery.

In the past, the interaction between dentoalveolar surgery and restorative dentistry has been limited to the removal of teeth with pulp and/or periradicular disease or those that were unrestorable. However, with the increasing dental awareness of the population and the retention of teeth into later life, the interaction between dentoalveolar surgery and restorative dentistry is becoming a fundamental aspect of clinical practice. Indeed, endodontic and implant surgery are core activities that facilitate the retention of a functional dentition.

Demonstrating a driven reset protocol for a superconducting qubit.

Qubit reset is crucial at the start of and during quantum information algorithms. We present the experimental demonstration of a practical method to force qubits into their ground state, based on driving appropriate qubit and cavity transitions. Our protocol, called the double drive reset of population, is tested on a superconducting transmon qubit in a three-dimensional cavity. Using a new method for measuring population, we show that we can prepare the ground state with a fidelity of at least 99.5% in less than 3 µs; faster times and higher fidelity are predicted upon parameter optimization.

Type 2 diabetes mellitus is associated with an imbalance in circulating endothelial and smooth muscle progenitor cell numbers.

AIMS/HYPOTHESIS: Individuals with type 2 diabetes mellitus have increased rates of macrovascular disease (MVD). Endothelial progenitor cells (EPCs), circulating angiogenic cells (CACs) and smooth muscle progenitor cells (SMPCs) are suggested to play a role in the pathogenesis of MVD. The relationship between vasoregenerative EPCs or CACs and damaging SMPCs and the development of accelerated MVD in diabetes is still unknown. We tried to elucidate whether EPC, CAC and SMPC numbers and differentiation capacities in vitro differ in patients with and without diabetes or MVD. METHODS: Peripheral blood was obtained from individuals with and without diabetes and MVD (coronary or peripheral artery disease). EPC and SMPC numbers were determined with flow cytometry. Furthermore, CAC and SMPC numbers were quantified after in vitro culture. Their in vitro differentiation capacity was investigated with real-time RT-PCR and quantitative immunofluorescence. RESULTS: In diabetic patients both EPC and CAC levels were reduced (1.3-fold [p < 0.05] and 1.5-fold [p < 0.05], respectively). CAC outgrowth from diabetic patients with MVD was reduced 1.5-fold compared with diabetic patients without MVD (p < 0.05). SMPC levels were similar between diabetic patients and healthy controls. The CAC/SMPC ratio of in vitro cultured progenitor cells was reduced 2.3-fold in samples from diabetic patients (p < 0.001). The differentiation capacity of CACs and SMPCs in vitro remained similar independently of diabetes or MVD. CONCLUSIONS/INTERPRETATION: The ratio between EPCs or CACs and SMPCs is disturbed in type 2 diabetes in favour of SMPCs. This may translate into reduced vascular repair capacity, thereby promoting MVD in type 2 diabetes.

Coherent frequency conversion in a superconducting artificial atom with two internal degrees of freedom.

By adding a large inductance in a dc-SQUID phase qubit loop, one decouples the junctions' dynamics and creates a superconducting artificial atom with two internal degrees of freedom. In addition to the usual symmetric plasma mode (s mode) which gives rise to the phase qubit, an antisymmetric mode (a mode) appears. These two modes can be described by two anharmonic oscillators with eigenstates |ns> and |na> for the s and a mode, respectively. We show that a strong nonlinear coupling between the modes leads to a large energy splitting between states |0s,1a> and |2s,0a>. Finally, coherent frequency conversion is observed via free oscillations between the states |0s,1a> and |2s,0a>.

[Homunculus: Fetiform teratoma]. / Homunculus: Fetiform teratoma.

The term homunculus is a rare form of ovarian teratoma, highly differentiated that resembles a malformed fetus. Very few cases are reported in the literature. We present the clinical, pathological and imaging of this tumor type.

[Secondary cataract treatment with laser YAG-ND]. / Tratamentul cataractei secundare cu laser YAG-ND.

The purpose of the study is to present the favorable results of YAG: Nd laser capsulotomy for the treatment of secondary opacification of the posterior capsule, in our department. A 3 years retrospective study was performed. For 1440 cataract operations, most of them extracapsular extractions with PMMA IOL placed in the posterior chamber (ciliary sulcus or capsular bag), 285 laser capsulotomies were done. The results are presented statistically, including sex and age distribution, type of cataract surgery and implant, treatment protocol (number of sessions, number of impulses per session, energy per impulse) and complications. The frequency of secondary capsular opacification in our study is 19.78%. It is most important in the age group 60-70 years, where the surgery for cataract is performed more often. Capsulotomy was done after extracapsular extraction with IOL placed in the posterior chamber, but especially after extracapsular extraction without implant placement or with complications that have permitted only the use of an anterior chamber implant. Capsulotomy is performed in only one session in 88% of the cases. The energy per impulse is usually 3-5 mJ and the mean number of impulses per session is 10-30. There are few complications: transient elevation of intraocular pressure in 14.73%, discrete laser marks on the implant in 8.77% and moderate iritis in 1% of the cases. YAG: Nd laser capsulotomy appears to be a safe and efficient method of treating secondary cataract; it improved visual acuity in all cases, if different ocular pathology had not influenced it.

[Incidence of ocular trauma in Clinical Hospital Oradea between 1997-1999]. / Incidenta traumatismelor oculare în spitalul clinic de oftalmologie oradea în perioada 1997-1999.

The purpose of the study is to analyse the great number of ocular injuries which were diagnosed and treated in the out-patients clinic or in the hospital in 1997-1999. Ocular trauma seems to be related to the working place or the main activities of the patients, such as agriculture or housekeeping. Ocular injuries in children are significant as number and prognosis. Blunt trauma, ocular perforations, ocular foreign bodies and burns were studied separately for children, housekeepers, unemployed, working and retired people. Due to their number and complexity, ocular trauma represent a very important part in the activity of an ophthalmology department. The conclusion of the study is the number of ocular injuries decreased over the years because of the reduced industrial activity in our town. Similar ocular injuries in retired and working people suggest that retired people are still active. The prognosis of ocular trauma is better if the patients come early to be seen by the specialist, if the treatment is adequate and if the department has a proper equipment for advanced surgery techniques.

[A myopia study of glaucoma patients following pilocarpine instillation]. / Studiul miopiei la bolnavii cu glaucom dupa instilare de pilocarpina.

AIM: Our research studies transitory myopia induced by Pilocarpine treatment in glaucoma patients. MATERIAL AND METHODS: 48 patients with open angle glaucoma were selected, visual acuity and refraction were measured before and after the instillation of Pilocarpine 2%, for two hours. Induced myopia was compared for different ages and it was established the influence of Timolol and Acetazolamide administered in the same time. RESULTS: Transitory myopia is important in young patients, reduced after 50 years and absent after 70 years. Acetazolamide increases myopia, Timolol has no effect on refraction. CONCLUSIONS: The study confirms the unpleasant effect of Pilocarpine and suggests not performing refractometry in the first two hours after the instillation of the drug.

[Effect of the microclimate of salt mines on T- and B-lymphocyte function in bronchial asthma patients]. / Vliianie mikroklimata solianykh shakht na sostoianie T- i B-limfotsitov u bol'nykh bronkhial'noi astmoi.

A study of 55 patients with bronchial asthma revealed a reduction of the relative number of T-lymphocytes and their IgA content. The changes were most pronounced in patients during the phase of unstable remission of the disease. Disorders of the T- and B-system of lymphocytes were associated with an increased number of cortisol-resistant lymphocytes. After a course of speleotherapy one could observe an increase of the number of T-lymphocytes and their functional activity, normalization of the number of B-lymphocytes, increase of the level of IgA, reduction of the IgM content and of the relative content of cortisol-resistant lymphocytes fraction.

Effects of zinc-aspartate and zinc-glycinate in healthy rats and on reserpine-induced gastric lesions.

Experimental studies performed on 227 rats showed that Zn-aspartate and Zn-glycinate administered ip lowered the incidence, number, and severity of the reserpine-induced gastric lesions ensuring significant protection indices. Histochemical methods revealed increased amount of mucosal glycoproteins. The activity of dehydrogenases involved in energy metabolism that modulates acid secretion in the parietal cells was depressed. RNA content in the chief cells, as premises of pepsinogen synthesis, was decreased. ATPase reaction in the periglandular capillaries was uniform and stronger, showing an improvement of gastric mucosal microcirculation. Since these histochemical changes were also noted in healthy rats receiving Zn salts, it might be suggested that they are not the mere expression of an anti-ulcer protective effect of zinc, but rather reflect its mechanism of action, relating to the complex metabolic events induced by the trace element. Our results are in agreement with those previously reported concerning the noxious influence of Zn depletion, the accelerated healing of peptic ulcer patients after Zn treatment, and the protective effect of Zn against ulcerogenesis in several experimental models involving different pathomechanisms.