Efficient simulation of Gottesman-Kitaev-Preskill states with Gaussian circuits

We study the classical simulatability of Gottesman-Kitaev-Preskill (GKP) states in combination with arbitrary displacements, a large set of symplectic operations and homodyne measurements. For these types of circuits, neither continuous-variable theorems based on the non-negativity of quasi-probability distributions nor discrete-variable theorems such as the Gottesman-Knill theorem can be employed to assess the simulatability. We first develop a method to evaluate the probability density function corresponding to measuring a single GKP state in the position basis following arbitrary squeezing and a large set of rotations. This method involves evaluating a transformed Jacobi theta function using techniques from analytic number theory. We then use this result to identify two large classes of multimode circuits which are classically efficiently simulatable and are not contained by the GKP encoded Clifford group. Our results extend the set of circuits previously known to be classically efficiently simulatable

Sufficient condition for universal quantum computation using bosonic circuits

We present a new method for quantifying the resourcefulness of continuous-variable states in the context of promoting otherwise simulatable circuits to universality. The simulatable, albeit non-Gaussian, circuits that we consider are composed of Gottesman-Kitaev-Preskill states, Gaussian operations, and homodyne measurements. We first introduce a general framework for mapping a continuous-variable state into a qubit state. We then express existing maps in this framework, including the modular subsystem decomposition and stabilizer subsystem decomposition. Combining these results with existing results in discrete-variable quantum computation provides a sufficient condition for achieving universal quantum computation. These results also allow us to demonstrate that for states symmetric in the position representation, the modular subsystem decomposition can be interpreted in terms of resourceless (simulatable) operations - i.e., included in the class of Gaussian circuits with input stabilizer Gottesman-Kitaev-Preskill states. Therefore, the modular subsystem decomposition is an operationally relevant mapping to analyze the logical content of realistic Gottesman-Kitaev-Preskill states, among other states.Comment: 30 pages, 13 figure

Gaussian conversion protocol for heralded generation of qunaught states

In the field of fault-tolerant quantum computing, continuous-variable systems can be utilized to protect quantum information from noise through the use of bosonic codes. These codes map qubit-type quantum information onto the larger bosonic Hilbert space, and can be divided into two main categories: translational-symmetric codes, such as Gottesman-Kitaev-Preskill (GKP) codes, and rotational-symmetric codes, including cat and binomial codes. The relationship between these families of codes has not yet been fully understood. We present an iterative protocol for converting between two instances of these codes GKP qunaught states and four-foldsymmetric binomial states corresponding to a zero-logical encoded qubit - using only Gaussian operations. This conversion demonstrates the potential for universality of binomial states for all-Gaussian quantum computation and provides a new method for the heraladed preparation of GKP states. Through numerical simulation, we obtain GKP qunaught states with a fidelity of over 98% and a probability of approximately 3.14%, after only two steps of our iterative protocol, though higher fidelities can be achieved with additional iterations at the cost of lower success probabilities.Comment: 10 page

Universal Gate Set for Continuous-Variable Quantum Computation with Microwave Circuits

We provide an explicit construction of a universal gate set for continuous-variable quantum computation with microwave circuits. Such a universal set has been first proposed in quantum-optical setups, but its experimental implementation has remained elusive in that domain due to the difficulties in engineering strong nonlinearities. Here, we show that a realistic microwave architecture allows to overcome this difficulty. As an application, we show that this architecture allows to generate a cubic phase state with an experimentally feasible procedure. This work highlights a practical advantage of microwave circuits with respect to optical systems for the purpose of engineering non-Gaussian states, and opens the quest for continuous-variable algorithms based on a few repetitions of elementary gates from the continuous-variable universal set.Comment: 6+6 pages, 2 figure

Bayesian evaluation of the accuracy of a thoracic auscultation scoring system in dairy calves with bronchopneumonia using a standard lung sound nomenclature

BackgroundAlthough thoracic auscultation (AUSC) in calves is quick and easy to perform, the definition of lung sounds is highly variable and leads to poor to moderate accuracy in diagnosing bronchopneumonia (BP). Hypothesis/ObjectivesEvaluate the diagnostic accuracy of an AUSC scoring system based on a standard lung sound nomenclature at different cut-off values, accounting for the absence of a gold standard test for BP diagnosis. AnimalsThree hundred thirty-one calves. MethodsWe considered the following pathological lung sounds: increased breath sounds (score 1), wheezes and crackles (score 2), increased bronchial sounds (score 3), and pleural friction rubs (score 4). Thoracic auscultation was categorized as AUSC1 (positive calves for scores & GE;1), AUSC2 (positive calves for scores & GE;2), and AUSC3 (positive calves for scores & GE;3). The accuracy of AUSC categorizations was determined using 3 imperfect diagnostic tests with a Bayesian latent class model and sensitivity analysis (informative vs weakly informative vs noninformative priors and with vs without covariance between ultrasound and clinical scoring). ResultsBased on the priors used, the sensitivity (95% Bayesian confidence interval [BCI]) of AUSC1 ranged from 0.89 (0.80-0.97) to 0.95 (0.86-0.99), with a specificity (95% BCI) of 0.54 (0.45-0.71) to 0.60 (0.47-0.94). Removing increased breath sounds from the categorizations resulted in increased specificity (ranging between 0.97 [0.93-0.99] and 0.98 [0.94-0.99] for AUSC3) at the cost of decreased sensitivity (0.66 [0.54-0.78] to 0.81 [0.65-0.97]). Conclusions and Clinical ImportanceA standardized definition of lung sounds improved AUSC accuracy for BP diagnosis in calves

A virtual reality study on postretrieval extinction of smoking memory reconsolidation in smokers

Exposure to smoking-related stimuli may induce the reconsolidation of smoking-related memories in smokers. Research has proposed that extinction applied after the retrieval of a smoking memory may inhibit reconsolidation and prevent craving. The aim of this study was to test the effect of postretrieval extinction (PRE) on the reconsolidation of smoking memory by using a virtual reality (VR) simulation in smokers. On the day 1 session, the study exposed 46 smokers to a neutral and then to a smoking VR scenario under a fixed-block protocol. On day 2, the study randomized participants into three groups (G) and exposed them to a 15-s VR immersion in smoking (G1, G3) or neutral (G2) scenario for memory retrieval. After 15 min, the study exposed G1 and G2 to a VR PRE during the temporal window of memory vulnerability, whereas the study exposed G3 to extinction immediately after retrieval. On day 3, the study exposed all groups to neutral and smoking scenarios similar to day 1. All groups significantly increased craving for cigarettes after exposure to the smoking scenario on day 1 (p 0.01). On day 3, VR PRE after a 15-second VR smoking memory retrieval was able to inhibit reconsolidation in G1, but not in G3 exposed to PRE before the window of vulnerability, or in G2 not exposed to the smoking memory retrieval. These findings show the superiority of VR PRE after smoking memory retrieval compared to a standard extinction procedure

Virtual Reality for Neuroarchitecture: Cue Reactivity in Built Spaces

Domestic and urban environments are associated to our life experiences and behaviors. These environments may acquire an emotional and motivational value and, in turn, shape our behaviors. Although there is a well-established knowledge of the effects of built space features on perception, feelings, and affective responses (Ulrich, 1991), only a limited attention has been however paid to physical space-induced motivated behaviors. There is still a strong attitude to consider the control of motivated behaviors as a matter of individual desires, free will, moral choices, executive control, etc.—and not as the interaction between environment and personality, genetics, and brain mechanisms. Recently, there has been a convergent agreement from architects, designers, psychologists, and neuroscientists about the multifactorial nature of the reciprocal interaction between humans and built space, and how it could impact on well-being psychological distress and risky behaviors (Sternberg, 2009). The emerging interdisciplinary field of “neuroarchitecture” developed conceptual paradigms and empirical frameworks based on the interaction between brain and built spaces (see Academy of Neuroscience for Architecture; www.anfarch.org). Within this framework, we would like to propose the “Cue Reactivity” phenomenon as a paradigmatic example of such as interaction. Cue reactivity (C-R) is the adaptive response to salient information in the environment (Niaura et al., 1988). Salient information is that associated to drugs, sex, palatable food, and to a variety of natural and non-natural rewards (such as gambling, shopping, etc.). Drug C-R manifests itself as an array of responses to stimuli previously associated to drug effect. The detrimental consequence of C-R is relapse to drug-seeking and drug-taking (Rohsenow et al., 1991). On the other hand, C-R is an evolutionary phenotype of the interaction with the environment: in fact, spatial context rich of reward-related cues may stimulate both positive and risky motivated behaviors. In this Opinion paper, we will show that identification and design of specific physical space features may affect mental health, and that indoor and furniture of drinking venues are associated to alcohol use. Based on what we know about C-R, and on the effects of built spaces on psychological and behavioral processes, we think that more research is now possible to plan and design research-based “C-R-free situations.” For instance, investigations on outdoor and indoor features associated to C-R may help to develop “motivational safer built environments.” The complexity of real world investigations is not however easily modeled in the laboratory, but technologies like virtual reality may offer the possibility to increase subject's presence in a spatial context simulation and, in the meantime, the control of the experimental parameters (García-Rodríguez et al., 2012). For these reasons, we propose virtual reality as a methodological approach in-between naturalistic and experimental lab setting for a better understanding of built space features affecting C-R.The “5per mille 2012” research grant by the Italian Cancer League (Lega Italiana Lotta per i Tumori, LILT) supported the study (PI: CC) and research grant for GB. LILT also supported CC and SF with educational grants

Generation of induced pluripotent stem cells (iPSCs) from patient with Cri du Chat Syndrome

Abstract The Cri du Chat Syndrome (CdCS) is a genetic disease resulting from variable size deletion occurring on the short arm of chromosome 5. The main clinical features are a high-pitched monochromatic cry, microcephaly, severe psychomotor and mental retardation with characteristics of autism spectrum disorders such as hand flapping, obsessive attachments to objects, twirling objects, repetitive movements, and rocking. We reprogrammed to pluripotency peripheral blood mononuclear cells derived from a patient carrying large deletion on the short arm of chromosome 5, using a commercially available non-integrating expression system. The iPSCs expressed pluripotency markers and differentiated in the three embryonic germ layers

From TiO2 and Graphite to Graphene doped TiO2 for visible light photocatalytic degradation of refractory dye.

Graphene production is an ongoing challenge for large-scale applications. Many processes are used to produce graphene 1. Top-down method such as the exfoliation of graphite powder in liquid phase by sonication is a promising route to create high quality graphene in great quantity due to its simplicity, its versatility and its low-cost 2. Graphene with the thickness of a single carbon atom owns unique physical and chemical properties like large surface area, highly flexible structure, high electrical and thermal conductivity and high chemical stability 3. With these properties, graphene is an attractive material in applications that require a fast electron transfer, such as photocatalysis. In fact, graphene based semiconductor nanocomposites are considered as good photocatalyst for pollutant degradation 4. Graphene is an ideal nanomaterial for doping TiO2 because the formation of Ti-O-C bonds extend the visible light absorption of TiO2. Furthermore, electrons are easily transported from TiO2 to graphene nano-sheets and the electron-hole recombination is reduced; this is enhances the oxidative reactivity 5. In this work, graphene doped TiO2 nanocomposite was used as photocatalytic materials for the Alizarin Red S degradation in water solutions. Graphene dispersions were prepared by liquid-phase exfoliation of graphite in the presence of a non-ionic surfactant, Triton X-100. The obtained graphene dispersion was characterized by X-Ray Diffraction, Dynamic Light Scattering and UV-Visible spectroscopy and was subsequently used for the preparation of graphene doped-TiO2 photocatalyst. Graphene doped-TiO2 nanocomposites showed higher adsorption of Alizarin Red S on the catalyst surface and higher photocatalytic activity for its degradation under visible light irradiation, respect to those obtained with pure TiO2 6. References: 1) Dimiev, A. M.; Tour, J. M. ACS Nano, 2014, 8, 3060 - 3068. 2) Samorì, P. et al. Chemical Society Reviews, 2014, 43, 381 - 398. 3) Geim, A.K.; Novoselov, K. S. Nature Materials, 2007, 6, 183 - 191. 4) Khalid, N. R.; Hong, Z. et al. Current Applied Physics, 2013, 13, 659 - 663. 5) Li, F.; Cheng, H. M. et al. Advanced Functional Materials, 2011, 21, 1717 - 1722. 6) Giovannetti, R.; D’ Amato, C. A. et al. Scientific Reports, 2015, 5, 17801

Does the addition of a second daily session of hyperbaric oxygen therapy to intratympanic steroid influence the outcomes of sudden hearing loss? [L’aggiunta di una seconda sessione giornaliera di camera iperbarica al trattamento steroideo intratimpanico influenza i risultati terapeutici nella sordità improvvisa?]

The aim of this study is to investigate whether, in addition to intratympanic steroid therapy, additional hyperbaric oxygen therapy (HBOT) sessions per day (twice a day for 5 days) is more useful than one session per day for 10 days in patients affected by severe and profound idiopathic sudden sensorineural hearing loss (ISSNHL). A total of 55 patients affected by unilateral severe and profound ISSNHL were recruited. Two protocols were adopted. In the first, 27 patients (13 with profound and 14 with severe hearing loss) underwent one session of HBOT per day for 10 days, 6 days a week. An HBOT session comprised a period of 14 minutes air compression followed by 90 min at 2.4 atm absolute (ATA) followed by a decompression period of 15 min in oxygen. Patients breathed 100% oxygen through an appropriate mask checked for leaks. Patients were given 0.4 ml of 62.5 mg/ml of intratympanic prednisolone during the first three days of the protocol. In the second protocol, 28 patients (10 with profound and 18 with severe hearing loss) received 10 sessions of HBOT, twice a day for five days, 2.4 ATA 90 min 100% oxygen. The intratympanic injections of prednisolone were given between the two sessions of HBOT during the first three days of the protocol. Since there were no significant differences in hearing outcomes between the two protocols, the present study shows that the protocol of two sessions of HBOT per day is a valid treatment and equally effective as the one HBOT session per day, but with shorter treatment time