Quantum leakage detection using a model-independent dimension witness

Users of quantum computers must be able to confirm they are indeed functioning as intended, even when the devices are remotely accessed. In particular, if the Hilbert space dimension of the components are not as advertised -- for instance if the qubits suffer leakage -- errors can ensue and protocols may be rendered insecure. We refine the method of delayed vectors, adapted from classical chaos theory to quantum systems, and apply it remotely on the IBMQ platform -- a quantum computer composed of transmon qubits. The method witnesses, in a model-independent fashion, dynamical signatures of higher-dimensional processes. We present evidence, under mild assumptions, that the IBMQ transmons suffer state leakage, with a $p$ value no larger than $5{\times}10^{-4}$ under a single qubit operation. We also estimate the number of shots necessary for revealing leakage in a two-qubit system.Comment: 11 pages, 5 figure

Institutional Arrangements: A Gate Towards Sustainable Land Use

Various common problems can be observed of the ongoing land management processes in Central and Eastern European (CEE) countries. The problems appear mainly because of conflicting legislation, performance of procedures, political unwillingness, lack of capacity of the local municipalities and other public administration, insufficiency of information and people participation, lack of skills of the professionals and in public administration. Source of all the mentioned problems is insufficient understanding of the institutional setting of the land management processes. The aim of this contribution is to introduce the reader to the theory of the institutional economics and discuss its importance for systematisation of both the regulatory framework, i.e. institutions – ‘rules of the game’ and the procedures in the fields of territorial planning and real property formation. This theory provides a vocabulary to describe the balance between the regulatory structures (public sector) and the market forces (private sector) that will allow controlled growth and will be perceived as of general economic and social well being to the populace. Thus, the paper is intended to activate and urge politicians, governmental authorities, non-governmental organizations, academic staff and managers of private firms. This contribution also can be seen as a source for further development of concepts for analysis of the observed problems. Hence combining the theory with appropriate methodology may suggest, how to deal with the stated various problems. Monographic descriptive method and logical analysis have been used in this contribution

Clinical trial of a new glass ionomer for an atraumatic restorative treatment technique in class I restorations placed in latvian school children

Objective: The aim of this study was to evaluate the performance of a new glass ionomer filling material (Chem-FlexTM) using the atraumatic restorative treatment (ART) approach in class I cavities in the permanent dentition of Latvian schoolchildren. Methods: A total of 63 fillings (40 test and 23 control) were placed using the ART technique in 41 schoolchildren in Riga at the Stomatology Institute of the Medical Academy of Latvia. These fillings were then blindly assessed after 2 years. Results: The complete success rate for both the test and the control material fillings were 92.5 and 94.9%, respectively. Conclusion: The new glass ionomer filling has shown a good performance in terms of retention, marginal failure and fractures in class I cavities.Peer reviewe

LATGOLA I VYROVA: AP REGIONA VOLŪDYS VUICEIŠONU LATVEJIS I IGAUNEJIS ŠKOLUOS I BĀRNUDUORZŪS

Pādejā laikā latgalīšu (i Latvejis vysumā) socialajā diskursā cieški monomys nūruodis iz tū, ka Igauneja asūte taida kai Baļtejis regiona „paraugvaļsteiba“. Daudzeji roksta, ka Latveja varātu puorjimt „lobū praktiku“ nu Igaunejis, kurei Baļtejis koņtekstā vysutuoļuok nūguojuse taiduos lītuos kai nūdūkļu saparāds, minimaluos olgys paceļšona, satiksmis sistemys reguliešona, birokratejis mazynuošona, vaļstiskuo sektora pakaļpīņu elektroniziešona i tt. Napreteņdādami iz itaidys saleidzynuošonys pamatu vysapjamūšu analizi, itymā referatā patēmēsim, voi vyrovīši (Dīnavydigaunejis regionaluos volūdys runuotuoji) varātu byut kaids naviņ paraugs latgalīšim vuiceibys atzarē, a taišni – regiona volūdys i kulturys vuiceišonā školuos i bārnuduorzūs. Samārojūt situaceju Latvejā i Igaunejā, redzīs, ka regiona volūdys vuiceišonā Igauneja eistyn tykuse tuoļuok kai Latveja. Tai, pīvadumam, vyrovīšu aba dīnavydigauņu literarū volūdu, aba „vyru-setu“ volūdu (t. i., igauņu volūdys dīnavydu variantu ar sovu seneju literaturys tradiceju) 2016/ 2017 godā kai prīškmatu vuica 17 Dīnavydigaunejis školuos, nu jūs 12 školuos vyrovīšu volūda i kultura irā fakuļtativs puļceņš, a 5 školuos – vuiceibu programys daļa (kai vīns nu izalosomūs prīškmatu). Kuruos nakuruos školuos vyrovīšu volūdys stuņdis agruokā voi vāluokā klasē puorīt vysi škoļnīki, a nazcik školuos vyrovīšu volūda jau suokta izlītuot taišni kai apvuiceibys volūda (jamā nūteik dorbvuiceibys i dzīduošonys stuņdis). Kas zeimojās iz bārnuduorzim, vyrovīši niule īdzeivynoj treju godu (2015–2018) projektu, kura ramuos 14 bārnuduorzūs (16 grupeņuos) div dīnys nedeļā audzynuotuojis vysu dīnu ar bārnim runoj vyrovīšu (dīnavydigauņu) volūdā, a palykušuos treis nedelis dīnys – vaļstiskuos igauņu volūdys formā. Regiona volūdys vuiceišona školuos i bārnuduorzūs breineigi nūteik i cytuos ES vaļsteibuos (Puolejā, Suomejā i tt.), tok Igauneju saleidzynuošonai izalasejom deļ juos geografiskuo tyvuma Latgolai i deļ leidzeiguos ar Latveju sociolingvistiskuos situacejis: - Igaunejā, taipoš kai Latvejā, irā lels krīvvolūdeigūs dzeivuotuoju procents, i deļtuo vaļsteiba, taipoš kai Latveja, beistās oficialai pīzeit regionaluos volūdys statusu (itamā zinē saleidzynuošonai nader, saceisim, Puoleja); - Igauneja, taipoš, kai Latveja, samārā nabogota vaļsteiba ar labtik aprūbežuotom vareibom finaņsēt vuiceibys sistemu (itamā zinē saleidzynuošonai nader, pīvadumam, Suomeja). Itymā referatā: - apsavērsim, kaidi faktori vadynoj regiona volūdys mudruoku īīšonu vuiceibys sistemā; - caur vuiceibys prizmu raudzeisim atsaceit iz vaicuojumu, deļkuo taids populars irā redzīņs, ka Igauneja „īt pa prīšku Latvejai“; - raudzeisim pasuokt diskuseju, kū Baļtejis vaļsteibys tei nu tuos varātu pasavuiceit, kab pyrmaškolys i školys vacuma bārnim byutu kū gods, tū leluokys vareibys oficialai vuiceitīs regiona volūdu

Learning-based quantum error mitigation

If NISQ-era quantum computers are to perform useful tasks, they will need to employ powerful error mitigation techniques. Quasi-probability methods can permit perfect error compensation at the cost of additional circuit executions, provided that the nature of the error model is fully understood and sufficiently local both spatially and temporally. Unfortunately these conditions are challenging to satisfy. Here we present a method by which the proper compensation strategy can instead be learned ab initio. Our training process uses multiple variants of the primary circuit where all non-Clifford gates are substituted with gates that are efficient to simulate classically. The process yields a configuration that is near-optimal versus noise in the real system with its non-Clifford gate set. Having presented a range of learning strategies, we demonstrate the power of the technique both with real quantum hardware (IBM devices) and exactly-emulated imperfect quantum computers. The systems suffer a range of noise severities and types, including spatially and temporally correlated variants. In all cases the protocol successfully adapts to the noise and mitigates it to a high degree.Comment: 28 pages, 19 figure

ON A MATHEMATICAL MODEL DESCRIBING OPTIMAL PROCESSING MECHANISM OF DISPERSED GRANULAR MATERIALS IN GRAVITATIONAL FLOW WITH HORIZONTAL OR INCLINED VIBRATING SIEVE CLASSIFYING SCREENS

The investigation of motion and gravitational processing of disperse granular materials is very important for solution of a wide spectrum of technological processes, including the chemical technology of treatment (with or without the decoration-compression procedure) of granular mineral fertilizers and their drying and sorting/separation by means of vibrating sieve classifying screens, in particular. In this work, we have used the apparatus of the theory of continuous media for the mathematical modelling of dynamics of disperse granular materials, and by this we assume that a property of these materials is the distribution of a solid granular component inside of them. The elaborated mathematical model is based on the volume conservation law for granular components, on the momentum conservation law, as well as on the equations for stress tensor in the granular mineral fertilizers and equations for description of the Coulomb granular mineral fertilizers

Mathematical Model of Friction Coefficient Determination for Lubricated Surfaces

This article reviews mathematical model for the determination of friction coefficient for lubricated surfaces which operate works at sliding friction pairs in boundary lubrication case. In the particular model an absolutely smooth ball and rough surface contact is viewed taking into account properties of the material, surface roughness parameters, lubricating material kinematic viscosity and density. The model refers to widely spread ball-on-disc type tribometer where ball is in the contacts with plane

Importance of data acquisition in problem based learning

This research paper demonstrates untraditional learning and teaching method that is developed from combination of experimentation, usage of computer simulations and problem based learning. Taking all previously mentioned methods together there can be created very successful learning environment which provides students to master electromagnetism more effectively. Research focuses on proper use of data acquisition modules and computer simulations in PBL teaching method. Based on the results of the research experimental PBL in various cases provides better learning outcomes, but there are also a few occasions where the results aren’t so pleasing. Overall PBL provides results that are at least as promising as results of other teaching and learning methods. Therefore this method will be utilized in Liepaja University to teach physics, especially electromagnetism

On one Mathematical Model for Dynamics of Propagation and Retention of Heat over New Fibre Insulation Coating

In circumstances, when it is important to replace insulation materials with high content of emissions during production it is necessary to create new heat and sound insulation material, which eliminates CO2 emissions, develop its production techniques and technological machinery – raw material chopper, pulp mixer, termopress, dryer chamber, formatting knifes, determine technical control parameters and control equipment, develop mathematical model of the material and calculation methods for design works. It is necessary to design, manufacture and experimentally test the respective technological equipment for insulation production pilot plant. To get exact physical parameters it is necessary design, manufacture and test unique laboratory equipment for determining the properties of insulation material. The mathematical model describing the dynamics of propagation and retention of heat over fibre insulation coating by taking "inner" specificities (graininess and porosity of layered structure of the considered fibre insulation) of heat insulator into account is proposed in the present paper

The Relation between Photoconductivity Threshold and Open-Circuit Voltage in Organic Solar Cells

Financial support provided by Scientific Research Project for Students and Young Researchers No. SJZ/2020/08 implemented at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART².Most of the solar cell parameters (short-circuit current, fill factor, power conversion efficiency) can only be determined by creating and measuring the solar cell. However, there is an empirical relation that links energy level values of the materials in the active layer to an open-circuit voltage (Uoc) of the solar cell. Due to a variety of possible methods used to determine energy level values and the dispersion of obtained results, this estimate is not always correct. Even if correct energy level values are obtained for separate materials, energy level shift takes place at the interfaces when two materials are mixed. That is why a simple and reliable experimental method for Uoc estimation is required. Usually, photoconductivity is used to obtain the energy gap between molecule ionization energy and electron affinity of a single material. When two materials are mixed, direct charge transfer from donor to acceptor molecule can be observed. The threshold energy (ECT) shows the real difference between donor molecule ionization energy and acceptor molecule electron affinity. This difference should correspond to the Uoc. The present study makes the comparison between the open-circuit voltage estimated from material energy level values, the obtained ECT values for various donor:acceptor systems, and the real Uoc obtained from solar cell measurements. Strong correlation between ECT and Uoc is obtained and the photoconductivity measurements can be used in the estimation of Uoc. © 2022 R. Grzibovskis et al., published by Sciendo.--//-- This is an open access article R. Grzibovskis, A. Ruduss, A. Polaks The Relation Between Photoconductivity Threshold and Open-Circuit Voltage in Organic Solar Cells, Latvian Journal of Physics and Technical Sciences 59 (1), 2022; doi:10.2478/lpts-2022-0003; published under the CC BY 4.0 licence.Scientific Research Project for Students and Young Researchers No. SJZ/2020/08; Institute of Solid State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²