144 research outputs found
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 value no larger than
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
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
Adaptive surface code for quantum error correction in the presence of temporary or permanent defects
Whether it is at the fabrication stage or during the course of the quantum
computation, e.g. because of high-energy events like cosmic rays, the qubits
constituting an error correcting code may be rendered inoperable. Such defects
may correspond to individual qubits or to clusters and could potentially
disrupt the code sufficiently to generate logical errors. In this paper, we
explore a novel adaptive approach for surface code quantum error correction on
a defective lattice. We show that combining an appropriate defect detection
algorithm and a quarantine of the identified zone allows one to preserve the
advantage of quantum error correction at finite code sizes, at the cost of a
qubit overhead that scales with the size of the defect. Our numerics indicate
that the code's threshold need not be significantly affected; for example, for
a certain scenario where small defects repeatedly arise in each logical qubit,
the noise threshold is (versus the defect-free case of ). These
results pave the way to the experimental implementation of large-scale quantum
computers where defects will be inevitable.Comment: 12 pages, 9 figure
First report of infestation of cassava fruit, Manihot esculenta, by Neosilba perezi (Romero & Ruppell) (Lonchaeidae) in Brazil.
Primer registro de Anastrepha pseudoparallela Loew (Diptera: Tephritidae) infestando pasifloras en Perú
Several species of the genus Anastrepha Schiner are associated to different hosts and have a great economic importance in fruit crops of the Neotropical region. Ripe and unripe fruits of six passion flowers species were sampled in Oxapampa during 2016 and 2018. Larvae of Anastrepha pseudoparallela Loew (Diptera: Tephritidae) were detected infesting fruits of Passiflora ambigua Hemsl and Passiflora quadrangularis L. For the first time, this fruit fly species is recorded attacking fruits of passion flowers in Peru.Diversas especies del género Anastrepha Schiner están asociadas a diferentes hospederos y tienen gran importancia económica en la fruticultura de la región Neotropical. Frutos maduros e inmaduros de seis especies de Passiflora L. fueron colectados en Oxapampa durante el 2016 y 2018. Larvas de Anastrepha pseudoparallela Loew (Diptera: Tephritidae) fueron encontradas infestando frutos de Passiflora ambigua Hemsl y Passiflora quadrangularis L. Por primera vez, esta especie de mosca es registrada atacando frutos de pasifloras en el Perú
First report of Lonchaeidae (Diptera) infesting fruits of Byrsonima crassifolia in Brazil.
Murici, Byrsonima crassifolia (L.) Kunth (Malpighiaceae), is native to the Amazon region and several other regions of tropical America. The fruits are small globose drupes with fleshy yellow mesocarp (pulp) and characteristic flavor and aroma. They are consumed fresh as juice, jam, liquor and sweets (León 1968; Donadio et al. 2002; Lorenzi et al. 2006). In addition, fruits of this species have been widely used in the traditional medicine by its antimicrobial and antidepressant properties (Martínez-Vázquez et al. 1999; Herrera-Ruiz et al. 2011). The only record of fruit flies (Diptera) associated to fruits of B. crassifolia in Brazil was published by Pereira et al. (2008) from material collected in the state of Amapá during 2005 and 2006. In their work, a total number of 7,915 fruits (16.02 kg) was collected in 24 sampling points distributed in the municipalities of Macapá, Mazagão and Porto Grande. Three samples were infested by fruit flies of the family Tephritidae (one in Macapá, 0.01 puparia/fruit; two in Mazagão, 0.10 and 0.15 puparia/fruit). Anastrepha striata Schiner, 1868 (10 specimens), A. obliqua (Macquart, 1835) (8 specimens) and A. fraterculus (Wiedemann, 1830) (3 specimens) were recovered in those collections. In other samples of B. crassifolia collected in the Brazilian Amazon (states of Amapá and Rondônia), no fruit flies specimens were obtained (Deus et al. 2009; Pereira et al. 2010; Silva et al. 2011a). In Mexico, the presence of A. serpentina (Wiedemann, 1830) in B. crassifolia was recorded in the state of Chiapas (Aluja et al. 1987). However, the presence of Lonchaeidae (Diptera) species in B. crassifolia was not recorded in either study
First report of natural infestation of Pereskia aculeata Mill. (Cactaceae) by Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Brazil.
This is the first report of the natural infestation of fruits of Pereska aculeata Mill. (Cactaceae) by the Mediterranean fruit f1y Ceratilis capitala (Wiedemann) (Diptera: Tephritidae) in Brazil. We also obtained specimens of Anaslrepha barbiellinii Lima (Tephritidae) and Neosilba sp. (Lonchaeidae), and of the parasitoid Doryctobracon areolatus (Szépligeti) (Hymenoptera: Braconidae)
Diversidade e variação sazonal de moscas-das-frutas (Diptera: Tephritidae, Lonchaeidae) e seus parasitóides (Hymenoptera: Braconidae, Figitidae) em pomares de goiaba, nêspera e pêssego
This work was carried out in orchards of guava progenies, and loquat and peach cultivars, in Monte Alegre do Sul, SP, Brazil, in 2002 and 2003. Guavas and loquats were bagged and unbagged bi-weekly and weekly, respectively, for assessment of the infestation period. Peach was only bagged weekly. The assays started when the fruits were at the beginning of development, but still green. Ripe fruits were taken to the laboratory and placed individually into plastic cups. McPhail plastic traps containing torula yeast were hung from January 2002 to January 2004 to assess the fruit fly population in each orchard, but only the Ceratitis capitata population is here discussed. Five tephritid species were reared from the fruits: Anastrepha bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart), A. sororcula Zucchi, and C. capitata, in addition to six lonchaeid species: Neosilba certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. zadolicha McAlpine and Steyskal, Neosilba sp. 4, and Neosilba sp. 10 (both species are in the process of being described by P. C. Strikis), as well as some unidentified Neosilba species. Ten parasitoid species were obtained from fruit fly puparia, of which five were braconids: Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan, and Utetes anastrephae (Viereck), and five figitids: Aganaspis pelleranoi (Brèthes), Dicerataspis grenadensis Ashmead, Lopheucoila anastrephae (Rhower), Leptopilina boulardi (Barbotin, Carlton and Kelner-Pillaut), and Trybliographa infuscata Diaz, Gallardo and Uchôa. Ceratitis capitata showed a seasonal behavior with population density peaking at the second semester of each year. Anastrepha and Neosilba species remained in the orchards throughout both years.Este trabalho foi realizado em três pomares em Monte Alegre do Sul, SP, em 2002 e 2003, representados por coleção de progênies de goiabeiras, de cultivares de nespereiras e de cultivares de pessegueiros. O período de infestação foi determinado por meio de ensacamento e desensacamento quinzenal e semanal de goiabas e nêsperas, respectivamente, e pelo ensacamento semanal de pêssegos. Os ensaios iniciaram-se com os frutos verdes (princípio de desenvolvimento). Os frutos maduros foram levados ao laboratório e acondicionados individualmente em copos plásticos. A flutuação populacional de Ceratitis capitata (Wiedemann) foi avaliada por meio de armadilhas plásticas modelo McPhail com torula em cada pomar, de janeiro/2002 a janeiro/2004. Dos frutos foram obtidas cinco espécies de tefritídeos: Anastrepha bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart), A. sororcula Zucchi e C. capitata e seis de lonqueídeos: Neosilba certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. zadolicha McAlpine and Steyskal, Neosilba sp. 4 e Neosilba sp. 10, além de algumas espécies não-identificadas. Foram obtidas 10 espécies de parasitóides, cinco da família Braconidae - Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan e Utetes anastrephae (Viereck) - e cinco da família Figitidae - Aganaspis pelleranoi (Brèthes), Dicerataspis grenadensis Ashmead, Lopheucoila anastrephae (Rhower), Leptopilina boulardi (Barbotin, Carlton and Kelner-Pillaut) e Trybliographa infuscata Diaz, Gallardo and Uchôa. Ceratitis capitata apresentou comportamento sazonal com picos populacionais durante o segundo semestre dos dois anos. As espécies de Anastrepha e de Neosilba permaneceram nos pomares durante os dois anos
Diversidade e variação sazonal de moscas-das-frutas (Diptera: Tephritidae, Lonchaeidae) e seus parasitóides (Hymenoptera: Braconidae, Figitidae) em pomares de goiaba, nêspera e pêssego
This work was carried out in orchards of guava progenies, and loquat and peach cultivars, in Monte Alegre do Sul, SP, Brazil, in 2002 and 2003. Guavas and loquats were bagged and unbagged bi-weekly and weekly, respectively, for assessment of the infestation period. Peach was only bagged weekly. The assays started when the fruits were at the beginning of development, but still green. Ripe fruits were taken to the laboratory and placed individually into plastic cups. McPhail plastic traps containing torula yeast were hung from January 2002 to January 2004 to assess the fruit fly population in each orchard, but only the Ceratitis capitata population is here discussed. Five tephritid species were reared from the fruits: Anastrepha bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart), A. sororcula Zucchi, and C. capitata, in addition to six lonchaeid species: Neosilba certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. zadolicha McAlpine and Steyskal, Neosilba sp. 4, and Neosilba sp. 10 (both species are in the process of being described by P. C. Strikis), as well as some unidentified Neosilba species. Ten parasitoid species were obtained from fruit fly puparia, of which five were braconids: Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan, and Utetes anastrephae (Viereck), and five figitids: Aganaspis pelleranoi (Brèthes), Dicerataspis grenadensis Ashmead, Lopheucoila anastrephae (Rhower), Leptopilina boulardi (Barbotin, Carlton and Kelner-Pillaut), and Trybliographa infuscata Diaz, Gallardo and Uchôa. Ceratitis capitata showed a seasonal behavior with population density peaking at the second semester of each year. Anastrepha and Neosilba species remained in the orchards throughout both years6913140sem informaçãoEste trabalho foi realizado em três pomares em Monte Alegre do Sul, SP, em 2002 e 2003, representados por coleção de progênies de goiabeiras, de cultivares de nespereiras e de cultivares de pessegueiros. O período de infestação foi determinado por meio de ensacamento e desensacamento quinzenal e semanal de goiabas e nêsperas, respectivamente, e pelo ensacamento semanal de pêssegos. Os ensaios iniciaram-se com os frutos verdes (princípio de desenvolvimento). Os frutos maduros foram levados ao laboratório e acondicionados individualmente em copos plásticos. A flutuação populacional de Ceratitis capitata (Wiedemann) foi avaliada por meio de armadilhas plásticas modelo McPhail com torula em cada pomar, de janeiro/2002 a janeiro/2004. Dos frutos foram obtidas cinco espécies de tefritídeos: Anastrepha bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart), A. sororcula Zucchi e C. capitata e seis de lonqueídeos: Neosilba certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. zadolicha McAlpine and Steyskal, Neosilba sp. 4 e Neosilba sp. 10, além de algumas espécies não-identificadas. Foram obtidas 10 espécies de parasitóides, cinco da família Braconidae - Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan e Utetes anastrephae (Viereck) - e cinco da família Figitidae - Aganaspis pelleranoi (Brèthes), Dicerataspis grenadensis Ashmead, Lopheucoila anastrephae (Rhower), Leptopilina boulardi (Barbotin, Carlton and Kelner-Pillaut) e Trybliographa infuscata Diaz, Gallardo and Uchôa. Ceratitis capitata apresentou comportamento sazonal com picos populacionais durante o segundo semestre dos dois anos. As espécies de Anastrepha e de Neosilba permaneceram nos pomares durante os dois anossem informaçã
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