Entangling photons using a charged quantum dot in a microcavity

We present two novel schemes to generate photon polarization entanglement via single electron spins confined in charged quantum dots inside microcavities. One scheme is via entangled remote electron spins followed by negatively-charged exciton emissions, and another scheme is via a single electron spin followed by the spin state measurement. Both schemes are based on giant circular birefringence and giant Faraday rotation induced by a single electron spin in a microcavity. Our schemes are deterministic and can generate an arbitrary amount of multi-photon entanglement. Following similar procedures, a scheme for a photon-spin quantum interface is proposed.Comment: 4 pages, 4 figure

Scalability of Shor's algorithm with a limited set of rotation gates

Typical circuit implementations of Shor's algorithm involve controlled rotation gates of magnitude $\pi/2^{2L}$ where $L$ is the binary length of the integer N to be factored. Such gates cannot be implemented exactly using existing fault-tolerant techniques. Approximating a given controlled $\pi/2^{d}$ rotation gate to within $\delta=O(1/2^{d})$ currently requires both a number of qubits and number of fault-tolerant gates that grows polynomially with $d$. In this paper we show that this additional growth in space and time complexity would severely limit the applicability of Shor's algorithm to large integers. Consequently, we study in detail the effect of using only controlled rotation gates with $d$ less than or equal to some $d_{\rm max}$. It is found that integers up to length $L_{\rm max} = O(4^{d_{\rm max}})$ can be factored without significant performance penalty implying that the cumbersome techniques of fault-tolerant computation only need to be used to create controlled rotation gates of magnitude $\pi/64$ if integers thousands of bits long are desired factored. Explicit fault-tolerant constructions of such gates are also discussed.Comment: Substantially revised version, twice as long as original. Two tables converted into one 8-part figure, new section added on the construction of arbitrary single-qubit rotations using only the fault-tolerant gate set. Substantial additional discussion and explanatory figures added throughout. (8 pages, 6 figures

A true concurrent model of smart contracts executions

The development of blockchain technologies has enabled the trustless execution of so-called smart contracts, i.e. programs that regulate the exchange of assets (e.g., cryptocurrency) between users. In a decentralized blockchain, the state of smart contracts is collaboratively maintained by a peer-to-peer network of mutually untrusted nodes, which collect from users a set of transactions (representing the required actions on contracts), and execute them in some order. Once this sequence of transactions is appended to the blockchain, the other nodes validate it, re-executing the transactions in the same order. The serial execution of transactions does not take advantage of the multi-core architecture of modern processors, so contributing to limit the throughput. In this paper we propose a true concurrent model of smart contract execution. Based on this, we show how static analysis of smart contracts can be exploited to parallelize the execution of transactions.Comment: Full version of the paper presented at COORDINATION 202

A revision of the tribe Coelidiini of the Oriental, Palearctic and Australian biogeographical regions (Hemiptera: Cicadellidae: Coelidiinae)

Within the tribe Coelidiini, subfamily Coelidiinae (Cicadellidae: Hemiptera), fragmentation of the genera Calodia Nielson, Olidiana McKamey and Taharana Nielson established the following 13 new genera: Cladolidia, type-species, Lodiana cladopenis Zhang; Creberulidia, type-species, Calodia paucita Nielson; Glaberana, type-species, Glaberana spadix, sp. nov.; Hamusolidia, type-species, Hamusolidia introrsa, sp. nov.; Hiatusorus, typespecies, Taharana schonhorsti Nielson; Laosolidia, type-species, Laosolidia complexa, sp. nov.; Orbisolidia, typespecies, Calodia spinocava Nielson; Singillatus, type-species, Lodiana furcata Nielson; Trinoridia, type-species, Trinoridia calcaris, sp. nov.; Tripesidia, type-species, Calodia warei Nielson; Tumidorus, type-species, Lodiana nielsoni Zhang; Webbolidia, type-species, Taharana webbi Nielson and Zhangolidia, type-species, Lodiana polyspinata Zhang. Nineteen genera in the tribe are treated. The following 62 new species in 12 genera are described, illustrated and photographed: Calodia bicompressa (India); C. birama (Philippines); C. propennata (India); C. sichuanensis (China); C. sinuata (Laos); C. vincula (China, Vietnam); Creberulidia corniger (Laos); C. inflata (Thailand); C. multipenicula (Cambodia); C. ordospinosa (Thailand); C. penicula (Thailand); Glaberana ampla (Thailand); G. dentilamina (Thailand); G. longilamina (Thailand); G. penita (Laos); G. spadix (Laos); G. stylafurcata (Indonesia); Hamusolidia introrsa (Laos); Hiatusorus aviformus (Laos); H. robustus (China); H. supraspinosus (Thailand); Laosolidia complexa (Laos); L. tuberis (Laos); L. longiserrata (Laos); Olidiana tuberis (Vietnam); O. bispiculata (Laos); O. filiata (Thailand); O. implicata (Thailand); O. inaequabilia (Thailand); O. lata (Laos); O. parafringa (Laos); O. pennata (Laos); O. tonkinensis (Vietnam); O. vincula (Vietnam); Singillatus gracilius (Indonesia); S. ventrospinatus (India); Taharana abstrusa (Thailand); T. angusta (Vietnam); T. biavicula (Thailand); T. biunca (Thailand); T. brevicutata (Thailand); T. caverna (Malaysia); T. exiquitas (Thailand); T. forcipia (Thailand); T. gracilata (Thailand); T. incisura (Thailand); T. intimacalcara (Thailand); T. lacertosa (Thailand); T. mediolata (Thailand); T. minutura (Thailand); T. oblongiserrata (Laos); T. subspinata (Thailand); T. sublamina (Thailand); T. phetchahabunesis (Thailand); T. protriangulata (Thailand); T. subtumida (Thailand); T. truncata (Thailand); Trinoridia calcaris (India); T. trifida (Malaysia); Tripesidia kubani (Laos); Webbolidia kristenseni (Thailand); W. magna (Laos). Taxonomy of all the genera is elucidated with a revised key to genera and species. The following formerly suppressed species are herein reinstated: Olidiana (Lodiana) flavofasciana Li, 1989, Olidiana (Lodiana) nigritibiana Li, 1987, Olidiana rufofasciana Li and Wang, 1989 and Webbolidia (Taharana) uniaristata Zhang, 1990. The following 3 species are new junior synonyms: Calodia flavinota Cai and Kuoh, 1993: 220 [= Calodia patricia (Jacobi), 1944: 49], Olidiana yangi McKamey 2006: 502 [= Lodiana (Olidiana) hamularis Xu, 2000: 220] and Taharana yinggenensis Zhang and Zhang, 1994: 96 [= Taharana (Coelidia) sparsa (Stål) 1854: 254]. Taharana hainana Zhang 1994: 132 is a nomen nudum based on the same name in Zhang’s thesis (1988) which name was cited later by Li and Wang 1991: 275. Lodiana hainana Cai and He 2002: 139 is also a nomen nudum. A replacement name proposed herein is caii, nom. nov. in the genus Olidiana; Zhang’s 1994: 71 illustrations of subgenital plate (I) and aedeagus (M) of “fasciana Li” does not appear to represent the respective illustrations in Li 1991: 357 and may represent a new species in the genus Glaberana. The name of Olidiana nigridorsum (Cai and Shen) is changed to Olidiana nigridorsa (Cai and Shen) to agree with gender. Among 12 genera, 102 species are proposed in new combinations. Lodiana reductusi Xu and Kuoh, 1997 and Lodiana spicata Xu and Kuoh, 1997 are declared incertae sedis after attempts failed to locate the original descriptions and type specimens. Both species are provisionally assigned to the genus Olidiana. Two syntype specimens of Jassus egregius Schumacher, previously thought to be lost, were located in the Senckenberg Deutsches Entomologisches Institut, Müncheberg, Germany. The male specimen is designated lectotype herein. Six species in the Olidiana brevis (Walker) interspecific variation complex are elucidated with illustrations of male genitalia features. New records, an updated checklist and a synoptic catalogue are also provided. All taxa including 264 valid species and 304 names are indexed

Finite-Time Disentanglement via Spontaneous Emission

We show that under the influence of pure vacuum noise two entangled qubits become completely disentangled in a finite time, and in a specific example we find the time to be given by $\ln \Big(\frac{2 +\sqrt 2}{2}\Big)$ times the usual spontaneous lifetime.Comment: revtex, 4 pages, 2 figure

The Trilinear Hamiltonian: A Zero Dimensional Model of Hawking Radiation from a Quantized Source

We investigate a quantum parametric amplifier with dynamical pump mode, viewed as a zero-dimensional model of Hawking radiation from an evaporating black hole. The conditions are derived under which the spectrum of particles generated from vacuum fluctuations deviates from the thermal spectrum predicted for the conventional parametric amplifier. We find that significant deviations arise when the pump mode (black hole) has emitted nearly half of its initial energy into the signal (Hawking radiation) and idler (in-falling particle) modes. As a model of black hole dynamics, this finding lends support to the view that late-time Hawking radiation contains information about the quantum state of the black hole and is entangled with the black hole's quantum gravitational degrees of freedom.Comment: 18 pages, 6 figures, Submitted to New Journal of Physics focus issue: "Classical and Quantum Analogues for Gravitational Phenomena and Related Effects

Generalized Limits for Parameter Sensitivity via Quantum Ziv-Zakai Bound

We study the generalized limit for parameter sensitivity in quantum estimation theory considering the effects of repeated and adaptive measurements. Based on the quantum Ziv-Zakai bound, we derive some lower bounds for parameter sensitivity when the Hamiltonian of system is unbounded and when the adaptive measurements are implemented on the system. We also prove that the parameter sensitivity is bounded by the limit of the minimum detectable parameter. In particular, we examine several known states in quantum phase estimation with non-interacting photons, and show that they can not perform better than Heisenberg limit in a much simpler way with our result.Comment: 8pages, 5 figure

Nanomolar-potency 'co-potentiator' therapy for cystic fibrosis caused by a defined subset of minimal function CFTR mutants.

Available CFTR modulators provide no therapeutic benefit for cystic fibrosis (CF) caused by many loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, including N1303K. We previously introduced the concept of 'co-potentiators' (combination-potentiators) to rescue CFTR function in some minimal function CFTR mutants. Herein, a screen of ~120,000 drug-like synthetic small molecules identified active co-potentiators of pyrazoloquinoline, piperidine-pyridoindole, tetrahydroquinoline and phenylazepine classes, with EC50 down to ~300 nM following initial structure-activity studies. Increased CFTR chloride conductance by up to 8-fold was observed when a co-potentiator (termed 'Class II potentiator') was used with a classical potentiator ('Class I potentiator') such as VX-770 or GLPG1837. To investigate the range of CFTR mutations benefitted by co-potentiators, 14 CF-associated CFTR mutations were studied in transfected cell models. Co-potentiator efficacy was found for CFTR missense, deletion and nonsense mutations in nucleotide binding domain-2 (NBD2), including W1282X, N1303K, c.3700A > G and Q1313X (with corrector for some mutations). In contrast, CFTR mutations G85E, R334W, R347P, V520F, R560T, A561E, M1101K and R1162X showed no co-potentiator activity, even with corrector. Co-potentiator efficacy was confirmed in primary human bronchial epithelial cell cultures generated from a N1303K homozygous CF subject. The Class II potentiators identified here may have clinical benefit for CF caused by mutations in the NBD2 domain of CFTR

Unfrustrated Qudit Chains and their Ground States

We investigate chains of 'd' dimensional quantum spins (qudits) on a line with generic nearest neighbor interactions without translational invariance. We find the conditions under which these systems are not frustrated, i.e. when the ground states are also the common ground states of all the local terms in the Hamiltonians. The states of a quantum spin chain are naturally represented in the Matrix Product States (MPS) framework. Using imaginary time evolution in the MPS ansatz, we numerically investigate the range of parameters in which we expect the ground states to be highly entangled and find them hard to approximate using our MPS method.Comment: 5 pages, 5 figures. Typos correcte

Single-qubit gates and measurements in the surface acoustic wave quantum computer

In the surface acoustic wave quantum computer, the spin state of an electron trapped in a moving quantum dot comprises the physical qubit of the scheme. Via detailed analytic and numerical modeling of the qubit dynamics, we discuss the effect of excitations into higher-energy orbital states of the quantum dot that occur when the qubits pass through magnetic fields. We describe how single-qubit quantum operations, such as single-qubit rotations and single-qubit measurements, can be performed using only localized static magnetic fields. The models provide useful parameter regimes to be explored experimentally when the requirements on semiconductor gate fabrication and the nanomagnetics technology are met in the future.Comment: 13 pages, 10 figures, submitted to Phys. Rev.