Comment on "Information flow of quantum states interacting with closed timelike curves"

We show that recent results on the interaction of causality-respecting particles with particles on closed timelike curves derived in [Phys. Rev. A 82, 062330 (2010)] depend on ambiguous assumption about the form of the state which is inputted into the proposed equivalent circuit. Choosing different form of this state leads to opposite conclusion on the power of closed timelike curves

Gaussian state entanglement witnessing through lossy compression

We propose a method to witness entanglement between two continuous-variable systems in a Gaussian state. Its key ingredient is a local lossy state transfer from the original spatially separated systems onto two spatially separated qubits. The qubits are initially in a pure product state, therefore by detecting entanglement between the qubits we witness entanglement between the two original systems. This method greatly simplifies entanglement witnessing in complex systems.Comment: 5 pages, 2 figure

Higher dimensional entanglement without correlations

It has been demonstrated both theoretically and experimentally that genuine multipartite entanglement between qubits can exist even in the absence of multipartite correlations. Here we provide first examples of this effect in higher dimensional systems -- qudits. We construct states in which genuine $N$-partite entanglement between qudits is supported only by correlations involving strictly less than $N$ particles. The construction differs in several aspects from the ones for qubits. The states introduced here are a natural test-bed for candidate quantifiers of genuinely multipartite quantum correlations.Comment: 6 pages, 1 figur

High validity entanglement verification with finite copies of a quantum state

Detecting entanglement of multipartite quantum states is an inherently probabilistic process due to a finite number of measured samples. The level of confidence of entanglement detection can be used to quantify the probability that the measured signal is coming from a separable state and provides a meaningful figure of merit for big data sets. Yet, for limited sample sizes, to avoid serious misinterpretations of the experimental results, one should not only consider the probability that a separable state gave rise to the measured signal, but should also include information about the probability that the signal came from an entangled state. We demonstrate this explicitly and propose a comprehensive method of entanglement detection when only a very limited amount of data is available. The method is based on a non-linear combination of correlation functions and is independent of system size. As an example, we derive the optimal number of measurement settings and clicks per setting revealing entanglement with only 20 copies of a state.Comment: 13 pages, 4 figure

The effect of triazine- and urea-type herbicides on photosynthetic apparatus in cucumber leaves

About a half of the herbicides used at present in agnculture inhibit the light reactions in photosynthesis. Triazines and phenylureas shut down the photosynthetic process in susceptible plants by binding to specific sites within the plants photosystem II (PS II) complex. Both of them bind at the QB site on the Dl protein of PS II, and prevent the transport of electrons between the primary electron acceptor Q and the plastoquinone (PQ). Herbicides can be highly toxic to human and animal health (triazines are possible human carcinogens). Their indiscriminate use has serious environmental implications, for example pollution of soil and water. We compare two heibicides to investigate the one of lowest environmental toxicity but of high toxicity to weeds

Photosynthetic activity of C₃ and C₄ plants under salt stress

W pracy wykazano, że działanie NaCl powoduje u pszenicy i kukurydzy obniżenie takich parametrów indukcji fluorescenci chlorofilu jak: maksymalna (potencjalna) wydajność kwantowa PS II (Fv/Fm), aktualna (fotochemiczna) wydajność kwantowa PS II (ΦPSII), wskaźnik witalności (Rfd) i współczynnik fotochemicznego wygaszania fluorescencji (qP), przy jednoczesnym wzroście wartości współczynnika niefotochemicznego wygaszania fluorescencji (qN). Obniżenie Fv/Fm, ΦPSII, Rfd, qP i podwyższenie qN były dużo wyraźniejsze u pszenicy należącej do roślin typu C₃, niż u kukurydzy należącej do typu C₄. Zaobserwowano, że w rezultacie zasolenia w liściach badanych roślin nastąpiła redukcja przewodności aparatów szparkowych i w konsekwencji ograniczenie transpiracji. Efekt ten był znacznie szybszy i głębszy w przypadku kukurydzy. Obecność jonów soli w podłożu spowodowała znaczne zahamowanie intensywności asymilacji CO₂ w liściach - dużo większe u pszenicy, niż u kukurydzy. Wyniki sugerują, że PS II kukurydzy (C₄) jest mniej wrażliwy na działanie stresu solnego, a sprawność fotosyntetycznego transportu elektronów w tych warunkach jest większa, niż u pszenicy (C₃). Wartości Rfd wykazały, że konwersja zaabsorbowanej energii i wykorzystanie produktów fazy świetlnej w reakcjach niezależnych bezpośrednio od światła są bardziej efektywne w przypadku kukurydzy. Pomiary przewodności szparkowej i transpiracji ujawniły, że kukurydza lepiej zapobiega utracie wody niż pszenica. Mimo silnego przymknięcia aparatów szparkowych wydajność asymilacji utrzymywała się u kukurydzy na wysokim poziomie.In wheat and maize leaves, NaCl in the nutrient solution decreased the potential quantum efficiency of PS II (Fv/Fm), actual quantum yield of PS II (ΦPSII), vitality index (Rfd) and photochemical quenching coefficient (qP) but increased the non-photochemical quenching coefficient (qN). The reduction of Fv/Fm, ΦPSII, Rfd, qP as well as the increase of qN was more marked in wheat than in maize treated with NaCl. High salinity in the rhizosphere lowered the leaf stomatal conductance (Gs) and, consequently, the transpiration rate (E). Those parameters were stronger reduced in maize than in wheat leaves. Also the rate of CO₂ assimilation was distinctly diminished by NaCl and its effect was much more pronounced in wheat. The above results suggest that in maize (C₄) the PS II is less sensitive to salt injuries and that the photosynthetic electron transport chain is more efficient than in wheat (C₃). The values of vitality index showed that energy conversion and its utilization in the carbon metabolism is much more efficient in maize. In addition, the changes in leaf stomata conductance and transpiration rate indicate that C₄ are relatively better adapted to prevent the loss of water than C₃. In spite of strong stomata closing, CO₂ assimilation rate in maize is less decreased than in wheat