133,638 research outputs found
Violation of a Leggett-Garg inequality with ideal non-invasive measurements
Get PDFThe quantum superposition principle states that an entity can exist in two different states simultaneously, counter to our 'classical' intuition. Is it possible to understand a given system's behaviour without such a concept? A test designed by Leggett and Garg can rule out this possibility. The test, originally intended for macroscopic objects, has been implemented in various systems. However to date no experiment has employed the 'ideal negative result' measurements that are required for the most robust test. Here we introduce a general protocol for these special measurements using an ancillary system, which acts as a local measuring device but which need not be perfectly prepared. We report an experimental realization using spin-bearing phosphorus impurities in silicon. The results demonstrate the necessity of a non-classical picture for this class of microscopic system. Our procedure can be applied to systems of any size, whether individually controlled or in a spatial ensemble.</p
Comment on 'A scattering quantum circuit for measuring Bell's time inequality:a nuclear magnetic resonance demonstration using maximally mixed states'
Get PDFA recent paper by Souza, Oliveira and Sarthour (SOS) reports the experimental violation of a Leggett-Garg (LG) inequality (sometimes referred to as a temporal Bell inequality). The inequality tests for quantum mechanical superposition: if the inequality is violated, the dynamics cannot be explained by a large class of classical theories under the heading of macrorealism. Experimental tests of the LG inequality are beset by the difficulty of carrying out the necessary so-called 'non-invasive' measurements (which for the macrorealist will extract information from a system of interest without disturbing it). SOS argue that they nevertheless achieve this difficult goal by putting the system in a maximally mixed state. The system then allegedly undergoes no perturbation during their experiment. Unfortunately, the method is ultimately unconvincing to a skeptical macrorealist and so the conclusions drawn by SOS are unjustified.</p
Temporal quantum correlations and Leggett-Garg inequalities in multilevel systems
No full textWe show that the quantum bound for temporal correlations in a Leggett-Garg test, analogous to the Tsirelson bound for spatial correlations in a Bell test, strongly depends on the number of levels N that can be accessed by the measurement apparatus via projective measurements. We provide exact bounds for small N that exceed the known bound for the Leggett-Garg inequality, and we show that in the limit N → ∞ the Leggett-Garg inequality can be violated up to its algebraic maximum
Sampling hurdles : “Borderline Illegitimate” to legitimate data.
Get PDFIn this paper the author discusses how sampling access and recruitment problems encountered in an in-depth interview study heightened her sensitivity to “borderline illegitimate” data. The term illegitimate data usually refers to the data collected during a covert study, whereas “legitimate” data are collected during an overt study. Hence, data collected during any nonconsented period(s) of an overt study lie on the borderline of illegitimacy and legitimacy, and constitute what the author calls borderline illegitimate data. Such data need legitimization before use. The borderline illegitimate data were collected during the pre- and postinterview stages of her study as they explained how medical and ethnic cultures and sensitivity to racism as a topic combined to create sample recruitment difficulties of the study. The author later legitimized them by sharing them with the participants, guaranteeing anonymity, and asking their permission to use them
Avoiding Loopholes with Hybrid Bell-Leggett-Garg Inequalities
Get PDFBy combining the postulates of macrorealism with Bell locality, we derive a qualitatively different hybrid inequality that avoids two loopholes that commonly appear in Leggett-Garg and Bell inequalities. First, locally invasive measurements can be used, which avoids the “clumsiness” Leggett-Garg inequality loophole. Second, a single experimental ensemble with fixed analyzer settings is sampled, which avoids the “disjoint sampling” Bell inequality loophole. The derived hybrid inequality has the same form as the Clauser-Horne-Shimony-Holt Bell inequality; however, its quantum violation intriguingly requires weak measurements. A realistic explanation of an observed violation requires either the failure of Bell locality or a preparation conspiracy of finely tuned and nonlocally correlated noise. Modern superconducting and optical systems are poised to implement this test
Memory-Sample Lower Bounds for Learning Parity with Noise
Get PDFIn this work, we show, for the well-studied problem of learning parity under noise, where a learner tries to learn x = (x₁,…,x_n) ∈ {0,1}ⁿ from a stream of random linear equations over ₂ that are correct with probability 1/2+ε and flipped with probability 1/2-ε (0 < ε < 1/2), that any learning algorithm requires either a memory of size Ω(n²/ε) or an exponential number of samples.
In fact, we study memory-sample lower bounds for a large class of learning problems, as characterized by [Garg et al., 2018], when the samples are noisy. A matrix M: A × X → {-1,1} corresponds to the following learning problem with error parameter ε: an unknown element x ∈ X is chosen uniformly at random. A learner tries to learn x from a stream of samples, (a₁, b₁), (a₂, b₂) …, where for every i, a_i ∈ A is chosen uniformly at random and b_i = M(a_i,x) with probability 1/2+ε and b_i = -M(a_i,x) with probability 1/2-ε (0 < ε < 1/2). Assume that k,, r are such that any submatrix of M of at least 2^{-k} ⋅ |A| rows and at least 2^{-} ⋅ |X| columns, has a bias of at most 2^{-r}. We show that any learning algorithm for the learning problem corresponding to M, with error parameter ε, requires either a memory of size at least Ω((k⋅)/ε), or at least 2^{Ω(r)} samples. The result holds even if the learner has an exponentially small success probability (of 2^{-Ω(r)}). In particular, this shows that for a large class of learning problems, same as those in [Garg et al., 2018], any learning algorithm requires either a memory of size at least Ω(((log|X|)⋅(log|A|))/ε) or an exponential number of noisy samples.
Our proof is based on adapting the arguments in [Ran Raz, 2017; Garg et al., 2018] to the noisy case
Higher-dimensional Bruckner–Garg type theorem
No full textAbstractIn this paper, we investigate several properties of maps from a compactum X to an n-dimensional (combinatorial) manifold Mn. We introduce the notions of stable point and locally extreme point of map, and we prove a higher-dimensional Bruckner–Garg type theorem for the fiber structure of a generic map in the space C(X,Mn) of maps from a compactum X with dimX⩾n to an n-dimensional manifold Mn (n⩾1). As applications, we also study the spaces of Bing maps, Lelek maps, k-dimensional maps and Krasinkiewicz maps in C(X,Mn)
Gastrointestinal complications associated with catheter ablation for atrial fibrillation
No full textsj-pdf-1-lrt-10.1177_14771535211063624 – Supplemental Material for Analysis, evaluation and integration of modular natural illumination system using a rectangular Fresnel lens for high performance
No full textSupplemental Material, sj-pdf-1-lrt-10.1177_14771535211063624 for Analysis, evaluation and integration of modular natural illumination system using a rectangular Fresnel lens for high performance by H Garg, DS Bisht, K Sharma, V Kumar, K Kaur and N Garg in Lighting Research & Technology</p
Fejervarya neilcoxi Garg & Biju 2017, sp. nov.
No full textFejervarya neilcoxi sp. nov. http://zoobank.org/urn:lsid:zoobank.org:act:E3B863F6-7443-495C-A698-8543FF6C4197 Neil Cox’s Burrowing Frog (Tables 1–7; Figs. 1–6, 12) Etymology. This species is named for Dr Neil Cox, Manager of the IUCN-Conservation International Biodiversity Assessment Unit. Neil has been associated with the IUCN Red List in a variety of capacities including species assessment and management, and the new species is named particularly in appreciation of his contribution towards the Global Amphibian Assessment. The species epithet neilcoxi is treated as a noun in the genitive case. Holotype. ZSI/ WGRC /V/A/951, an adult male, from Parambikulam (10°24’36.5” N 76°46’04.6” E, 650 m asl), Palakkad district, Kerala state, India, collected by SDB and SG on 0 8 July 2015. Paratypes. ZSI/ WGRC /V/A/952–953, two adult males, and ZSI/ WGRC /V/A/954, an adult female collected along with the holotype; ZSI/ WGRC /V/A/955, an adult female, from the same locality as holotype, collected by SDB and team on 12 August 2012. Genetic relationship. Phylogenetically, Fejervarya neilcoxi sp. nov. is nested in the Fejervarya rufescens group (Figs. 1–2) of the Western Ghats. The average uncorrected pairwise genetic divergence with F. rufescens is 3.9% (range 3.7–4.1%, N = 14) for 16S, 11.2% (range 10.7–11.5%, N = 10) for COI, and 9.7% (range 8.7–10.8%, N = 10) for Cytb; 4.9% (range 4.9–5.0%, N = 8) for 16S, 11.0% (range 10.9–11.1%, N = 6) for COI, and 12.8% (range 12.7–12.9%, N = 6) for Cytb with F. cepfi sp. nov.; 4.7% (N = 2) for 16S, 11.1% (N = 2) for COI, and 10.8% (N = 2) for Cytb with F. kadar sp. nov.; and 3.5% (N = 8) for 16S, 8.9% (N = 6) for COI, and 10.4% (range 10.3–10.4%, N = 6) for Cytb with F. manoharani sp. nov. (Table 2). Diagnosis. Fejervarya neilcoxi sp. nov. can be distinguished from known congeners by the following combination of morphological characters: (1) medium male adult size (SVL 32.0– 33.3 mm, N = 3); (2) stout body; (3) dorsal skin prominently granular with spinular projections; (4) snout subovoid in dorsal view and obtuse in lateral view; (5) presence of rictal gland at labial commissure of the mouth; (6) eye length nearly equal to snout length (male EL/SL ratio 97.6–97.7%, N = 3); (7) tympanum diameter less than half of eye length, (male TYD /EL ratio 38.1–39.0%, N = 3); (8) inter upper eyelid width nearly three-fourth of upper eyelid width (male IUE / UEW ratio 72.0–75.0%, N = 3) and internarial distance (male IUE /IN ratio 70.0–75.0%, N = 3); (9) prominent shovelshaped inner metatarsal tubercle prominent and small outer metatarsal tubercle; (10) webbing between toes small. Morphological comparison. Based on the overall morphology and comparable body size, Fejervarya neilcoxi sp. nov. could be confused with the known species F. rufescens and three new species, F. cepfi sp. nov., F. kadar sp. nov. and F. manoharani sp. nov. However, Fejervarya neilcoxi differs from F. rufescens by its dorsal skin prominently granular with spinular projections (vs. shagreened to granular without prominent warts); snout obtuse in lateral view (vs. rounded); tympanum to eye distance relatively longer or nearly equal to tympanum diameter, male TYE 1.4–1.6 mm, TYD 1.6 mm, TYE/TYD ratio 87.5–100%, N = 3 (vs. shorter, TYE 1.1–1.3 mm, TYD 1.6–2.2 mm, TYE/TYD ratio 50.0–76.5%, N = 6); inter upper eyelid width relatively wider than upper eyelid width, male IUE 1.8–2.1 mm, UEW 2.5–2.9 mm, IUE/UEW ratio 72.0–75.0%, N = 3 (vs. relatively narrower, male IUE 1.4–1.8 mm, UEW 2.9–3.5 mm, IUE/UEW ratio 42.9–58.6%, N = 6); thigh shorter than shank length, male TL 14.0– 14.5 mm, SHL 15.3–15.8, TL/SHL ratio 91.5–92.2%, N = 3 (vs. equal or longer, male TL 14.7–15.8, SHL 14.5–15.8, TL/SHL ratio 100–102.1%, N = 6); thigh length shorter than foot length, male TL 14.0– 14.5 mm, FOL 16.3–16.9 mm, TL/ FOL ratio 85.4–87.1%, N = 3 (vs. nearly equal, male TL 14.7–15.8 mm, FOL 14.8–15.9 mm, TL/FOL ratio 98.0–99.4%, N = 6); and relatively less webbing between toes, male I2 – –2 II2 – –3– III2 1/2–3 1/2 IV3 1/2– 2V, specifically the third toe webbing below the first subarticular tubercle on the outside and fourth toe webbing below the second subarticular tubercle on either side (vs. more, male I2 – –2 II2 – – 3–III 2– 3IV 3– 2V). Fejervarya neilcoxi differs from F. cepfi by its dorsal skin with relatively more prominent glandular warts (vs. less); horizontal diameter of eye nearly equal to snout length, EL 4.1–4.2 mm, SL 4.2–4.3 mm, EL/SL ratio 97.6–97.7%, N = 3 (vs. smaller, male EL 3.4–3.5 mm, SL 4.6–4.8 mm, EL/SL ratio 72.9–73.9%, N = 2); tympanum diameter less than half of horizontal diameter of eye, male TYD 1.6 mm, EL 4.1–4.2 mm, TYD/EL ratio 38.1–39.0%, N = 3 (vs. nearly half, male TYD 1.8 mm, EL 3.4–3.5 mm, TYD/EL ratio 51.4–52.9%, N = 2); inter upper eyelid width narrower than upper eyelid width, male IUE 1.8–2.1 mm, UEW 2.5–2.9 mm, IUE/UEW ratio 72.0–75.0%, N = 3 (vs. nearly equal, male IUE 2.4–2.5 mm, UEW 2.5–2.6 mm, IUE/UEW ratio 96.0–96.2%, N = 2); inter upper eyelid width narrower than internarial distance, male IUE 1.8–2.1 mm, IN 2.5–3.0 mm, IUE/IN ratio 70.0–75.0%, N = 3 (vs. nearly equal, male IUE 2.4–2.5 mm, IN 2.5 mm, IUE/IN ratio 96–100%, N = 2); and relatively less webbing between toes, male I2 – –2 II2 – –3– III2 1/2–3 1/2 IV3 1/2– 2V (vs. more, male I1 +–2– II1 +– 3–III 2– 3IV 3–1 1/ 2V). Fejervarya neilcoxi differs from F. kadar by its dorsal skin with prominent granular projections (vs. with scattered glandular warts); snout subovoid in dorsal view (vs. rounded); eye length nearly equal to snout length, male EL 4.1–4.2 mm, SL 4.2–4.3 mm, EL/SL ratio 97.6–97.7%, N = 3 (vs. relatively shorter, male EL 4.0– 4.2 mm, SL 4.4–4.5 mm, EL/SL ratio 88.9–93.3%, N = 3); inter upper eyelid width relatively wider than upper eyelid width, male IUE 1.8–2.1 mm, UEW 2.5–2.9 mm, IUE/UEW ratio 72.0–75.0%, N = 3 (vs. narrower, male IUE 1.7–1.8 mm, UEW 3.0– 3.3 mm, IUE/UEW ratio 53.1–60.0%, N = 3); thigh length shorter than shank length, male TL 14.0– 14.5 mm, SHL 15.3–15.8 mm, TL/SHL ratio 91.5–92.2%, N = 3 (vs. nearly equal, male TL 14.5–15.4 mm, SHL 14.6–15.5 mm, TL/SHL ratio 99.3–99.4%, N = 3); and relatively more webbing between toes, male I2 – –2 II2 – –3– III2 1/2–3 1/2 IV3 1/2– 2V (vs. less, male I2 – –2– II2 – – 3–III 2–3 2/3 IV3 2/3– 2V). Fejervarya neilcoxi differs from F. manoharani by its prominently granular dorsal skin with spinular projections (vs. glandular with interrupted linear warts); snout subovoid in dorsal view (vs. rounded) and obtuse in lateral view (vs. vertical); relatively larger snout-vent size, male SVL 32.0– 33.3 mm, N = 3 (vs. smaller, male SVL 28.1–30.0 mm, N = 4); inter upper eyelid width relatively wider than upper eyelid width, male IUE 1.8–2.1 mm, UEW 2.5–2.9 mm, IUE/UEW ratio 72.0–75.0%, N = 3 (vs. relatively narrower, male IUE 1.7–2.0 mm, UEW 3.0 mm, IUE/UEW ratio 56.7–66.7%, N = 4); forearm length relatively longer than hand length, male FAL 6.1–6.2 mm, HAL 7.1–7.4 mm, FAL/HAL ratio 83.8–86.1%, N = 3 (vs. relatively shorter, male FAL 5.1–5.4 mm, HAL 6.4–6.9 mm, FAL/HAL ratio 76.8–79.7%, N = 4); thigh length relatively shorter than shank length, male TL 14.0– 14.5 mm, SHL 15.3–15.8 mm, TL/SHL ratio 91.5–92.2%, N = 3 (vs. relatively longer or nearly equal, male TL 12.9–13.5 mm, SHL 13.2–13.8 mm, TL/SHL ratio 96.3 – 99.2%, N = 4); and relatively less webbing between toes, male I2 – –2 II2 – –3– III2 1/2–3 1/2 IV3 1/2– 2V (vs. more, male I2–2 II2 – – 3–III 2–3 1/3 IV3 1/3– 2V, specifically the third toe webbing upto the first subarticular tubercle on the outside and fourth toe webbing extending closer to the second subarticular tubercle on either side). Since Fejervarya neilcoxi is found in the same geographical region as Fejervarya parambikulamana (Rao 1937), for which the type specimen is now lost (Dubois 1984), we also compared this new species with the original description of Rana (Tomopterna) parambikulamana Rao 1937. Fejervarya neilcoxi differs from F. parambikulamana by its relatively smaller snout-vent size, male SVL 32.0– 33.3 mm, N = 3 (vs. larger, male “From snout to vent 39.00 mm”, N = 1); prominently granular dorsal skin with spinular projections (vs. “skin smooth above” and “no granulation on any part of the body”); head wider than long, male HW 11.9–12.1 mm, HL 11.4–11.7 mm, N = 3 (vs. head “distinctly longer than broad”, HW “11.50” mm, HL “15.00” mm, N = 1); snout nearly equal to the diameter of the eye, male SL 4.2–4.3 mm, EL 4.1–4.2 mm, N = 3 (vs. “longer than the eye”, SL “6.50” mm, EL “5.00” mm, N = 1); first finger longer than the second, FL I 3.6 mm, FL II 2.9 mm, N = 1 (vs. “first nearly equal to the 2nd”, FL I “6.00 mm”, FL II “ 5.75 mm ”, N = 1); and fourth finger length considerably shorter than the diameter of the eye, FL IV 2.6 mm, EL 4.2 mm, N = 1 (vs. “fourth digit equals the diameter of the eye”, FL IV 5.0 mm, EL 5.0 mm, N = 1). Based on the original description and the accompanying illustration (Rao 1937, Pl. XXI, Fig. 1), F. parambikulamana is likely to be a member of the Fejervarya nilagirica group. Description of holotype (measurements in mm). Adult male (SVL 33.3), rather stout; head wider than long (HW 12.1, HL 11.7); snout subovoid in dorsal view and obtuse in lateral view, its length (SL 4.3) nearly equal to horizontal diameter of eye (EL 4.2); loreal region acute with rounded canthus rostralis; interorbital space flat, narrower (IUE 2.1) than upper eyelid (UEW 2.9) and internarial distance (IN 3.0); nostril nearly as close to eye (EN 2.1) as to tip of snout (NS 2.0); tympanum (TYD 1.6) 38.1% of eye diameter (EL 4.2); tympanum-eye distance (TYE 1.4), 87.5% of the tympanum diameter (TYD 1.6); supratympanic fold well developed, extends from posterior corner of eye to near the shoulder; vomerine ridge present, bearing small teeth, at an angle of 45° to the body axis, as close to choanae as to each other; tongue moderately large, emarginated, bearing no median lingual process; rictal gland present at labial commissure of the mouth. Arms short, forearm length (FAL 6.2) shorter then hand length (HAL 7.4); relative length of fingers IV<II<I<III (FL I 3.6, FL II 2.9, FL III 4.5, FL IV 2.6); finger tips rounded, slightly enlarged without discs, fingers without fringes, webbing between fingers absent; subarticular tubercles prominent, circular; one distinct palmar tubercle, oval, bifid; supernumerary tubercles absent. Hind limbs short, thigh (TL 14.5) shorter than shank (SHL 15.8) and foot (FOL 16.9), distance from the base of tarsus to the tip of toe IV (TFOL 22.7); toes long, relative length of toes I<II<V<III<IV; toe tips rounded, slightly enlarged without discs, toes without fringes, webbing between toes small: I2 – –2 II2 – –3– III2 1/2–3 1/2 IV3 1/ 2– 2V; inner toe length (ITL 2.8); subarticular tubercles prominent, all present, circular; inner metatarsal tubercle prominent, shovel-shaped (IMT 1.9); outer metatarsal tubercle small (OMT 0.7), rounded; supernumerary tubercles absent. Skin of snout shagreened to prominently granular, upper eyelids prominently tuberculate, anterior and posterior parts of back, and upper and lower parts of flank shagreened to prominently granular with spinular projections; interrupted inverse V-shaped ridge on center of dorsum; dorsal surfaces of forelimb, thigh and shank shagreened with scattered spinular projections. Ventral surface of throat, chest, belly and limbs shagreened, anterior part of thigh sparsely granular; fejervaryan line present on both sides of the belly (Fig. 12). Colour of holotype. In life. Snout, upper eyelids and anterior and posterior parts of back greyish-brown with prominent blackish-brown blotches (Fig. 12 A), upper and lower lip with faint alternate brown and light grey cross bands; tympanum light grey; flanks light grey with scattered dark grey mottling; forelimbs and hind limbs light brown with dark brown transverse bands; groin off-white with faint reticulations; anterior part of thigh light grey with greyish-brown reticulations; webbing light brown. Ventral surface of throat light flesh red with two lateral black calling patches; belly white; forearm and foreleg light flesh red. In preservation. Dorsum dark grey with blackish-grey blotches, forelimbs and hind limbs light greyish-brown dark greyish-brown transverse bands, posterior part of thigh greyish-brown with faint dark brown reticulations. Ventral surface of throat light grey with two lateral black calling patches on either side; belly off-white (Fig. 12). Variations. Morphometric data from three adult males and two adult females, including the holotype, is given in Table 7. Colour in preservation. ZSI/WGRC/V/A/953: dorsum light grey with dark grey blotches; ZSI/WGRC/ V/A/954 and ZSI/WGRC/V/A/955: ventral surface of throat with grey speckles. Secondary sexual characters. Male: calling patches on either side of the throat. Female (ZSI/ WGRC /V/A/ 955): pigmented eggs present (diameter 1.5 ± 0.3 mm, N = 15). Distribution and natural history. Fejervarya neilcoxi sp. nov. is currently known only from its type locality Parambikulam, south of Palghat gap in the Western Ghats state of Kerala (Fig. 3). The type series was observed near roadside vegetation with temporary pools of water. The specific site was close to a large moss-covered rock cutting surrounded with primary forest. Calling males were found close to water puddles and they stopped calling with any slight movement around them. Collections were made between 20:00–21:00 hours.Published as part of Garg, Sonali & Biju, S. D., 2017, Description of four new species of Burrowing Frogs in the Fejervarya rufescens complex (Dicroglossidae) with notes on morphological affinities of Fejervarya species in the Western Ghats, pp. 451-490 in Zootaxa 4277 (4) on pages 482-485, DOI: 10.11646/zootaxa.4277.4.1, http://zenodo.org/record/82983
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