High-Fidelity Two-Qubit Gates Using a Microelectromechanical-System-Based Beam Steering System for Individual Qubit Addressing.

In a large scale trapped atomic ion quantum computer, high-fidelity two-qubit gates need to be extended over all qubits with individual control. We realize and characterize high-fidelity two-qubit gates in a system with up to four ions using radial modes. The ions are individually addressed by two tightly focused beams steered using microelectromechanical system mirrors. We deduce a gate fidelity of 99.49(7)% in a two-ion chain and 99.30(6)% in a four-ion chain by applying a sequence of up to 21 two-qubit gates and measuring the final state fidelity. We characterize the residual errors and discuss methods to further improve the gate fidelity towards values that are compatible with fault-tolerant quantum computation.

Understanding Prosodic Focus Marking in Mandarin Chinese: Data from Children and Adults.

This study investigated whether Mandarin speakers interpret prosodic information as focus markers in a sentence-picture verification task. Previous production studies have shown that both Mandarin-speaking adults and Mandarin-speaking children mark focus by prosodic information (Ouyang and Kaiser in Lang Cogn Neurosc 30(1-2):57-72, 2014; Yang and Chen in Prosodic focus marking in Chinese four-and eight-year-olds, 2014). However, while prosodic focus marking did not seem to affect sentence comprehension in adults Mandarin-speaking children showed enhanced sentence comprehension when the sentence focus was marked by prosodic information in a previous study (Chen in Appl Psycholinguist 19(4):553-582, 1998). The present study revisited this difference between Mandarin speaking adults and children by applying a newly designed task that tested the use of prosodic information to identify the sentence focus. No evidence was obtained that Mandarin-speaking children (as young as 3 years of age) adhered more strongly to prosodic information than adults but that word order was the strongest cue for their focus interpretation. Our findings support the view that children attune to the specific means of information structure marking in their ambient language at an early age.

Children's comprehension of plural predicate conjunction.

Previous developmental studies of conjunction have focused on the syntax of phrasal and sentential coordination (Lust, 1977; de Villiers, Tager-Flusberg & Hakuta, 1977; Bloom, Lahey, Hood, Lifter & Fiess, 1980, among others). The present study examined the flexibility of children's interpretation of conjunction. Specifically, when two predicates that can apply simultaneously to a single individual are conjoined in the scope of a plural definite (The bears are big and white), conjunction receives a Boolean, intersective interpretation. However, when the conjoined predicates cannot apply simultaneously to an individual (The bears are big and small), conjunction receives a weaker 'split' interpretation (Krifka, 1990; Lasersohn, 1995; Winter, 1996). Our experiments reveal that preschool-aged children are sensitive to both intersective and split interpretations, and can use their lexical and world knowledge of the relevant predicates in order to select an appropriate reading.

Wh-Questions, Universal Statements and Free Choice Inferences in Child Mandarin.

This study investigated 5-year-old Mandarin-speaking children's comprehension of wh-questions, universal statements and free choice inferences. Previous research has found that Mandarin-speaking children assign a universal interpretation to sentences with a wh-word (e.g., shei 'who') followed by the adverbial quantifier dou 'all' (Zhou in Appl Psycholinguist 36:411-435, 2013). Children also compute free choice inferences in sentences that contain a modal verb in addition to a wh-word and dou (Zhou, in: Nakayama, Su, Huang (eds.) Studies in Chinese and Japanese language acquisition: in honour of Stephen Crain. John Benjamins Publishing Company, Amsterdam, pp 223-235, 2017). The present study used a Question-Statement Task to assess children's interpretation of sentences containing shei + dou, both with and without the modal verb beiyunxu 'was allowed to', as well as the contrast between sentences with shei + dou, which are statements for adults, versus ones with dou + shei, which are wh-questions for adults. The 5-year-old Mandarin-speaking child participants exhibited adult-like linguistic knowledge of the semantics and pragmatics of wh-words, the adverbial quantifier dou, and the deontic modal verb beiyunxu.

The Compositionality of Logical Connectives in Child Italian.

This paper investigates the interpretation that Italian-speaking children and adults assign to negative sentences with disjunction and negative sentences with conjunction. The aim of the study was to determine whether children and adults assign the same interpretation to these types of sentences. The Semantic Subset Principle (SSP) (Crain et al., in: Clifton, Frazer, Rayner (eds) Perspective on sentence processing, Lawrence Erlbaum, Hillside, 1994) predicts that children's initial scope assignment should correspond to the interpretation that makes sentences true in the narrowest range of circumstances, even when this is not the interpretation assigned by adults. This prediction was borne out in previous studies in Japanese, Mandarin and Turkish. As predicted by the SSP, the findings of the present study indicate that Italian-speaking children and adults assign the same interpretation to negative sentences with conjunction (conjunction takes scope over negation). By contrast, the study revealed that some children differed from adults in the interpretation they assigned to negative sentences with disjunction. Adults interpreted disjunction as taking scope over negation, whereas children were divided into two groups: one group interpreted disjunction as taking scope over negation as adults did; another group interpreted negation as taking scope over disjunction, as predicted by the SSP. To explain the findings, we propose that Italian-speaking children initially differ from adults as dictated by the SSP, but children converge on the adult grammar earlier than children acquiring other languages due to the negative concord status of Italian, including the application of negative concord to sentences with disjunction.

Differences in Scope Assignments for Child and Adult Speakers of Mandarin.

The present study used a Truth Value Judgment Task to investigate whether changes in sentence structure lead to corresponding changes in the assignment of scope relations by Mandarin-speaking children and adults. In one condition, participants were presented with ordinary negative sentences containing disjunction; this condition was designed to verify the existing claim that disjunction is a positive polarity item for adult speakers of Mandarin, but not for child speakers. In a second condition, participants were presented with negative sentences where the disjunction phrase was preposed from object position; this condition was designed to examine the extent to which changes in sentence structure can result in changes in scope assignments to negated disjunctions. The results indicate that the preposed disjunction phrase undergoes reconstruction for children, whereas reconstruction is blocked for adults. This finding also suggests that Mandarin-speaking children and adults exhibit different scope preferences for negated disjunctions, regardless of where the disjunction phrase appears in the surface syntax.

Dual temporal encoding mechanisms in human auditory cortex: Evidence from MEG and EEG.

Current hypotheses about language processing advocate an integral relationship between encoding of temporal information and linguistic processing in the brain. All such explanations must accommodate the evident ability of the perceptual system to process both slow and fast time scales in speech. However most cortical neurons are limited in their capability to precisely synchronise to temporal modulations at rates faster than about 50Hz. Hence, a central question in auditory neurophysiology concerns how the full range of perceptually relevant modulation rates might be encoded in the cerebral cortex. Here we show with concurrent noninvasive magnetoencephalography (MEG) and electroencephalography (EEG) measurements that the human auditory cortex transitions between a phase-locked (PL) mode of responding to modulation rates below about 50Hz, and a non-phase-locked (NPL) mode at higher rates. Precisely such dual response modes are predictable from the behaviours of single neurons in auditory cortices of non-human primates. Our data point to a common mechanistic explanation for the single neuron and MEG/EEG results and support the hypothesis that two distinct types of neuronal encoding mechanisms are employed by the auditory cortex to represent a wide range of temporal modulation rates. This dual encoding model allows slow and fast modulations in speech to be processed in parallel and is therefore consistent with theoretical frameworks in which slow temporal modulations (such as rhythm or syllabic structure) are akin to the contours or edges of visual objects, whereas faster modulations (such as periodicity pitch or phonemic structure) are more like visual texture.

The interpretation of logical connectives in Turkish.

This study investigated how Turkish-speaking children and adults interpret negative sentences with disjunction (English or) and ones with conjunction (English and). The goal was to see whether Turkish-speaking children and adults assigned the same interpretation to both kinds of sentences and, if not, to determine the source of the differences. Turkish-speaking children and adults were found to assign different interpretations to negative sentences with disjunction just in case the nouns in the disjunction phrase were marked with accusative case. For children, negation took scope over disjunction regardless of case marking, whereas, for adults, disjunction took scope over negation if the disjunctive phrases were case marked. Both groups assigned the same interpretation to negative sentences with conjunction; both case-marked and non-case-marked conjunction phrases took scope over negation. The findings are taken as evidence for a 'subset' principle of language learnability that dictates children's initial scope assignments.

Movement-related neuromagnetic fields in preschool age children.

We examined sensorimotor brain activity associated with voluntary movements in preschool children using a customized pediatric magnetoencephalographic system. A videogame-like task was used to generate self-initiated right or left index finger movements in 17 healthy right-handed subjects (8 females, ages 3.2-4.8 years). We successfully identified spatiotemporal patterns of movement-related brain activity in 15/17 children using beamformer source analysis and surrogate MRI spatial normalization. Readiness fields in the contralateral sensorimotor cortex began ∼0.5 s prior to movement onset (motor field, MF), followed by transient movement-evoked fields (MEFs), similar to that observed during self-paced movements in adults, but slightly delayed and with inverted source polarities. We also observed modulation of mu (8-12 Hz) and beta (15-30 Hz) oscillations in sensorimotor cortex with movement, but with different timing and a stronger frequency band coupling compared to that observed in adults. Adult-like high-frequency (70-80 Hz) gamma bursts were detected at movement onset. All children showed activation of the right superior temporal gyrus that was independent of the side of movement, a response that has not been reported in adults. These results provide new insights into the development of movement-related brain function, for an age group in which no previous data exist. The results show that children under 5 years of age have markedly different patterns of movement-related brain activity in comparison to older children and adults, and indicate that significant maturational changes occur in the sensorimotor system between the preschool years and later childhood.

Using event-related potentials to measure phrase boundary perception in English.

BACKGROUND: The closure positive shift (CPS) event related potential (ERP) is commonly used as a neural measure of phrase boundary perception in speech. The present study investigated whether the CPS was elicited by acoustic cues at phrase boundaries in English. ERPs were recorded when participants listened passively to sentences with either early or late phrase boundaries. RESULTS: The closure positive shift (CPS) ERP was elicited at both early and late phrase boundaries. However, the latency, amplitude, and scalp distribution of these passive CPS ERPs in English sentences differed to active CPS ERPs measured in non-English sentences in previous studies. CONCLUSIONS: These results show that acoustic cues at the phrase boundaries in English are sufficient to elicit the CPS, and suggest that different processes might be involved in the generation of the CPS in active and passive conditions.

Acquisition of the polarity sensitive item renhe 'any' in Mandarin Chinese.

The present study investigated Mandarin-speaking children's acquisition of the polarity sensitive item renhe 'any' in Mandarin Chinese. Like its English counterpart any, renhe can be used as a negative polarity item (NPI), or as a free choice (FC) item, and both the distribution and interpretation of renhe are governed by the same syntactic and semantic constraints as English any. Using a Truth Value Judgment Task, the present study tested five-year-old Mandarin-speaking children's comprehension of FC renhe in sentences containing the modal word neng 'can', and tested children's comprehension of NPI renhe in sentences containing the temporal conjunction zai…zhiqian 'before'. Most children demonstrated knowledge of the interpretation of both FC renhe and NPI renhe despite a paucity of relevant adult input. Like adults, however, Mandarin-speaking children do not use renhe frequently in ordinary conversation, due to the availability of alternative colloquial expressions (wh-pronouns) that also convey children's intended meanings.

Language and learning: the cognitive revolution at 60-odd.

Around the middle of the last century, the prevailing psychological paradigm of behaviourism was challenged by what is now known as the cognitive revolution. Behaviourists viewed learning as changes in patterns of behaviour through reinforcement. By contrast, advocates of the cognitive approach argued that such behavioural changes were outward manifestations of computational operations on mental representations. Here we consider the current state of the cognitive revolution, focusing on the two most contentious issues in the debate: language and learning. The cognitive approach has proved to be extremely fruitful in both fields. Although contemporary learning theory has almost completely embraced the cognitive approach, the study of language has witnessed a clear empiricist trend to revert back to a kind of neo-behaviourism. Many contemporary authors contend that language is a means of communication that is learned solely through the observation of external events, and culturally transmitted to successive generations. Here, we argue that learning and language can only be properly understood from a cognitive perspective, where the mind is conceived of as a biologically underpinned computational system. As is the case in learning theory, there is abundant evidence showing that language is subserved by an autonomous cognitive system in the mind. We conclude that the cognitive revolution has fundamentally changed our understanding of the mind.

Stable optical phase modulation with micromirrors.

We measure the motional fluctuations of a micromechanical mirror using a Michelson interferometer, and demonstrate its interferometric stability. The position stability of the micromirror is dominated by the thermal mechanical noise of the structure. With this level of stability, we utilize the micromirror to realize an optical phase modulator by simply reflecting light off the mirror and modulating its position. The resonant frequency of the modulator can be tuned by applying a voltage between the mirror and an underlying electrode. Full modulation depth of ±π is achieved when the mirror resonantly excited with a sinusoidal voltage at an amplitude of 11 V.

Are there universals of reading? We don't believe so.

There are universals of language; but is it also true, as the target article claims, that there are universals of reading? We believe there are no such universals, and invite others to refute our claim by providing a list of some universals of reading. If there are no universals of reading, there cannot be a universal model of reading.

Downward entailment in child Mandarin.

There are three hallmarks of core linguistic properties. First, they are expected to be manifested in typologically different languages. Second, they should unify superficially unrelated linguistic phenomena. Third, they are expected to emerge early in the course of language development, all things being equal (Crain, 1991). The present study investigates a candidate for a core linguistic property, namely the semantic property of downward entailment. We report the findings of two experimental studies of children's knowledge of downward entailment. These experiments explore two different aspects of downward entailment, in a study with Mandarin-speaking children. Taken together with previous research findings, the results of the present study support the conclusion that downward entailment is a core property of human languages.

Children's interpretation of disjunction in the scope of 'before': a comparison of English and Mandarin.

This study investigates three- to five-year-old children's interpretation of disjunction in sentences like 'The dog reached the finish line before the turtle or the bunny'. English disjunction has a conjunctive interpretation in such sentences ('The dog reached the finish line before the turtle and before the bunny'). This interpretation conforms with classical logic. Mandarin disjunction ('huozhe') can take scope over 'before' ('zai … zhiqian'), so the same sentence can mean 'The dog reached the finish line before the turtle or before the bunny (I don't know which)'. If children are guided by adult input in the acquisition of sentence meanings, English- and Mandarin-speaking children should assign different interpretations to such sentences. If children are guided by logical principles, then children acquiring either language should initially assign the conjunctive interpretation of disjunction. A truth-value judgment task was used to test this prediction and English- and Mandarin-speaking children were found to behave similarly.

Children's use of phonological information in ambiguity resolution: a view from Mandarin Chinese.

How do children develop the mapping between prosody and other levels of linguistic knowledge? This question has received considerable attention in child language research. In the present study two experiments were conducted to investigate four- to five-year-old Mandarin-speaking children's sensitivity to prosody in ambiguity resolution. Experiment 1 used eye-tracking to assess children's use of stress in resolving structural ambiguities. Experiment 2 took advantage of special properties of Mandarin to investigate whether children can use intonational cues to resolve ambiguities involving speech acts. The results of our experiments show that children's use of prosodic information in ambiguity resolution varies depending on the type of ambiguity involved. Children can use prosodic information more effectively to resolve speech act ambiguities than to resolve structural ambiguities. This finding suggests that the mapping between prosody and semantics/pragmatics in young children is better established than the mapping between prosody and syntax.

Children's knowledge of the quantifier dou in Mandarin Chinese.

The quantifier dou (roughly corresponding to English 'all') in Mandarin Chinese has been the topic of much discussion in the theoretical literature. This study investigated children's knowledge of this quantifier using a new methodological technique, which we dubbed the Question-Statement Task. Three questions were addressed: (i) whether young Mandarin-speaking children know that dou is a universal quantifier that quantifies over the elements to its left, (ii) whether they know that dou is an adverb of quantification (Q-adverb) which can (unselectively) bind any variable in its domain, and (iii) whether they know that dou can quantify over wh-words. The main finding was that, by age four, Mandarin-speaking children have the relevant knowledge. The results reflect the early availability of adult-like linguistic knowledge of dou-quantification.