Investigation of commuting Hamiltonian in quantum Markov network

Graphical Models have various applications in science and engineering which include physics, bioinformatics, telecommunication and etc. Usage of graphical models needs complex computations in order to evaluation of marginal functions,so there are some powerful methods including mean field approximation, belief propagation algorithm and etc. Quantum graphical models have been recently developed in context of quantum information and computation, and quantum statistical physics, which is possible by generalization of classical probability theory to quantum theory. The main goal of this paper is preparing a primary generalization of Markov network, as a type of graphical models, to quantum case and applying in quantum statistical physics.We have investigated the Markov network and the role of commuting Hamiltonian terms in conditional independence with simple examples of quantum statistical physics.Comment: 11 pages, 8 figure

Interfering trajectories in experimental quantum-enhanced stochastic simulation

Simulations of stochastic processes play an important role in the quantitative sciences, enabling the characterisation of complex systems. Recent work has established a quantum advantage in stochastic simulation, leading to quantum devices that execute a simulation using less memory than possible by classical means. To realise this advantage it is essential that the memory register remains coherent, and coherently interacts with the processor, allowing the simulator to operate over many time steps. Here we report a multi-time-step experimental simulation of a stochastic process using less memory than the classical limit. A key feature of the photonic quantum information processor is that it creates a quantum superposition of all possible future trajectories that the system can evolve into. This superposition allows us to introduce, and demonstrate, the idea of comparing statistical futures of two classical processes via quantum interference. We demonstrate interference of two 16-dimensional quantum states, representing statistical futures of our process, with a visibility of 0.96 $\pm$ 0.02.Comment: 9 pages, 5 figure

Effect of psychological training on self-esteem and intelligence quotient of children and youngsters

هدف اصلی این پژوهش افزایش عزت نفس فرزندان کارکنان بهداشتی با استفاده از آموزش های روانشناختی بود. ابتدا کلیه کارکنان واجد شرایط (دارای فرزندان 7 تا 15 ساله) شناسایی و سپس از بین 123 خانوار موجود بطور تصادفی 89 خانوار با مجموع 150 نفر از کودکان و نوجوانان انتخاب گردیدند این افراد بطور تصادفی به دو گروه تجربی و شاهد تقسیم شدند. بعد از ارائه آموزش های روانشناختی به مادران و فرزندان آنها در گروه تجربی، مجموعا 29 نفر (16 نفر گروه تجربی و 13 نفر گروه شاهد) به علت عدم مراجعه برای پس آزمون و شرکت در کلاس از مطالعه حذف شدند و 121 نفر (59 نفر گروه تجربی و 62 نفر گروه شاهد) مورد بررسی نهایی قرار گرفتند. در این پژوهش از آزمون هوشی ریون و آزمون عزت نفس آیزنک استفاده شد. بررسی نتایج پژوهش نشان داد که ارائه آموزش های روانشناختی به کودکان و نوجوانان و مادران آنها در افزایش عزت نفس کودکان و نوجوانان موثر است. همچنین همبستگی معنی داری بین نمره های عزت نفس و هوشبهر کودکان و نوجوانان بدست آمد. اما پس از ارائه آموزش های روانشناختی در هوشبهر کودکان و نوجوانان تفاوت معنی داری مشاهده نگردید. مقایسه هوشبهر کودکان و نوجوانان در دو گروه سنی 7 تا 10 ساله و 11 تا 15 ساله نشان داد که تفاوت معنی داری در هوشبهر دو گروه وجود دارد، اما در نمره های عزت نفس دو گروه تفاوت معنی داری مشاهده نگردید. نتایج این پژوهش نشان داد که ارائه آموزش های روانشناختی به کودکان و نوجوانان و مادران آنها بویژه در سنین دبستانی در رشد و شخصیت کودکان و بهداشت روانی خانواده موثر است

Single-shot quantum memory advantage in the simulation of stochastic processes

Stochastic processes underlie a vast range of natural and social phenomena. Some processes such as atomic decay feature intrinsic randomness, whereas other complex processes, e.g. traffic congestion, are effectively probabilistic because we cannot track all relevant variables. To simulate a stochastic system's future behaviour, information about its past must be stored and thus memory is a key resource. Quantum information processing promises a memory advantage for stochastic simulation that has been validated in recent proof-of-concept experiments. Yet, in all past works, the memory saving would only become accessible in the limit of a large number of parallel simulations, because the memory registers of individual quantum simulators had the same dimensionality as their classical counterparts. Here, we report the first experimental demonstration that a quantum stochastic simulator can encode the relevant information in fewer dimensions than any classical simulator, thereby achieving a quantum memory advantage even for an individual simulator. Our photonic experiment thus establishes the potential of a new, practical resource saving in the simulation of complex systems

Testing the reality of Wigner's friend's observations

Does quantum theory apply at all scales, including that of observers? A resurgence of interest in the long-standing Wigner's friend paradox has shed new light on this fundamental question. Here---building on a scenario with two separated but entangled "friends" introduced by Brukner---we rigorously prove that if quantum evolution is controllable on the scale of an observer, then one of the following three assumptions must be false: "No-Superdeterminism", "Locality", or "Absoluteness of Observed Events" (i.e. that every observed event exists absolutely, not relatively). We show that although the violation of Bell-type inequalities in such scenarios is not in general sufficient to demonstrate the contradiction between those assumptions, new inequalities can be derived, in a theory-independent manner, which are violated by quantum correlations. We demonstrate this in a proof-of-principle experiment where a photon's path is deemed an observer. We discuss how this new theorem places strictly stronger constraints on quantum reality than Bell's theorem.Comment: In v1, v2 we claimed to give the first rigorous proof of Brukner's theorem, interpreting his "Observer Independent Facts" assumption to be weaker than what he formalized. This was inaccurate (Brukner's theorem follows from his assumptions) and obscured the significantly stronger implications of our theorem. In v3 we name the weaker assumption in our theorem "Absoluteness of Observed Events

Nonlocality activation in a photonic quantum network

Bell nonlocality refers to correlations between two distant, entangled particles that challenge classical notions of local causality. Beyond its foundational significance, nonlocality is crucial for device-independent technologies like quantum key distribution and randomness generation. Nonlocality quickly deteriorates in the presence of noise, and restoring nonlocal correlations requires additional resources. These often come in the form of many instances of the input state and joint measurements, incurring a significant resource overhead. Here, we experimentally demonstrate that single copies of Bell-local states, incapable of violating any standard Bell inequality, can give rise to nonlocality after being embedded into a quantum network of multiple parties. We subject the initial entangled state to a quantum channel that broadcasts part of the state to two independent receivers and certify the nonlocality in the resulting network by violating a tailored Bell-like inequality. We obtain these results without making any assumptions about the prepared states, the quantum channel, or the validity of quantum theory. Our findings have fundamental implications for nonlocality and enable the practical use of nonlocal correlations in real-world applications, even in scenarios dominated by noise.Comment: Main text and Supplementary Information. Comments welcom

Conclusive experimental demonstration of one-way Einstein-Podolsky-Rosen steering

Einstein-Podolsky-Rosen steering is a quantum phenomenon wherein one party influences, or steers, the state of a distant party's particle beyond what could be achieved with a separable state, by making measurements on one half of an entangled state. This type of quantum nonlocality stands out through its asymmetric setting, and even allows for cases where one party can steer the other, but where the reverse is not true. A series of experiments have demonstrated one-way steering in the past, but all were based on significant limiting assumptions. These consisted either of restrictions on the type of allowed measurements, or of assumptions about the quantum state at hand, by mapping to a specific family of states and analysing the ideal target state rather than the real experimental state. Here, we present the first experimental demonstration of one-way steering free of such assumptions. We achieve this using a new sufficient condition for non-steerability, and, although not required by our analysis, using a novel source of extremely high-quality photonic Werner states.Comment: Supplemental Material included in the documen