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نویسندگان: 

Lee Taejin

اطلاعات دوره: 
  • سال: 

    2023
  • دوره: 

    3
  • شماره: 

    2
  • صفحات: 

    31-40
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    38
  • دانلود: 

    0
چکیده: 

The holography principle relates the quantum gravity in the bulk, described by closed string, the gauge theory, described by open string on the boundary with certain asymptotic conditions. Thus, it is important to understand intimate relations between open string theory and closed string theory: In the present work we propose a cubic closed string field theory, introducing a double layer to describe the closed string world-sheet as an extension of the open string world-sheet of the Witten's cubic open string. We mapped the closed string world-sheet onto the complex plane, of which the lower half plane is completely covered by the extended part of the string world-sheet. Using the Green's function on the complex plane, evaluated the Polyakov string path integral, from which we extracted the Neumann functions and the vertex operators.

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نویسنده: 

EVAZZADEH BAROOG FARIBA

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    2
تعامل: 
  • بازدید: 

    166
  • دانلود: 

    0
چکیده: 

THE TECHNOLOGY HAS IMPROVED GREATLY IN THE LAST CENTURY BUT NOW, THE WORLD NEEDS PEACE MORE THAN ANYTHING. AND FOR PROGRESS IN THE FIELD OF ETHICS, AND ACHIEVE A BETTER LIFE, KNOW THE SECRETS OF THE UNIVERSE AND THE LAWS IS NECESSARY. SO WE ARE TRYING TO KNOW ONE OF THE SECRETS. IT SEEMS, IN ADDITION TO THE REWARDS AND PUNISHMENTS IN ANOTHER WORLD, THIS WORLD IS LIKE A PRE-WRITTEN PROGRAM THAT EVERY ACTION, THOUGHT AND WORD HAS TO FOLLOW ITS OWN RESULTS. THUS WHAT WE DO, WHAT WE SAY AND WHAT WE THINK, ONE DAY WILL RETURN TO US. THEREFORE, WE ARE TRYING TO LEARN ONE OF THESE SECRETS, ACCORDING TO THE QUR'AN, AND THE NARRATIONS AND SAYINGS, AND ALSO LOOK AT OTHER RELIGIONS, AND THEIR RELATIONSHIP TO THE PHYSICAL LAWS OF THE WORLD, IN THIS STUDY.

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اطلاعات دوره: 
  • سال: 

    1397
  • دوره: 

    18
  • شماره: 

    3
  • صفحات: 

    107-116
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    519
  • دانلود: 

    0
چکیده: 

یادداشت پژوهشییادداشت پژوهشیمتریک های ناهمسانگرد بیانچی نوع II، VIII و IX که از نظر فضایی یکسان و همگن است، و همچنین مدل های کیهان شناسی همسانگرد را می توان در نظریه گرانشی تانسور اسکالر پیشنهاد شده توسط سائز و بالستر (1986) به دست آورد. زمانی که منبع تانسور حرکتی انرژی، یک مایع چسبنده حجمی حاوی رشته های کیهانی یک بعدی است. تمام مدل های به دست آمده و ارائه شده در اینجا در حال گسترش، غیرچرخشی و سرعت بخش هستند. همچنین برخی از ویژگی های مهم مدل های به دست آمده مورد بحث قرار گرفته است. متن کامل این مقاله به زبان انگلیسی می باشد. لطفا برای مشاهده متن کامل مقاله به بخش انگلیسی مراجعه فرمایید.لطفا برای مشاهده متن کامل این مقاله اینجا را کلیک کنید.

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نویسندگان: 

پورحسن بهنام

اطلاعات دوره: 
  • سال: 

    1398
  • دوره: 

    9
  • شماره: 

    2 (پیاپی 21)
  • صفحات: 

    31-38
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    368
  • دانلود: 

    95
چکیده: 

در این مقاله، ما ضمن مروری به نسخه های مختلف گاز چپلیگین، به عنوان مدلی برای توصیف انرژی تاریک، به معرفی مدل تکامل یافته گاز چپلیگین می پردازیم (که برای اولین بار در اینجا معرفی می گردد) که می تواند پوشش دهنده تمام مدل های رایج قبلی باشد. انرژی تاریک به عنوان یک سیال فرض می شود که می تواند به صورت یک سیستم بس ذره ای در نظر گرفته شود. هدف اصلی این مقاله این است که نشان دهیم معادله حالت گاز چپلیگین تکامل یافته همانند معادله حالت گاز چپلیگین معمولی می تواند از نظریه ریسمان به دست آید.

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نویسندگان: 

Chakrabarty Manjari

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    17
  • شماره: 

    42
  • صفحات: 

    298-316
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    100
  • دانلود: 

    22
چکیده: 

Modern (theoretical) physics seems to be in deep crisis today as many of its core aspects are not empirically well-confirmed. Heated exchanges among physicists on the scientific status of physical theories with little or, at best, a tenuous connection to possible experimental tests is highly visible in the popular scientific literature. Some physicists (e.g., Carroll 2014, 2019; Ijjas et al., 2017) argue that science must discard empirical testability as one of its defining properties and the highly explanatory theories of present-day physics should be exempted from experimental testing, while others (e.g., Ellis & Silk 2014) spot in these arguments (for softening the testability or falsifiability requirement for modern physics) a dangerous tendency to undermine science. The philosopher of science who naturally draws most attention in these current debates is Karl Popper (1902-1994). His views, however, are often misrepresented in these debates. The prime objective of this paper is to explain how a more enlightened perspective on the ongoing debates can be obtained by a careful scrutiny of the Popperian criterion of falsifiability. As a first step in achieving this objective we will analyze the two major (conceptual) failures on which the current controversies rest. Our next step will be examining the controversial string theory to see whether the criteria of falsifiability is a ‘blunt instrument’ for determining its scientific status.

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اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    7
  • شماره: 

    -
  • صفحات: 

    1-7
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    359
  • دانلود: 

    0
چکیده: 

We have obtained and presented spatially homogeneous Bianchi types II, VIII, and IX string cosmological models with bulk viscosity in Nordtvedt's (Astrophys. J.161:1059, 1970) general scalar-tensor theory of gravitation with the help of a special case proposed by Schwinger. It is observed that only the bulk viscous cosmological model exists in the case of Bianchi type IX universe. Some important features of the models, thus obtained, have been discussed.

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اطلاعات دوره: 
  • سال: 

    1393
  • دوره: 

    14
  • شماره: 

    3
  • صفحات: 

    35-39
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    799
  • دانلود: 

    0
چکیده: 

VI 0 فضا زمان بیانچی نوع با ماده کوارک عجیب متصل به ابر فنری در نظریه تانسوری اسکالر گرانش نوردتودت با کمک حالت خاص مطرح شده توسط شوینگر به دست آمده است. معادلات میدان با استفاده از خاصیت ناهمگنی جهان در فضا زمان بیانچی نوع VI0 حل شده است. بعضی از خصوصیات مهم مدل به دست آمده، مورد بحث قرار می گیرد. متن کامل مقاله های این شماره به زبان انگلیسی می باشد، لطفا برای مشاهده متن کامل مقالات به بخش انگلیسی مراجعه فرمایید.لطفا برای مشاهده متن کامل این مقاله اینجا را کلیک کنید.

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    113-144
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    177
  • دانلود: 

    26
چکیده: 

One of the factors that can be the link between our intentions and actions and their external consequences is human agency, which indicates the conscious design and intentional execution of actions by the individual in order to influence future events.Objective and Method: This research with a developmental approach of psychometric method and method 1, examines the psychometric indices of the Human Factor Characteristics Scale using the classical theory of test score measurement and the graduated question-answer theory. The purpose of this study, which included high school students in Tehran, was selected by cluster sampling of 500 people as a sample size and statistical analysis was performed on 481 data. To collect the data, the ion Human Agent Characteristics Scale (2011) was used and the research questions were evaluated using IRTPRO and SPSS software.Results:The assumption of local independence based on Pearson x2 index was established by applying Simjima's calibrated question-answer theory and the assumption of being one-dimensional based on the analysis of multidimensional question-answer theory. Diagnosis parameters with question-answer approach and classical approach Test score Both item 25 approach had the lowest and item 2 had the highest diagnosis parameter. The answer thresholds for all the questions were so far apart that no option was covered by the other option, and the options were independently selected by individuals at intervals of theta. The total scale was calculated with Cronbach's alpha of 0.945, intentionality of 0.894, foresight of 0.780, self-reactivity of 0.871 and rethinking of 0.762. Also, the role of each item in internal consistency was investigated by the loop method, which all questions had a favorable role in internal consistency of this scale. The value of the validity coefficient obtained from the question-answer theory was obtained by marginal method for intentionality 0.92, forethought 0.85, self-reaction 0.91, rethinking 0.83..

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نویسندگان: 

SAHOO P.K. | MISHRA B.

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    82
  • شماره: 

    1
  • صفحات: 

    87-87
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    121
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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نویسندگان: 

SAHOO PRADYUMN KUMAR | MISHRA BIVUDUTTA

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    7
  • شماره: 

    7
  • صفحات: 

    1-5
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    314
  • دانلود: 

    0
چکیده: 

We have studied the plane symmetric cosmological solutions for quark matter coupled with the string cloud and domain walls in the context of Rosen’s (General Relativity and Gravitation 4: 435, 1973) bimetric theory. It is observed that, in this theory, string cloud and domain walls do not exist. As we know that, at the early stage of evolution of the universe, domain walls as well as cosmic strings do appear which lead to the formation of galaxies. Thus, it may be said that the bimetric relativity does not help to describe the early era of the universe.

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