{"title":"fq </m的LRS - Bianchi型弦宇宙学模型","authors":"Mukesh Kumar, Manvinder Singh, Mohit Bajaj, Hossam Kotb, Djeudjo Temene Hermann","doi":"10.1155/2023/7016804","DOIUrl":null,"url":null,"abstract":"<jats:p>In the current study, we studied a <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\">\n <mi>f</mi>\n <mfenced open=\"(\" close=\")\" separators=\"|\">\n <mrow>\n <mi>Q</mi>\n </mrow>\n </mfenced>\n </math>\n </jats:inline-formula>-gravitational, anisotropic, locally rotationally symmetric (LRS), Bianchi type-I spacetime universe. We have adopted the freely chosen function <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\">\n <mi>f</mi>\n <mfenced open=\"(\" close=\")\" separators=\"|\">\n <mrow>\n <mi>Q</mi>\n </mrow>\n </mfenced>\n <mo>=</mo>\n <mi>Q</mi>\n <mo>+</mo>\n <mi>α</mi>\n <msqrt>\n <mi>Q</mi>\n </msqrt>\n </math>\n </jats:inline-formula>, where <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\">\n <mi>α</mi>\n </math>\n </jats:inline-formula> is a model-free parameter. We assumed that the universe is filled with dusty string fluid and that the shear scalar (<jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M5\">\n <mi>σ</mi>\n </math>\n </jats:inline-formula>) and the expansion scalar (<jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M6\">\n <mi>θ</mi>\n </math>\n </jats:inline-formula>) are proportional to each other in order to solve field equations for the average Hubble parameter (<jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M7\">\n <mi>H</mi>\n </math>\n </jats:inline-formula>). The resultant Hubble function has been fitted with observational datasets <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M8\">\n <mi>H</mi>\n <mfenced open=\"(\" close=\")\" separators=\"|\">\n <mrow>\n <mi>z</mi>\n </mrow>\n </mfenced>\n </math>\n </jats:inline-formula> and SNe Ia datasets of apparent magnitude <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M9\">\n <mi>m</mi>\n <mfenced open=\"(\" close=\")\" separators=\"|\">\n <mrow>\n <mi>z</mi>\n </mrow>\n </mfenced>\n </math>\n </jats:inline-formula> in order to obtain the best fit values for the cosmological parameters. Utilizing these best fit values throughout the analysis, many cosmic phenomena are examined. We have investigated cosmographic coefficients such as <jats:inline-formula>\n <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M10\">\n <mi>H</mi>\n <mo>,</mo>\n <mi>q</mi>\n <mo>,</mo>\n <mi>j</mi>\n <mo>,</mo>\n <mi mathvariant=\"normal\">a</mi>\n <mi mathvariant=\"normal\">n</mi>\n <mi mathvariant=\"normal\">d</mi>\n <mtext> </mtext>\n <mi>s</mi>\n </math>\n </jats:inline-formula> to see if an accelerated transit phase dark energy model of the cosmos exists. Also, we have classified the dark energy models that are explored using Om diagnostic analysis; our universe model is a quintessential dark energy model. The age of the universe as it exists right now has been roughly calculated by the model.</jats:p>","PeriodicalId":43667,"journal":{"name":"Muenster Journal of Mathematics","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"LRS Bianchi Type-I String Cosmological Models in <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M1\\\">\\n <mi>f</mi>\\n <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\">\\n <mrow>\\n <mi>Q</mi>\\n </m\",\"authors\":\"Mukesh Kumar, Manvinder Singh, Mohit Bajaj, Hossam Kotb, Djeudjo Temene Hermann\",\"doi\":\"10.1155/2023/7016804\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<jats:p>In the current study, we studied a <jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M2\\\">\\n <mi>f</mi>\\n <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\">\\n <mrow>\\n <mi>Q</mi>\\n </mrow>\\n </mfenced>\\n </math>\\n </jats:inline-formula>-gravitational, anisotropic, locally rotationally symmetric (LRS), Bianchi type-I spacetime universe. We have adopted the freely chosen function <jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M3\\\">\\n <mi>f</mi>\\n <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\">\\n <mrow>\\n <mi>Q</mi>\\n </mrow>\\n </mfenced>\\n <mo>=</mo>\\n <mi>Q</mi>\\n <mo>+</mo>\\n <mi>α</mi>\\n <msqrt>\\n <mi>Q</mi>\\n </msqrt>\\n </math>\\n </jats:inline-formula>, where <jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M4\\\">\\n <mi>α</mi>\\n </math>\\n </jats:inline-formula> is a model-free parameter. We assumed that the universe is filled with dusty string fluid and that the shear scalar (<jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M5\\\">\\n <mi>σ</mi>\\n </math>\\n </jats:inline-formula>) and the expansion scalar (<jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M6\\\">\\n <mi>θ</mi>\\n </math>\\n </jats:inline-formula>) are proportional to each other in order to solve field equations for the average Hubble parameter (<jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M7\\\">\\n <mi>H</mi>\\n </math>\\n </jats:inline-formula>). The resultant Hubble function has been fitted with observational datasets <jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M8\\\">\\n <mi>H</mi>\\n <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\">\\n <mrow>\\n <mi>z</mi>\\n </mrow>\\n </mfenced>\\n </math>\\n </jats:inline-formula> and SNe Ia datasets of apparent magnitude <jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M9\\\">\\n <mi>m</mi>\\n <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\">\\n <mrow>\\n <mi>z</mi>\\n </mrow>\\n </mfenced>\\n </math>\\n </jats:inline-formula> in order to obtain the best fit values for the cosmological parameters. Utilizing these best fit values throughout the analysis, many cosmic phenomena are examined. We have investigated cosmographic coefficients such as <jats:inline-formula>\\n <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M10\\\">\\n <mi>H</mi>\\n <mo>,</mo>\\n <mi>q</mi>\\n <mo>,</mo>\\n <mi>j</mi>\\n <mo>,</mo>\\n <mi mathvariant=\\\"normal\\\">a</mi>\\n <mi mathvariant=\\\"normal\\\">n</mi>\\n <mi mathvariant=\\\"normal\\\">d</mi>\\n <mtext> </mtext>\\n <mi>s</mi>\\n </math>\\n </jats:inline-formula> to see if an accelerated transit phase dark energy model of the cosmos exists. Also, we have classified the dark energy models that are explored using Om diagnostic analysis; our universe model is a quintessential dark energy model. The age of the universe as it exists right now has been roughly calculated by the model.</jats:p>\",\"PeriodicalId\":43667,\"journal\":{\"name\":\"Muenster Journal of Mathematics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2023-06-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Muenster Journal of Mathematics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1155/2023/7016804\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Muenster Journal of Mathematics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1155/2023/7016804","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}