اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدلماذا هناك شيء بدلاً من الخالي؟
Why there is something rather than nothing (out of everything)?
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تأليف
A.O.Barvinsky
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تم إظهار أن الطرف الإجمالي المتعلق بالهندسات الإيوكليدية للمؤشر الكتلي الذي تم الاقتراح حديثا للكون يصف مجموعة ميكروكانونيكال في الكوسمولوجيا الكمية. يعبر هذا المجموعة عن توزيع متساوي (بوزن واحد) في المساحة الفاصلة للمتغيرات الفعلية الحقيقية، ولكن من حيث الهندسة الزمنية المرئية فإنها متحسسة حول النقاط الشطرية المعقدة التي تم الحصول عليها حديثا في المبادئ الكوسمولوجية المحدودة إلى نطاق محدد من الثابت الكوسمولوجي المبكر. يتحول الكوسمولوجيات التضخمية التي تنتجها هذه المبادئ في المراحل المتأخرة من التوسع إلى التسارع الذي يمكن الوصول إليه على مستوى الطاقة المنخفضة ضمن مفهوم الأبعاد الإضافية التي تتحول ديناميكيا. وبالتالي، جنبا إلى جنب مع النطاق المحدود من الثابت الكوسمولوجي المبكر، يقترح هذا المجموعة الكوسمولوجية آلية تقييد ساحة الفراغات الخيطية وحلاً محتملاً لمشكلة الطاقة المظلمة في شكل تحلل نزولي قريب من التوازن للدولة الميكروكانونيكالة للكون.
The path integral over Euclidean geometries for the recently suggested density matrix of the Universe is shown to describe a microcanonical ensemble in quantum cosmology. This ensemble corresponds to a uniform (weight one) distribution in phase space of true physical variables, but in terms of the observable spacetime geometry it is peaked about complex saddle-points of the {em Lorentzian} path integral. They are represented by the recently obtained cosmological instantons limited to a bounded range of the cosmological constant. Inflationary cosmologies generated by these instantons at late stages of expansion undergo acceleration whose low-energy scale can be attained within the concept of dynamically evolving extra dimensions. Thus, together with the bounded range of the early cosmological constant, this cosmological ensemble suggests the mechanism of constraining the landscape of string vacua and, simultaneously, a possible solution to the dark energy problem in the form of the quasi-equilibrium decay of the microcanonical state of the Universe.
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