TAILIEUCHUNG - Basic Theoretical Physics: A Concise Overview P37

Basic Theoretical Physics: A Concise Overview P37. This concise treatment embraces, in four parts, all the main aspects of theoretical physics (I . Mechanics and Basic Relativity, II. Electrodynamics and Aspects of Optics, III. Non-relativistic Quantum Mechanics, IV. Thermodynamics and Statistical Physics). It summarizes the material that every graduate student, physicist working in industry, or physics teacher should master during his or her degree course. It thus serves both as an excellent revision and preparation tool, and as a convenient reference source, covering the whole of theoretical physics. It may also be successfully employed to deepen its readers’ insight and. | 50 Production of Low and Ultralow Temperatures Third Law 375 At ultralow temperatures of this order of magnitude the phenomenon of Bose-Einstein condensation comes into play see Sect. . In this case the third law only plays a part at even lower temperatures where quantization of the translational energy would become noticeable at temperatures n2 kBT ---------- B 2MeSR2 where R describes the size scale of the sample and Meff may be the mass of a Na atom in the normal state above the Bose condensation or in the condensed phase an effective mass . Anyhow we should remind ourselves that at these low temperatures and the corresponding low particle numbers some 104 to 105 instead of 1023 one should work with the microcanonical ensemble not the canonical or grand canonical ones. However one should also remember that the basic temperature definition M y 3kT is also valid for microcanonical ensembles. 51 General Statistical Physics Formal Completion the Statistical Operator Trace Formalism Is it really necessary to diagonalize the Hamilton operator H of the system H Ej if one just wants to calculate the partition function Z T E e- lkj j of the system and obtain the thermodynamic potentials or thermal expectation values - E I - x x e kBT - 0T E Zt The answer to this rhetorical question is of course negative. Instead of diagonalizing the Hamiltonian we can make use of the so-called trace formalism. This approach is based on the definition trace A ffj A j j which is valid for every complete orthonormal1 basis. It is easy to show that the expression on the . of this equation the sum of the diagonal elements of the matrix Ai fi Arfj is invariant with respect to a base change. It therefore follows for example that Z T trace e H where e-pH is the operator which has in the base of the eigenfunctions of H a matrix representation with diagonal elements e r In another base it can also be defined by the power series 2 1 n. Hn. n 0 1 Orthonormality is not even necessary. .

TỪ KHÓA LIÊN QUAN
TAILIEUCHUNG - Chia sẻ tài liệu không giới hạn
Địa chỉ : 444 Hoang Hoa Tham, Hanoi, Viet Nam
Website : tailieuchung.com
Email : tailieuchung20@gmail.com
Tailieuchung.com là thư viện tài liệu trực tuyến, nơi chia sẽ trao đổi hàng triệu tài liệu như luận văn đồ án, sách, giáo trình, đề thi.
Chúng tôi không chịu trách nhiệm liên quan đến các vấn đề bản quyền nội dung tài liệu được thành viên tự nguyện đăng tải lên, nếu phát hiện thấy tài liệu xấu hoặc tài liệu có bản quyền xin hãy email cho chúng tôi.
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.