Theoretical physics questions answered Essay Example | Topics and Well Written Essays - 3750 words

Theoretical physics questions answered - Essay Example (see answer-3) The remaining questions are about the rest of the paper, it would be sufficient for me if you could quote a book and chapter where I could find an answer to the respective question: -page 5: what do you mean by "carry no energy or momentum however ha energy-momentum" This means that massless particles are meaningless in Newtonian mechanics because they carry no energy or momentum and cannot sustain any force. Now, the relativistic expression for energy and momentum which is: however allows for non-zero energy-momentum for a massless particle when and this requires |v| 1. Furthur, in order to relate the energy E and momentum p we can assume that the relation p2 = m2 is valid for m = 0, and so, a massless particle's energy E and momentum p are related by E = |p|. page 7: I do not understand the sentence: "mediator has to be given on-zero spin" This actually wants to say that in order to accommodate the observed properties of the long-range electromagnetic and gravitational interactions, we also need to give the mediator a on-zero spin. However, this is non-trivial. _ page 8: why does the P operator transform under the fundamental This is an intrinsic requirement in any space-time study dealing with real vector spaces. Here 'P' is the orthogonal parameter that is subject to fundamental representation whereas U(A) is the unitary parameter representing the Lorentz group. This stands for transformations of the vector space that preserve the length of vectors. There are two vectors having zero scalar product in one reference frame which will remain orthogonal in the rotated frame. Remember space-time is itself a fundamental dynamic variable. - page 9 : eq 14: it is not clear to me why it is sufficient to consider the... This means that massless particles are meaningless in Newtonian mechanics because they carry no energy or momentum and cannot sustain any force. Now, the relativistic expression for energy and momentum which is: however allows for non-zero energy-momentum for a massless particle when and this requires |v| 1. This actually wants to say that in order to accommodate the observed properties of the long-range electromagnetic and gravitational interactions, we also need to give the mediator a on-zero spin. However, this is non-trivial. This is an intrinsic requirement in any space-time study dealing with real vector spaces. Here 'P' is the orthogonal parameter that is subject to fundamental representation whereas U(A) is the unitary parameter representing the Lorentz group. This stands for transformations of the vector space that preserve the length of vectors. There are two vectors having zero scalar product in one reference frame which will remain orthogonal in the rotated frame. Remember space-time is itself a fundamental dynamic variable. The irreps corresponding to the massless particles are found using the irreps of the little group for the massless particles and thus this is a better option. This little group is actually isotropy group and is a subgroup of the Poincare. no "internal Yang-Mills index" ^a which in our case transforms under space-time SO(1,3) rather than internal

The relationship between China and Taiwan Essay Example | Topics and Well Written Essays - 500 words

The relationship between China and Taiwan - Essay Example The relationship has been frosty ever since. First, they disagree on the independence of Taiwan. Taiwan claims to be an independent state while China claims Taiwan is part of it. China has refused to grant Taiwan its independence and recognize its leaders. The people of mainland China insist that there is only a single China and that Taiwan is an indisputable part of it. They refer to the Hong Kong agreement of 1992 where both leaders had a consensus that recognized only one China. Taiwan, however, reject the existence of such an agreement. In 2011, the People’s Republic of China was admitted into the UN general assembly while Taiwan (Republic of China) was expelled. All that was because China refused to acknowledge its statehood. The tension between the two nations has created an ‘arms race’. China has deployed missiles along the Taiwan Strait. Both its amphibious and missile forces capabilities are modernized in preparation of any situation. Every time the Taiwanese inch closer towards independence, they get the backing of the US Neo conservatives. They see china as a potential military rival. Taiwan purchases its weapons from abroad, with the USA being the largest supplier. China has been objecting the sale of weapons by the USA to Taiwan (Council on Foreign Relations). However, despite their differences, the two nations have strong economic ties. Bilateral trade was $102 billion in 2007, up from just $8 billion in 1991 (Council on Foreign Relations). China has and still remains Taiwan’s biggest trading partner and approximately a third of all Taiwan’s export products were sold in China. Taiwanese investments in the mainland china are estimated to be $150 billion since 1998. Their excellent economic elation is boosted by an agreement between the two nations to allow insurers and banks to invest in both markets (Council on Foreign Relations). Taiwan’s president, Ma Ying-jeou, has tried to ease tensions with