Tuesday, April 22, 2008
Male Voice Countdown And Then Techno Song
laws governing the world of elementary particles are based on the principle of symmetry. For example, the strong interactions respect the gauge symmetry SU (3) of color. Gluons carry the interactions between quarks which have a quantum number called color (nothing to do with actual colors!). The Lagrangian that describes these interactions is invariant under base change in the color group. All particles can adopt their own agreement locally. To do this each term of the Lagrangian must have a precise way.
The symmetries are postulated as the ultimate in the way we understand nature. This idea has always like a deep abyss. Symmetry postulate. The universe appears to be governed by principles of invariance can take bases for arbitrary local quantum numbers. This applies to the strong interactions, for the weak and the electromagnetic. In each case the quantum numbers change, and consequently, the symmetry group.
The big mystery remains to find a consistent and satisfactory construction of the quantization of General Relativity. The underlying symmetry group remains unknown, despite the conceptual developments in string theory. The gulf of understanding that laws correspond to symmetries deepens to know unlikely to reach even partial solution for our lives.
Thursday, April 3, 2008
Bang Bros Pre Paid Cards
principles of symmetry Shannon entropy of von Neumann entropy vs energy of man
Entropy is a figure of merit that quantifies the surprise. Has a classically built by Shannon and a quantum (von Neumann call).
Let's see how the Shannon entropy measures the surprise in a message a thousand bits. If the message is all zeros, it is enough to send the phrase "all zeros." If you should send 500 zeros followed by a few hundred, it would be advantageous to send this phrase rather than a thousand digits. If the message was completely random, we should send all the thousand digits.
The question is not trivial is to know how much we can compress a message that is not absolutely random. The answer to this question was elegantly obtained by Shannon. We presume that the probability for each digit to be 0 is that of being p_0 i 1 is 1-p_1 = p_0. Shannon entropy is defined as S_SH Suma_ =- (i = 0.1) (Log_2 p_i (p_i)). In the first case we have considered, p_0 p_1 = 1 and = 0, then the entropy is zero. No surprise there. In the random case, p_0 = p_1 = 1 / 2. Entropy worth S_SH = 1 which is its maximum value. Shannon showed that we can compress a message N bits in only M = N S_SH. It is a brutal outcome used in all compression algorithm for both communications and storage. For example, the "zip", "gzip" and so on are based on Lempel-Ziv algorithms that saturate the bound of Shannon.
The quantum world is more subtle. We can think of a complex system made up of many particles and wonder if the state is made of overlapping. To be more precise, we wonder if part of the system is "we surprised" to have correlations with the rest. Von Neumann entropy quantifies this fact. The construction is technically and just write in brackets the result (whether a state von Neumann is S_vN =- Tr (rho_A Log_2 rho_A). In this way we can quantify the quantum correlations of a system.
is a delicate matter to relate this entropy with the Bekenstein entropy for a black hole. It is extremely subtle and misunderstood.
The surprise is measurable.
I've always found a great concept.
Entropy is a figure of merit that quantifies the surprise. Has a classically built by Shannon and a quantum (von Neumann call).
Let's see how the Shannon entropy measures the surprise in a message a thousand bits. If the message is all zeros, it is enough to send the phrase "all zeros." If you should send 500 zeros followed by a few hundred, it would be advantageous to send this phrase rather than a thousand digits. If the message was completely random, we should send all the thousand digits.
The question is not trivial is to know how much we can compress a message that is not absolutely random. The answer to this question was elegantly obtained by Shannon. We presume that the probability for each digit to be 0 is that of being p_0 i 1 is 1-p_1 = p_0. Shannon entropy is defined as S_SH Suma_ =- (i = 0.1) (Log_2 p_i (p_i)). In the first case we have considered, p_0 p_1 = 1 and = 0, then the entropy is zero. No surprise there. In the random case, p_0 = p_1 = 1 / 2. Entropy worth S_SH = 1 which is its maximum value. Shannon showed that we can compress a message N bits in only M = N S_SH. It is a brutal outcome used in all compression algorithm for both communications and storage. For example, the "zip", "gzip" and so on are based on Lempel-Ziv algorithms that saturate the bound of Shannon.
The quantum world is more subtle. We can think of a complex system made up of many particles and wonder if the state is made of overlapping. To be more precise, we wonder if part of the system is "we surprised" to have correlations with the rest. Von Neumann entropy quantifies this fact. The construction is technically and just write in brackets the result (whether a state von Neumann is S_vN =- Tr (rho_A Log_2 rho_A). In this way we can quantify the quantum correlations of a system.
is a delicate matter to relate this entropy with the Bekenstein entropy for a black hole. It is extremely subtle and misunderstood.
The surprise is measurable.
I've always found a great concept.
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