Quantum Coursework Example | Topics and Well Written Essays - 1000 words

Quantum - Coursework Example Consequently, LDA is generally related to functionals, which are based on HEG approximation. LDA are implemented in realistic systems measurements and calculations (for example, molecules and solids). In a general view, for a spin-unpolarized system, â€Å"LDA for the exchange-correlation energy is the following where  ?  refers to the  electronic density  and  ?xc, the exchange-correlation energy concentration, is a function of the density. The exchange-correlation energy is split into exchange and correlation terms in a linear view: thus separate expressions for  Ex  and  Ec  are defined. Separate expressions known for the correlation density lead to numerous different approximations for  ?c†. (Parr and Weitao, 1994) LDA is a part of any approximate exchange-correlation functional. Its main function is to â€Å"replicate direct results of the HEG for non-varying densities† (Parr and Weitao 1994, p. 35). As a result, LDA is often mentioned as an exp licit component of such kind of functional. The Perdew-Burke-Ernzerhof (PBE) Modern scientists and researchers are greatly concerned about updating GGA functionals in their implementation in molecules and solids. ... Currently, accents in â€Å"generalized gradient approximations are shifted toward the description of free-atom energies† (Perdew et al, 2008). A group of scientists, Perdew et al (2008) have transformed and â€Å"adapted the Perdew-Burke-Ernzerhof generalized gradient approximation that updates equilibrium characteristics of dense solids and their surfaces† (Perdew et al, 2008). It is relevant to underline that the Perdew-Burke-Ernzerhof is a widely-used tool in solid state calculations. Consequently, a relevant note is that PBE is currently transformed with regard to GGA implementing both the density and its gradient at every space point (Perdew et al, 2008). If to correlate both concepts GGA and PBE, it will be clearly seen that GCA counterbalances â€Å"computational efficiency, numerical accuracy, and reliability† (Perdew et al 2008, p. 4068). Moreover, â€Å"PBE refers to the demands of quantum chemistry and solid-state physics† (Perdew et al 2008, p . 4068). Modern scientists think that it is necessary to ‘widen horizons’ of PBE implementation. Thus during the last decade it has been found out that â€Å"PBE reduces the chronic overbinding of the local spin density approximation (LSDA) [1], but, while LSDA often slightly underestimates equilibrium lattice constants by about 1%, PBE usually overestimates them by about the same amount† (Perdew et al 2008, p. 4070). Moreover, another important point of PBE properties is its equilibrium properties (e.g. bulk moduli, phonon frequencies, magnetism, and ferroelectricity). The abovementioned properties are susceptible to the lattice constant; thus they are ‘overcorrected’ by PBE (Perdew et al, 2008). Moreover, in spite of the fact that LSDA defines low

Mortality and the Meaning of Life Research Paper

Mortality and the Meaning of Life - Research Paper Example No one can calculate the exact time of when it will strike. Life has become a hectic burden for the common man. It has become a constant headache of keeping up with the payment of bills. That is all there is to life for most people on earth today. Relations have become secondary, values have become obsolete. The only thing that really matters is money. Money is the new god. But we have miserably faced to realize the most valuable commodity of all; time. There is extensive literature on the management of time. But the major part of it concerns with making the most monetary benefit out of it. We are living an illusion of life. The real essence of life has been buried deep beneath this disturbing rush on earth that we are a part of. Science says that a normal human being becomes aware of death normally around the age of 7 (Landau, 2011). But it is hard to tell when he becomes truly ‘aware’ of it. You don’t expect to die when going out for work in the morning or when coming to dining table for dinner, to be honest, the thought of dying hardly crosses our minds all day long, unless of course you love to listen to the news. You, me, we have all lost ourselves in the fast flow of time. It takes just a moment to stop and analyze whether we are passing through this life or is life passing us by. No one, sadly, has that moment to stop and procrastinate in today’s fast paced world. ... The topic of this essay forced me into a deeper contemplation of death than I have ever delved upon it previously. In my research over the topic, I read accounts of people who were diagnosed with fatal diseases and how the revelation changed and constructed their views about the meaning of life and its purpose (zoom, 2009). I learned that mortality plays the central role in giving our lives meaning. Almost all the people whose accounts I read had the same common realization, i.e. live completely in your today and for your today. They felt like that because they weren’t certain of whether they would live to see the next day or not. They wanted to live to their fullest in that very moment that they possessed, not being sure of even the next moment. That made me think; am I sure of my next moment? The answer is no. Life and death are the most unpredictable of all things we know. We witness people dying in their bedrooms and we also hear of people surviving fatal fires. So no, I d on’t know if I even have any time left after I finish this essay. Should we turn pessimistic over this fact and start living in fear of the inevitable. Religions of the world will teach you to do so, to fear your day of judgment if you believe in one, or to fear the consequences of your action after death. But the concept of mortality made me realize that the only thing I have to be fearful of is my ‘now’, to be fearful of the consequences of my actions that I am undertaking right now. There is an inherent beauty to the unpredictability of death. Since you are not aware of when it might arrive, you feel like you can always amend your ways or make right any wrong you might have done. At the same time, you are aware that you have to accomplish whatever gives you the most