郭光灿院士：甘坐冷板凳的研究生

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难得的李博士 做到这样确实很难！  
我读博期间，也小有发现，老板也是院士，在我毕业的时候还说人一生能有好的发现很难，建议我坚持做下去。可是那个时候已经根本无心再做下去，非常非常浮躁，主要原因还是自己从农村出来，家里很穷，研究生那点补贴根本微不足道，只想早点毕业赚钱贴补家用。现在回想起来，老板说的很对，就是遇到感兴趣的东西一定要深究，需要付出更多的时间和代价，甘心寂寞；但是也不完全对，动辄上百万乃至千万的课题，为何不能提高点研究生的待遇，以解决后顾之忧。分析一个人乃至整个社会的问题，还得从经济入手阿。

Private Capacity of Quantum Channels is Not Additive

Ke Li, Andreas Winter, XuBo Zou, and GuangCan Guo
Published 15 September 2009

Abstract
Recently there has been considerable activity on the subject of the additivity of various quantum channel capacities. Here, we construct a family of channels with a sharply bounded classical and, hence, private capacity. On the other hand, their quantum capacity when combined with a zero private (and zero quantum) capacity erasure channel becomes larger than the previous classical capacity. As a consequence, we can conclude for the first time that the classical private capacity is nonadditive. In fact, in our construction even the quantum capacity of the tensor product of two channels can be greater than the sum of their individual classical private capacities. We show that this violation occurs quite generically: every channel can be embedded into our construction, and a violation occurs whenever the given channel has a larger entanglement-assisted quantum capacity than (unassisted) classical capacity.

现在耐得住寂寞、不浮躁的人太少了

问题是这样的导师太少！

确实厉害啊 ~~~