Answer:
No.
There are two main theories for why it would help unemployment. First, that more free cash for the rich will increase their use of products and services, thus increasing demand, and causing companies to hire. However, the rich (by definition) tend to save and invest most of their money, whereas the poor are the spenders and consumers (they don't hang on to their funds). So tax breaks for the rich are not an effective driver for consumption, demand, or productivity. Tax breaks for the poor are far more likely to be spent immediately, generating increased demand for products and services, and driving increased employment.
The second theory behind tax breaks for the wealthy suggests that more tax breaks will leave the wealthy with more money to reinvest in American companies. At a small business level, greater availability of investment capital can indeed enable increased hiring. However, for large, wealthy, and institutional investors, money is moved between stocks in large, publicly traded companies, bonds, and money market accounts. For these investments, increased capital does not drive increased hiring, as publicly traded companies typically have easier access to capital for things like personnel.
The final (non-economic) theory behind tax breaks for the wealthy is the notion that they've rightfully earned the money, and it's wrong to take it away and give it to someone who hasn't been as successful. However, the poor are pretty consistently having huge portions of their income taken and given to the rich in the form of late fees, higher interest rates, overdraft charges, and debit card fees. Also consider that a simple traffic ticket for expired registration (something the wealthy need never worry about) can easily set a poor person back by six months worth of disposable income. For a CEO making $11 million a year, this would be equivalent to getting pulled over and fined $5 million for old tags. And none of these things result in increased hiring.