Markets closed down on what became a sluggish trading day that tacked onto Monday's losses. One stock that broke out was Alphabet (GOOGL) after unveiling what it calls a monumental breakthrough in quantum technology. Walgreen's (WBA) got a big bump in its stock after saying it plans to sell itself to a private equity firm. Meanwhile, MongoDB (MDB) returned its rally and then some despite posting an earnings beat. Oliver Renick breaks down the day's biggest movers.