WASHINGTON (AP) - President Barack Obama and India's new Prime Minister Narendra Modi are trying to put an optimistic face on the future of relations between India and the United States, amid lingering concerns that the close ties the two democracies once enjoyed have lost their luster.An Oval Office meeting Tuesday with Obama and Vice President Joe Biden was to be the centerpiece of Modi's two-day visit to the White House, where Modi was to be greeted with a formal arrival ceremony outside the West Wing upon his arrival.