Posts Tagged ‘time’

time

by MIKE MCRAE

For around a century it’s been thought that particles don’t have defined properties until we nail them down with a measurement.

That kind of quantum madness opens up a whole world of counter-intuitive paradoxes. Take this one, for example – it’s possible for a single particle to experience two sequences of events at the same time, making it impossible to know which came first.

Physicists from the University of Queensland designed a race course for light that forced a single particle to traverse two pathways at once, making it impossible to say in which order it completed a pair of operations.

In boring old everyday life you could roll a single ball down a ramp and have it ring bell A and then ring bell B. Or, if you’d prefer, you could roll it down another ramp and have it ring B before A.

If you want to get fancy you could even set up a rig so one bell causes the other bell to ring.

None of this is mind blowing, since we’re used to events in the Universe having a set order, where one thing precedes another in such a way that we presume an order of causation.

But nothing is so simple when we accept that reality is a blur of possibility prior to it being measured.

To demonstrate this, the physicists created a physical equivalent of something called a quantum switch, where multiple operations occur while a particle is in a superposition of all its possible locations.

Keeping it simple, the team set up a pathway that split apart and converged again in an interferometer, with access to each fork dependent on the polarisation of the light entering it.

Light waves travelling down each fork in the pathway would then merge and interfere to create a distinctive pattern depending on its properties.

In this particular case, the two light waves were actually the same photon taking both paths at the same time.

Before being measured, a photon can be either vertically or horizontally polarised. Or, more precisely, it’s polarised both vertical and horizontal at the same time until a measurement confirms one over the other.

Since this undefined photon’s polarisation is both vertical and horizontal, it enters both pathways, with the vertically polarised version of the photon barrelling down one channel and the horizontally polarised version heading down the second.

Following the two paths, the team had the quantum equivalent of those bells we mentioned earlier – in the form of lenses that subtly changed the shape of the photon.

The horizontal polarisation would hit ‘bell’ A before striking B, while the vertical polarisation would strike ‘bell’ B, and then A.

An analysis of the interference pattern of the reunited photon revealed signs of this mess of possible sequences.

On one hand, it’s easy to imagine two separate light particles – one horizontally polarised, the other vertically polarised – passing each lens in separate orders.

That’s not what happened, though. This was a single photon with two possible histories, neither of which set in reality until they’re measured.

While the events A and B were independent in this quantum switch, they could be linked to affect one another. A could cause B, or B could cause A … all depending on which history you wanted after the event.

Putting aside daydreams of travelling back in time to undo that big mistake (what were you thinking?!), this does have one possible practical application in the emerging field of quantum communications.

Transmitting photons down a noisy channel could be disastrous for their quantum information, quickly making a mess of their precious superposition. Sending them down channels fitted with a quantum switch, however, could in principle give the quantum information an opportunity to get through.

A paper the team published on the pre-peer review website arxiv.org back in July shows how a quantum switch applied to two noisy channels can allow a superposition to survive.

Whatever weird clockwork is going on in reality’s basement, we won’t pretend to understand it. But the very fact physicists are able to craft it into new technology is truly mindblowing in itself.

This research was published in Physical Review Letters.

https://www.sciencealert.com/quantum-switch-causation-superposition-applied-technology

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Stephen Hawking submitted the final version of his last scientific paper just two weeks before he died, and it lays the theoretical groundwork for discovering a parallel universe.

Hawking, who passed away on Wednesday aged 76, was co-author to a mathematical paper which seeks proof of the “multiverse” theory, which posits the existence of many universes other than our own.

The paper, called “A Smooth Exit from Eternal Inflation”, had its latest revisions approved on March 4, ten days before Hawking’s death.

According to The Sunday Times newspaper, the paper is due to be published by an unnamed “leading journal” after a review is complete.

ArXiv.org, Cornell University website which tracks scientific papers before they are published, has a record of the paper including the March 2018 update.

According to The Sunday Times, the contents of the paper sets out the mathematics necessary for a deep-space probe to collect evidence which might prove that other universes exist.

The highly theoretical work posits that evidence of the multiverse should be measurable in background radiation dating to the beginning of time. This in turn could be measured by a deep-space probe with the right sensors on-board.

Thomas Hertog, a physics professor who co-authored the paper with Hawking, said the paper aimed “to transform the idea of a multiverse into a testable scientific framework.”

Hertog, who works at KU Leuven University in Belgium, told The Sunday Times he met with Hawking in person to get final approval before submitting the paper.

https://www.sciencealert.com/stephen-hawking-submitted-a-paper-on-parallel-universes-just-before-he-died

Thanks to Kebmodee for bringing this to the It’s Interesting community.

By Jeffrey Bennett

It has been exactly 100 years since Albert Einstein presented his theory of general relativity to an audience of scientists on November 25, 1915. While virtually everyone has heard of Einstein and his theory, very few people have any idea of what the theory actually is.

This is a shame, not only because there is a great public thirst for understanding of it, but also because relativity is important, for at least four major reasons.

General relativity provides our modern understanding of space, time and gravity — which means it’s crucial to almost everything we do in physics and astronomy. For example, you cannot understand black holes, the expansion of the universe or the Big Bang without first understanding the basic ideas of relativity. Though few people realize it, Einstein’s famous equation E = mc2 is actually part of the theory of relativity, which means that relativity also explains how the sun shines and how nuclear power works.

A second reason everyone should know about relativity lies in the way it changes our perception of reality. Relativity tells us that our ordinary perceptions of time and space are not universally valid. Instead, space and time are intertwined as four-dimensional space-time.

In our ordinary lives, we perceive only three dimensions—length, width and depth—and we assume that this perception reflects reality. However, in space-time, the four directions of possible motion are length, width, depth and time. (Note that time is not “the” fourth dimension; it is simply one of the four.)

Although we cannot picture all four dimensions of space-time at once, we can imagine what things would look like if we could. In addition to the three spatial dimensions of space-time that we ordinarily see, every object would be stretched out through time. Objects that we see as three-dimensional in our ordinary lives would appear as four-dimensional objects in space-time. If we could see in four dimensions, we could look through time just as easily as we look to our left or right. If we looked at a person, we could see every event in that person’s life. If we wondered what really happened during some historical event, we’d simply look to find the answer.

To see why this is so revolutionary, imagine that you met someone today who deeply believed that Earth is the center of the universe. You would probably feel sorry for this person, knowing that his or her entire world view is based on an idea disproven more than 400 years ago.

Now imagine that you met someone who still believed that time and space are independent and absolute — which, of course, describes almost everyone — even though we’ve known that’s not the case for a century now. Shouldn’t we feel equally sorry for all who hold this modern misconception?

It seems especially unfortunate once you realize that the ideas of relativity are not particularly difficult to understand. Indeed, I believe we could begin teaching relativity in elementary school in much the same way that we teach young children about the existence of atoms, even though few will ever study quantum mechanics.

My third reason for believing relativity is important lies in what Einstein’s discovery tells us about human potential. The science of relativity may seem disconnected from most other human endeavors, but I believe Einstein himself proved otherwise. Throughout his life, Einstein argued eloquently for human rights, human dignity and a world of peace and shared prosperity. His belief in underlying human goodness is all the more striking when you consider that he lived through both World Wars, that he was driven out of Germany by the rise of the Nazis, that he witnessed the Holocaust that wiped out more than six million of his fellow Jews, and that he saw his own discoveries put to use in atomic bombs.

No one can say for sure how he maintained his optimism in the face of such tragedies, but I see a connection to his discovery of relativity. Einstein surely recognized that a theory that so challenged our perceptions of reality might have been dismissed out of hand at other times in history, but that we now live in a time when, thanks to the process that we call science, the abundant evidence for relativity allowed for its acceptance.

This willingness to make judgments based on evidence shows that we are growing up as a species. We have not yet reached the point where we always show the same willingness in all our other endeavors, but the fact that we’ve done it for science suggests we have the potential.

Finally, on a philosophical level, relativity is profound. Only about a month before his death in 1955, Einstein wrote: “Death signifies nothing … the distinction between past, present and future is only a stubbornly persistent illusion.” As this suggests, relativity raises interesting questions about what the passage of time really means.

Because these are philosophical questions, they do not have definitive answers, and you will have to decide for yourself what these questions mean to you. But I believe that one thing is clear. Einstein showed that even though space and time can independently differ for different observers, the four-dimensional space-time reality is the same for everyone.

This implies that events in space-time have a permanence to them that cannot be taken away. Once an event occurs, in essence it becomes part of the fabric of our universe. Every human life is a series of events, and this means that when we put them all together, each of us is creating our own, indelible mark on the universe. Perhaps if everyone understood that, we might all be a little more careful to make sure that the mark we leave is one that we are proud of.

So there you have it. Relativity is necessary to comprehend the universe as we know it, it helps us understand the potential we all share when we put our brains to work for the common good, and if we all understood it we might treat each other a little more kindly.

http://www.cnn.com/2015/11/25/opinions/bennett-einstein-theory-of-relativity/index.html

by John Haltiwanger

I woke up at 6 am this morning, three hours before I’m supposed to be in the office, and was still 10 minutes late to work.

This is pretty standard for me. I’m almost always a few minutes late. I don’t mean anything by it, and I certainly don’t think I deserve a different set of rules than everyone else — it’s just the way I am.

I wake up early and try to fill the time before I leave for the office with as many activities as possible: a short workout, breakfast, catching up on the news, daydreaming while struggling to put my socks on, etc.

I’ll look at the clock and think, “Oh, I still have plenty of time.” One or two tasks later, I’ve only got 40 minutes to get to work and a 45 minute commute.

This has been the case with every single job I’ve ever had and is typically true when it comes to social meetings as well. I’m habitually unpunctual, and apparently I’m not alone.

As management consultant Diana DeLonzor states:

Most late people have been late all their life, and they are late for every type of activity — good or bad.

Surprisingly little scientific research has been done on tardiness, but some experts subscribe to the theory that certain people are hardwired to be late and that part of the problem may be embedded deep in the lobes of the brain.

So if you’re chronically late, I feel for you and sympathize with the onslaught of criticism you likely receive on a consistent basis.

I know you’re not a lazy, unproductive, inconsiderate or entitled person. I know you’re not attempting to insult anyone by your tardiness.

Your lateness is simply a consequence of your psychology and personality — nothing more, nothing less.

With that said, while those of us who are continuously tardy should work to overcome this trait, there are also hidden benefits.

Chronically late people aren’t hopeless, they’re hopeful.

People who are continuously late are actually just more optimistic. They believe they can fit more tasks into a limited amount of time more than other people and thrive when they’re multitasking. Simply put, they’re fundamentally hopeful.

While this makes them unrealistic and bad at estimating time, it also pays off in the long-run in other ways.

Researchers have found optimism has a myriad of physical health benefits, from reducing stress and diminishing the risk of cardiovascular disease to strengthening your immune system.

Indeed, happiness and positivity have been linked to a longer life in general.

Maintaining a positive outlook is also vital to achieving personal success. Research shows happiness increases overall productivity, creativity and teamwork in the workplace.

All of this makes a great deal of sense, as a study conducted at San Diego State University has also connected lateness with Type B personalities, or people who tend to be more laid-back and easygoing.

In other words, people who are habitually late don’t sweat over the small stuff, they concentrate on the big picture and see the future as full of infinite possibilities.

Time is relative, learn to live in the moment.

We should also note punctuality is a relative concept. Time and lateness mean different things in different cultures and contexts.

In the United States, we often interpret lateness as an insult or a sign of a poor work ethic.

When people are late, it’s assumed they feel their time is more important or valuable. Americans believe time is money and money is time.

But if you head over to Europe, it’s almost as if the notion of time magically mutates each time you enter a new country.

In Germany, the land of perpetual efficiency, punctuality is of the utmost importance.

When Russian President Vladimir Putin was late to a meeting with German Chancellor Angela Merkel, for example, she left because that’s how Germans roll.

If you venture over to Spain, however, you’ll find time has taken a completely different character. The Spanish run by their own clock and are famous for eating dinner at 10 pm.

Sail on down to Latin America, and you’ll discover punctuality bears little to no importance.

The point here being, we all do things our own way.

It’s fair to contend unpunctuality is bad for economic growth and that schedules are vital to maintaining efficiency.

But when we look at the fact Americans work extensive hours yet exhibit low levels of productivity, this argument feels somewhat empty and void.

As both societies and individuals, we all need to find the healthy balance between punctuality and lateness. Schedules are important, but breaking them isn’t the end of the world.

People with a tendency for tardiness like to stop and smell the roses, and those with a propensity for punctuality could learn a thing or two from them (and vice versa).

Life was never meant to be planned down to the last detail. Remaining excessively attached to timetables signifies an inability to enjoy the moment.

Living in the present is vital to our sanity. Sometimes it’s much more beneficial to go with the flow.

We can’t spend all of our time dwelling on the past or dreaming of the future, or we end up missing out on the wonderful things occurring around us.

http://elitedaily.com/life/culture/optimistic-people-have-one-thing-common-always-late/1097735/

By Gregory Walton

Radical new research led by a British scientist has suggested that there may be a second universe where time runs backwards.

The theoretical claims put forward in the Physical Review Letters journal could revolutionise the field of research into the origin and future of the universe.

In the paper titled ‘Identification of a Gravitational Arrow of Time’, an international team of world renowned scientists led by Oxfordshire-based Dr Julian Barbour challenge assumptions about the so called ‘arrow of time’.

The ‘arrow of time’ is the theory that time is symmetric and therefore time moves forward. They contend that there is no scientific reason that a mirror universe could not have been created where time moved in an distinct way from our own.

But in a quirk of science it is thought that if a parallel universe did exist where time moved backward, any sentient beings there would consider that time in our universe in fact moved backward.

The arrow of time is also known as the ‘one-way’ direction of time and was devised by a British scientist, Dr Arthur Eddington, in the twenties.

All of the laws of physics apply no matter which way time is moving and therefore there is no scientific impediment to such a parallel universe.

Dr. Barbour says: “Time is a mystery. Basically, all the known laws of physics look exactly the same whichever way time runs, and in the world in which we live in everything goes in one direction.”

“If you look at a simple model with a swarm of bees in the middle of the Big Bang but breaking up in either direction, then you would say there are two arrows of time, pointing in opposite direction from the swarm. One arrow would be forwards and one backwards.”

However Dr Barbour acknowledges that locating the ‘other’ universe in practical terms is an altogether different question.

“Our results are a proof of principle,” he said.

http://www.telegraph.co.uk/news/science/science-news/11285605/Did-the-Big-Bang-create-a-parallel-universe-where-time-goes-backwards.html