A Very Clever Experimental Test of a Bell Inequality

Posted in The Universe and Stuff with tags , , on August 26, 2015 by telescoper

Travelling and very busy most of today so not much time to post. I did, however, however get time to peruse a very nice paper I saw on the arXiv with the following abstract:

For more than 80 years, the counterintuitive predictions of quantum theory have stimulated debate about the nature of reality. In his seminal work, John Bell proved that no theory of nature that obeys locality and realism can reproduce all the predictions of quantum theory. Bell showed that in any local realist theory the correlations between distant measurements satisfy an inequality and, moreover, that this inequality can be violated according to quantum theory. This provided a recipe for experimental tests of the fundamental principles underlying the laws of nature. In the past decades, numerous ingenious Bell inequality tests have been reported. However, because of experimental limitations, all experiments to date required additional assumptions to obtain a contradiction with local realism, resulting in loopholes. Here we report on a Bell experiment that is free of any such additional assumption and thus directly tests the principles underlying Bell’s inequality. We employ an event-ready scheme that enables the generation of high-fidelity entanglement between distant electron spins. Efficient spin readout avoids the fair sampling assumption (detection loophole), while the use of fast random basis selection and readout combined with a spatial separation of 1.3 km ensure the required locality conditions. We perform 245 trials testing the CHSH-Bell inequality S≤2 and find S=2.42±0.20. A null hypothesis test yields a probability of p=0.039 that a local-realist model for space-like separated sites produces data with a violation at least as large as observed, even when allowing for memory in the devices. This result rules out large classes of local realist theories, and paves the way for implementing device-independent quantum-secure communication and randomness certification.

While there’s nothing particularly surprising about the result – the nonlocality of quantum physics is pretty well established – this is a particularly neat experiment so I encourage you to read the paper!

Perhaps some day someone will carry out this, even neater, experiment!

PS Anyone know where I can apply to for a randomness certificate?

When scientists help to sell pseudoscience: The many worlds of woo

Posted in The Universe and Stuff on August 25, 2015 by telescoper

telescoper:

Since Professor Moriarty has mentioned me by name (not once, but twice) in his latest post, the least I can do is reblog it. In fact I agree wholeheartedly with his demolition of the pathological industry that has grown up around “Quantum Woo”…

Originally posted on Symptoms Of The Universe:

…or, as Peter Coles suggested, The Empirical Strikes Back


Until a couple of weeks ago, I was blissfully unaware that there was a secret out there that had the potential to change my life forever. I could do anything, be anything, get anything I so desired… if I only knew The Secret. Despite my hitherto abject ignorance, it’s not a particularly well-kept secret: millions know about it — and its universal law of attraction guiding ‘principle’ — largely due to Oprah Winfrey’s glowing and gushing endorsement:

Nor is The Secret anything new. The film which first gave it away was released nearly a decade ago. Like the best memes, however, its rate of infection continues to grow. Googling “The Law of Attraction” gives millions upon millions of hits, and counting.

I found out about The Secret via Tim Brownson and Olivier Larvor, both mentioned in my previous post…

View original 2,947 more words

Early Autumn?

Posted in Brighton with tags , , , on August 24, 2015 by telescoper

This seems a bit strange. I was on campus yesterday (23rd August) and noticed that the leaves are already falling from the trees:

Early Autmn

Has Autumn come early to Sussex this year? Or is this normal? Anyone noticed anything like this elsewhere?

A Tribute to Richard Attenborough

Posted in Film with tags , , on August 24, 2015 by telescoper

It’s a year to the day since Richard Attenborough passed away, so the University of Sussex (of which he was Chancellor for many years) paid tribute to his life and work in memorable style at the weekend, against the backdrop of the newly-refurbished Attenborough Centre for the Creative Arts, which will be officially opened next week.

The Last Match

Posted in Cricket, History with tags , , , , , on August 23, 2015 by telescoper

Yesterday (Saturday 22nd August) I took the day off to go to Sussex County Cricket Club‘s ground at Hove watch some cricket and also to watch a play called The Last Match. Here’s a snap I took in the direction of the scoreboard as play commenced, at 11am.

Hove_cricket

As you can see from the picture, it was very sunny yesterday – the high cloud had vanished by the afternoon to leave a perfectly cloudless blue sky. I arrived at the ground already rather hot, having walked from Kemptown (which lies well to the East of Hove) along the seafront and through Brighton city centre to get there. Fortunately, cricket grounds are not short of options for liquid refreshment!

The match going on was between Sussex and Yorkshire in the County Championship. I haven’t seen much County cricket in recent years, but it was good to see a reasonably big crowd there. Many of them were Yorkshire supporters who had presumably made the short trip South from the Midlands to watch the game. Saturday was the second day of a four-day game. Yorkshire had batted first on day 1 and reached 346-6 by close of play, with Gary Ballance not out on 98 and Tim Bresnan not out on 44 (both former England players). No sooner had I settled into my seat than Ballance got his century, but Bresnan took about 35 minutes to get to his fifty. Thereafter the Yorkshire batsman progressed steadily, adding a hundred to their overnight score without losing a wicket but soon after that Ballance was out for 165, clean bowled by Liddle. A few runs later Bresnan was run out in controversial fashion: the batsmen went for a quick single, fielder Chris Nash threw at the bowler’s end whereupon the bowler caught it and fell on the stumps, knocking them all over with Bresnan short of his ground. The umpire’s finger went up, but it should have been not out, because the ball is supposed to hit the stumps at some point. Anyway, the umpire’s decision is final – no reviews in County cricket – so Bresnan was out for 78 with the score on 458-8. Had I been Yorkshire captain I would probably have declared then to let my bowlers have a go at Sussex before lunch. But that didn’t happen.

Six overs later the ninth wicket fell, at about 12.59 (with lunch scheduled for 1pm). Then a rule was invoked with which I was unfamiliar. Apparently in County cricket if a wicket falls just before lunch, so that the batting side is nine down, play continues for up to 30 minutes (or 8 overs) or until the final wicket falls. Thus it came to pass that, possibly for the first time ever in the history of cricket, play stopped Play…

The Play concerned was due to start at 1.15 in one of the function rooms at the boundary of the ground, but the organizers decided to hold back the start until the session of play (in the cricketing sense) had actually finished. As it happened, the last wicket pair for Yorkshire batted about 7 overs and added 35 runs until Plunkett was run out. Yorkshire’s innings closed at 494 all out. Now the Play could start.

The subject of The Last Match was legendary Yorkshire spin bowler Hedley Verity. I posted about him not long ago so I won’t repeat his life story here, but the point was that the last match he ever played in for Yorkshire (and indeed the last competitive match he ever played in) was the County Championship fixture against Sussex at Hove which took place from August 30th to September 1st 1939. Hence the poem I posted yesterday, which is actually quoted during the play.

The significance of the date September 1st 1939 is that was when German forces began the invasion of Poland, which commenced at 5am UK time. Although Britain did not formally declare war on Germany until 3rd September, the invasion of Poland did lead to various emergency measures being immediately adopted in Britain. One of these was that a plan to evacuate all children of school age from major cities was implemented on that day. On the morning of 1st September the Yorkshire players were told that they should abandon the final day and return home. Verity must have been especially keen to rejoin his family, as he had two young children to think about. Yorkshire had by then already won the County Championship so there wasn’t really that much to play for. However, the players on both sides discussed what to do and decided to play out the match, the main reason being that it was a benefit match for Jim Parks. I’d also suggest that the players probably knew they wouldn’t be playing cricket again for a long time, and wanted to savour the last monents of peaceful normality, much as a condemned man might savour his last cigarette.

It’s probable that the cricketers’ minds were not entirely on the match that day, but what happened was remarkable nevertheless. Sussex had batted first and score 387 all out; Yorkshire managed 392 all out in their first innings. Verity had taken only 2 for 108 off 18 overs in the first innings, which makes the second innings all the more remarkable. Sussex were bowled out for a paltry 33, with Verity the destroyer (6-1-9-7). Yorkshire then knocked off the 30 required to win for the loss of one wicket, and won the match. The Yorkshire players bundled onto their coach and travelled home.

Verity subsequently enlisted in the British Army and, as a Captain in the Green Howards, took part in the invasion of Sicily in 1943. During the Battle for Catania, Verity was ordered to lead his unit in a night attack on a farmhouse occupied by German soldiers. He did so, but he had walked into a trap and they were quickly surrounded. Half his men were killed and he received a bullet in the chest. He died of his wounds in a prisoner of war camp at Caserta, near Naples on July 31st 1943, at the age of 38, but the official telegram informing his family that he had been killed was not sent until some time later; it was dated 1st September 1943..

Apart a brief preamble and some film footage projected at the rear of the stage, most of The Last Match is set in the hospital in which Verity spent his last days and revolves around a conversation between himself (played by Al Barclay) and a fictional character, Francis Watson (played by Daniel Abelson) whose role is to hold a mirror up to Verity. Francis is younger, more cynical and from a wealthier background than Verity who comes across as rather old-fashioned but with a strong sense of personal duty. It only lasts about 35 minutes, but in that short time it touches on a wide range of issues, especially the conflict between freedom and responsibility. It’s a poignant story, well written and acted, although its brevity means that there’s no time to develop the characters fully. It did occur to me watching it that it would work very well as a radio play, and I hear that there has been some discussion of that possibility.

Congratulations to writers Colin Philpott and Kit Monkman for such a thought-provoking piece. It certainly added an interestingly different dimension to a day’s cricket. The production now moves to Yorkshire – it will be at Yorkshire County Cricket Ground, Headingly on 1st September and again on 24th September, and a couple of other venues in between. Do go and see it if you get a chance.

So then it was back to the cricket, sunshine and (I must admit) some beers – Harvey’s mainly! On what seemed to be a good batting wicket, the Sussex batsmen struggled early on against an impressive Yorkshire pace attack (Sidebottom, Bresnan, Plunkett and Patterson; the first three of whom are former England bowlers). Despite numerous appeals, a lot of playing and missing, and more oohs and aahs than you will hear in a Frankie Howerd monologue, openers Ed Joyce and Luke Wells put on 110 for the first wicket before Wells fell to Adil Rashid for 43. A couple of balls later Rashid also dismissed the hapless Machan for a duck. Plunkett trapped Nash lbw for 18 to make it 139-3. Ed Joyce brought up his century with a six off Rashid, and almost immediately departed off the same bowler to make it 175-4, whereupon Sussex sent on a nightwatchman, Oliver Robinson, who was almost out first ball to Rashid but clung on until close of play.

Honours pretty even I’d say at the end of day 2, and this (Sunday) morning’s session having been lost to rain with more bad weather forecast for tomorrow, I suspect this one will be a draw.

So there you have it. War and peace. Life and death. Sussex and Yorkshire. Beer and lovely weather. What more could you want from a day off?

UPDATE: Monday 24th August. Sussex ended day 3 on 493-7 with centuries for Michael Yardy and Ben Brown. No play was possible this morning, the final day, because of heavy rain, so the match does indeed look set to be a draw.

UPDATE to the UPDATE: No play was possible on Monday at all due to rain, so the game did indeed end as a draw.

September 1st, 1939

Posted in Poetry with tags , , on August 22, 2015 by telescoper

I have been out all day at an event that commemorates something that happened on September 1st 1939. No time to write about it tonight, but until I do it seems apt to post this poem By W.H. auden..

I sit in one of the dives
On Fifty-second Street
Uncertain and afraid
As the clever hopes expire
Of a low dishonest decade:
Waves of anger and fear
Circulate over the bright
And darkened lands of the earth,
Obsessing our private lives;
The unmentionable odour of death
Offends the September night.

Accurate scholarship can
Unearth the whole offence
From Luther until now
That has driven a culture mad,
Find what occurred at Linz,
What huge imago made
A psychopathic god:
I and the public know
What all schoolchildren learn,
Those to whom evil is done
Do evil in return.

Exiled Thucydides knew
All that a speech can say
About Democracy,
And what dictators do,
The elderly rubbish they talk
To an apathetic grave;
Analysed all in his book,
The enlightenment driven away,
The habit-forming pain,
Mismanagement and grief:
We must suffer them all again.

Into this neutral air
Where blind skyscrapers use
Their full height to proclaim
The strength of Collective Man,
Each language pours its vain
Competitive excuse:
But who can live for long
In an euphoric dream;
Out of the mirror they stare,
Imperialism’s face
And the international wrong.

Faces along the bar
Cling to their average day:
The lights must never go out,
The music must always play,
All the conventions conspire
To make this fort assume
The furniture of home;
Lest we should see where we are,
Lost in a haunted wood,
Children afraid of the night
Who have never been happy or good.

The windiest militant trash
Important Persons shout
Is not so crude as our wish:
What mad Nijinsky wrote
About Diaghilev
Is true of the normal heart;
For the error bred in the bone
Of each woman and each man
Craves what it cannot have,
Not universal love
But to be loved alone.

From the conservative dark
Into the ethical life
The dense commuters come,
Repeating their morning vow;
‘I will be true to the wife,
I’ll concentrate more on my work,’
And helpless governors wake
To resume their compulsory game:
Who can release them now,
Who can reach the dead,
Who can speak for the dumb?

All I have is a voice
To undo the folded lie,
The romantic lie in the brain
Of the sensual man-in-the-street
And the lie of Authority
Whose buildings grope the sky:
There is no such thing as the State
And no one exists alone;
Hunger allows no choice
To the citizen or the police;
We must love one another or die.

Defenseless under the night
Our world in stupor lies;
Yet, dotted everywhere,
Ironic points of light
Flash out wherever the Just
Exchange their messages:
May I, composed like them
Of Eros and of dust,
Beleaguered by the same
Negation and despair,
Show an affirming flame.

Original Jelly Roll Blues

Posted in Jazz with tags , , on August 21, 2015 by telescoper

Well, it’s a sunny Friday afternoon here so I thought I’d wind down for the weekend by posting a nice bit of Jazz to end the week. This is a version of a famous composition (by Jelly Roll Morton) made by Humphrey Lyttelton with his Paseo Jazz Band. This consisted of the core of Humph’s band of the time – notably Humph himself on trumpet and Wally Fawkes on clarinet – with the addition of a large number of West Indian musicians whom Humph had met in London; the recordings they made together are an absolute blast, largely because of the fusion of traditional jazz with Caribbean rhythms. The sound contrasts with a lot of the “trad” jazz at the time, but is if anything more authentic than that of many revivalist bands of the period because it echoes the astonishing blend of cultures that was characteristic of New Orleans at the time Jazz was born. This tune in particular gets a rhythmic backdrop of congas, bongos, claves and maracas that gives it a lovely lilting feel. And on top of all the extra percussion there is Fitzroy Coleman’s guitar which was then, is now, and forever shall be, a joy. It’s a very original version indeed of the Original Jelly Roll Blues…

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