La dematerializzazione della fisica: l'Universo è un gigantesco computer quantistico
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La dematerializzazione della fisica:
l’Universo è un gigantesco computer quantistico
Giacomo Mauro D’Ariano
Università di Pavia
Giacomo Mauro D’Ariano
Seralmente, Università degli Studi di Torino
Stephen Wolfram
Konrad Zuse
John Archibald Wheeler
Gerard ’t Hooft
Carl Friedrich von Weizsäcker
Cambio di paradigma Meccanico Informatico “oggetto” “sistema”
Due grandi teorie
Teoria Quantistica dei Campi
Relatività Generale
Occorre una teoria più
fondamentale che unifichi le due
teorie
Cosa dobbiamo capire:
La realtà:
‣ non è così come ci appare
‣ è quantistica
‣ è un immenso computer quantistico
‣ la risoluzione è altissima
Cosa dobbiamo capire:
La realtà:
‣ non è così come ci appare
‣ è quantistica
‣ è un immenso computer quantistico
‣ la risoluzione è altissimaSappiamo che tutto il mondo fisico deve
obbedire alla teoria quantistica
La teoria quantistica è la grammatica della fisicaL’esperimento della doppia fenditura
L’esperimento della doppia fenditura Fred Alan Wolf Dott. Quantum
L’esperimento della doppia fenditura Fred Alan Wolf Dott. Quantum
Dualismo onda-corpuscolo
vale per ogni tipo di particella:
materiale, luce, …L’esperimento della doppia fenditura
La meccanica quantistica è alla base della tecnologia attuale
Il computer Mark-I
Il transistor
Intel 4004
Pentium Intel
Applicazioni della meccanica quantistica editorial
Quantum possibilities
Commercial quantum devices are in their infancy, but the growing industry targeting quantum technologies is
already having a tangible effect on the job market.
A
t the March meeting of the American that there are plenty of job opportunities “For the students, even the exposure to
Physical Society in Los Angeles this for quantum physicists eager to start their the questions posed by these engineering
year, the Google Quantum AI lab careers beyond academia. challenges makes a big difference.”
presented Bristlecone, their newest quantum The symbiosis between academia and The first cohort of Bristol-trained
processor and the latest development on high-tech companies has been a reality in quantum engineers started their doctoral
the road towards a quantum computer1. many fields of physics for decades — a well- course in 2014, and several similar
The machine boasts 72 qubits, but it’s known example being the semiconductor programmes have been set up around the
possible that many young physicists at the industry. Nonetheless, just a few years ago same time elsewhere in the UK. Of course, the
meeting were more interested in the fact it would have been difficult to imagine opportunities to obtain training that is well-
that Google was also throwing a so-called a flourishing job market or widespread suited to research in the world of quantum
quantum AI party. With IBM and Rigetti commercial prospects to be strong points technologies don’t stop at bespoke PhD
Computing hosting similar events, it would in favour of starting a PhD in quantum programs or in the UK: aspiring quantum
seem that now is a good time to be working information. Perhaps slightly more unusual technologists can already choose between a
on quantum computing. is this sector’s thirst for theorists: the quantum computing professional certificate
These companies belong to a Quantum Information Processing (QIP) from MIT, a Master in Science at QuTech
burgeoning industry looking to develop conference, an event traditionally focused on Academy Delft or a junior quantum engineer
and commercialize quantum technologies. theoretical work, hosted an industry session program hosted by Rigetti computing. No
No matter how different the physics of a this year, with career opportunities in doubt many other courses will follow.
quantum device may be with respect to its prominent display. The promise of quantum Although there are plenty of reasons
classical analogues, the business landscape advantage for solving optimization problems to celebrate these working and learning
that is taking shape around this technology and the need to develop native quantum possibilities, as often happens in the presence
looks fairly standard in its makeup. The programming languages for future quantum of large-scale changes driven by massive
dominating forces seem to be the quantum computers, however, explains it all. investments, eyebrows have also been raised.
research arms of well-established computing Proficiency in quantum mechanics is It’s not uncommon to encounter, half-
e molto
companies, surrounded by an ecosystem an unavoidable requirement for those who whispered at conferences, that inevitable
of start-ups and university spin-offs. These wish to develop the quantum technology scepticism born out of the concern that
join companies such as ID Quantique and of tomorrow. However, the fast-paced sizable commercial interests may somehow
D-Wave, pioneers from a previous wave environment of a research field on the compromise the purity of the fundamental
of investment in quantum technologies2 verge of a technological turning point scientific endeavour. Moreover, there is also
altro
around the year 2000. poses challenges that the average quantum the danger that the industry’s potential better
There is something for all tastes: from the physicists may not be trained to tackle — remuneration and career opportunities
manufacturers of quantum computers on a even to make progress within academic may start to systematically siphon the most
variety of platforms (the ones that regularly research. Since Stephanie Wehner, professor brilliant students away from academic
make the headlines) to developers of quantum of quantum information in Delft, and quantum research. After all, choosing
sensors or cryptographic devices. But
there are also companies creating quantum
algorithms, with varying degrees of classical
hybridization and machine-learning thrown
into the mix. And there are also consultants
her team set about developing a quantum
internet, they are faced with problems that
traditionally fall in the remit of computer
science. These included, for example, the
development of packet-routing protocols:
industry over academia no longer requires a
step away from the quantum world.
Regardless of how one feels about the
rapid expansion of this industry, it’s fair
to say that the mixture of excitement and
ancora …
tasked with addressing difficult problems by a task that has little to do with quantum investment in the quantum technologies
dipping into the quantum world as the need physics itself, but requires that one takes industry seems to be all to the students’
arises, perhaps with the help of a quantum into account the quantum nature of the advantage. Graduates now have access to
annealer. These are complemented by an array underlying information carriers. a growing quantum-focused job market
of intermediaries seeking to help existing The need for professionals with a more that provides concrete alternatives to an
companies understand how they could benefit varied skillset that includes, but is not academic career — a possibility that was not
from the looming quantum revolution — or
avoid being caught off-guard by it. To get
limited to, quantum physics, has led to the
creation of tailored degrees. “Industries
editorial
always available to their older colleagues. ❐
a feeling of the diversity of companies want people with this ability to function
Quantum possibilities
involved in this endeavour, the program of effectively in an interdisciplinary team, Published online: 6 April 2018
the Quantum Computing for Business because not everyone is going to have https://doi.org/10.1038/s41567-018-0125-9
conference provides a good example3. the same training or background when
What form
Commercial a commercial
quantum devicesquantum working in
are in their infancy, butquantum tech. Weindustry
the growing think thattargeting quantum technologies is
References
revolution might take, or indeed whether this has benefits for the research field as 1. Kelly, J. A Preview of Bristlecone, Google’s new quantum
already having
there will a tangible
be one effect
at all, is the sort ofon the job market.
question well,” explains Peter Turner, director of the processor. Google Research Blog (5 March 2018); http://go.nature.
com/2IKWLIo
investors bet on. But the rapid expansion of Quantum Engineering Centre for DoctoralCosa dobbiamo capire:
La realtà:
‣ non è così come ci appare
‣ è quantistica
‣ è un immenso computer quantistico
‣ la risoluzione è altissimaIl quantum computer
Un quantum computer utilizza “qubits”: quantum bits.
Un quantum bit può assumere i valori 0 e 1, ma può anche assumere
i due valori “contemporaneamente”, (in sovrapposizione)!Fattorizzazione in primi
Algoritmo per fattorizzare in primi: complessità
esponenziale!
Esempio: nel 1994 ci sono voluti 8 mesi di
calcolo parallelo di 1600 workstations per
fattorizzare un numero di 129 cifre.
Con la stessa potenza di calcolo ci vorrebbero
800,000 anni per un numero di 250 cifre
e 10^25 anni per un numero di 1000 cifre!!!!Fattorizzazione in primi
Se avessimo un quantum computer potremmo usare
l’algoritmo di Shor, che ha complessità polinomiale.
Per un numero di 1000 cifre basterebbero
pochi milioni di steps!!!Una nuova informatica: l’Informatica quantistica
QUANTUM TOMOGRAPHY
QUANTUM TELEPORTATIONLa lezione della teoria quantistica
Non località dovuta all’entanglement:
il risultato della misurazione è inerentemente probabilistico,
ovvero non può essere interpretato come lettura di una realtà
pre-esistente locale.
Ci sono due alternative:
1.il risultato è generato all’atto della misurazione
oppure
2.il risultato dipende da operazioni eseguite remotamentea
School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel; bSchmid College of Science and Technology, Chapman University, Orange, CA
92866; cInstitute for Quantum Studies, Chapman University, Orange, CA 92866; dDipartimento di Matematica, Politecnico di Milano, 20133 Milan, Italy;
and eH. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
Contributed by Yakir Aharonov, November 12, 2015 (sent for review April 3, 2015; reviewed by Charles H. Bennett and Lucien Hardy)
The pigeonhole principle: “If you put three pigeons in two pigeon- To find those instances we subject each particle to a second
La lezione della teoria quantistica
holes, at least two of the pigeons end up in the same hole,” is an
obvious yet fundamental principle of nature as it captures the very
essence of counting. Here however we show that in quantum me-
chanics this is not true! We find instances when three quantum
particles are put in two boxes, yet no two particles are in the same
measurement:
pffiffiffi we measure whether each pffiffiffi particle is in the state
j+ ii = ð1= 2ÞðjLi + ijRiÞ or j− ii = ð1= 2ÞðjLi − ijRiÞ (these are
two orthogonal states, so there exists a hermitian operator
whose eigenstates they are––we measure that operator). The
cases we are interested in are those in which all particles are
box. Furthermore, we show that the above “quantum pigeonhole found in j + ii, i.e., the final state
principle” is only one of a host of related quantum effects, and
points to a very interesting structure of quantum mechanics that jΦi = j+ ii1 j+ ii2 j+ ii3 . [3]
was hitherto unnoticed. Our results shed new light on the very
notions of separability and correlations in quantum mechanics Importantly, neither the initial state nor the finally selected
and on the nature of interactions. It also presents a new role for state contains any correlations between the position of the
entanglement, complementary to the usual one. Finally, interfero- particles. Furthermore, both the preparation and the postse-
metric experiments that illustrate our effects are proposed.
Particolari stati “entangled”:
lection are done independently, acting on each particle
separately.
|
weak value and weak measurement entanglement and quantum
Let us now check whether two of the particles are in the same
| | |
nonlocality correlations two-state vector formalism foundations of
box. Because the state is symmetric, we could focus on particles 1
quantum mechanics
and 2 without any loss of generality; any result obtained for this
pair applies to every other pair.
Particles 1 and 2 being in the same box means the state being in
di tre particelle che possono solo stare in due scatole,
Quantum Pigeonhole Principle
Arguably the most important lesson of quantum mechanics is that
we need to critically revisit our most basic assumptions about
the subspace spanned by jLi1 jLi2 and jRi1 jRi2; being in different
boxes corresponds to the complementary subspace, spanned by
jLi1 jRi2 and jRi1 jLi2. The projectors corresponding to these
non ce ne sono mai due nella medesima scatola!
nature. It all started with challenging the idea that particles can subspaces are
have, at the same time, both a well-defined position and a well-
defined momentum, and went on and on to similar paradoxical
facts. But, the pigeonhole principle that is the subject of our paper Πsame LL
1,2 = Π1,2 + Π1,2
RR
RL , [4]
(Aharonov et al., Proc Natl Acad Sci USA, 113 532 2016.)
seems far less likely to be challenged. Indeed, although on one
hand it relates to physical properties of objects––it deals, say, with
Πdiff
1,2 = Π LR
1,2 + Π1,2
actual pigeons and pigeonholes––it also encapsulates abstract where
mathematical notions that go to the core of what numbers and
counting are so it underlies, implicitly or explicitly, virtually the Significance
whole of mathematics. [In its explicit form the principle was first
stated by Dirichlet in 1834 (1) and even in its simplest form its uses We show that quantum mechanics violates one of the funda-
in mathematics are numerous and highly nontrivial (2).] It seems mental principles of nature: If you put three particles in two
therefore to be an abstract and immutable truth, beyond any boxes, necessarily two particles will end up in the same box.
doubt. Yet, as we show here, for quantum particles the principle We find instances when three quantum particles are put in two
does not hold. boxes, yet no two particles are in the same box, a seemingly
Consider three particles and two boxes, denoted L (left) and R impossible and absurd effect. This is only one of a host of re-
(right). To start our experiment, we prepare each particle in a lated quantum effects which we discovered and which point to
superposition of being in the two boxes, a very interesting structure of quantum mechanics that was
hitherto unnoticed and has major implications for our un-
1 derstanding of nature. It requires us to revisit some of the most
j+i = pffiffiffi ðjLi + jRiÞ. [1]
2 basic notions of quantum physics––the notions of separability,
of correlations, and of interactions.
The overall state of the three particles is thereforep
Il concetto di particella
non è sostenibile
what is
Q U A N T U M P H YS I C S
Meinard Kuhlmann, a philosophy professor at Bielefeld
University in Germany, received dual degrees in physics and
in philosophy and has worked at the universities of Oxford,
Chicago and Pittsburgh. As a student, he had an inquisitive
reputation. “I would ask a lot of questions just for fun and
because they produced an entertaining confusion,” he says.
32 Scientific American, August 2013
Physicists routinely describe the universe as © 2013 Scientific American
being made of tiny subatomic particles that
push and pull on one another by means of
force fields. They call their subject “particle
physics” and their instruments “particle accel-
ican articles. However compelling it might appear, it is not at
erators.” They hew to a Lego-like model of the all satisfactory.
what is real?
world. But this view sweeps a little-known For starters, the two categories blur together. Quantum field
fact under the rug: the particle interpretation theory assigns a field to each type of elementary particle, so
there is an electron field as surely as there is an electron. At the
of quantum physics, as well as the field inter- same time, the force fields are quantized rather than continu-
pretation, stretches our conventional notions ous, which gives rise to particles such as the photon. So the dis-
of “particle” and “field” to such an extent that tinction between particles and fields appears to be artificial, and
physicists often speak as if one or the other is more fundamen-
ever more people think the world might be tal. Debate has swirled over this point—over whether quantum
made of something else entirely. field theory is ultimately about particles or about fields. It start-
ed as a battle of titans, with eminent physicists and philoso- Physicists speak of the world as being made of
particles and force fields, but it is not at all clear
The problem is not that physicists lack a valid theory of the phers on both sides. Even today both concepts are still in use for what particles and force fields actually are in the
quantum realm. The world may instead consist
subatomic realm. They do have one: it is called quantum field the- illustrative purposes, although most physicists would admit of bundles of properties, such as color and shape
ory. Theorists developed it between the late 1920s and early 1950s that the classical conceptions do not match what the theory By Meinard Kuhlmann
by merging the earlier theory of quantum mechanics with Ein- says. If the mental images conjured up by the words “particle” Photographs by Travis Rathbone
© 2013 Scientific American
August 2013, ScientificAmerican.com 33
stein’s special theory of relativity. Quantum field theory provides and “field” do not match what the theory says, physicists and
the conceptual underpinnings of the Standard Model of particle philosophers must figure out what to put in their place.
physics, which describes the fundamental building blocks of mat- With the two standard, classical options gridlocked, some phi-
ter and their interactions in one common framework. In terms of losophers of physics have been formulating more radical alterna-
empirical precision, it is the most successful theory in the history tives. They suggest that the most basic constituents of the materi-
of science. Physicists use it every day to calculate the aftermath of al world are intangible entities such as relations or properties.
particle collisions, the synthesis of matter in the big bang, the ex- One particularly radical idea is that everything can be reduced tonon-relativistic spacetimes (as well as for relativistic spacetimes); thoug
of course, we should not expect either causality condition to hold in th
Il problema della non-relativistic case.
Malament (1996)
localizzazione
Theorem 1 (Malament). Let (H,A H-> E&,a *-* U(a)) be a locali
tion system over Minkowski spacetime that satisfies:
(1) Localizability
(2) Translation covariance
(3) Energy bounded below
(4) Microcausality
Then EA = 0 for all A.la particella è uno “stato” del campo quantistico!
la particella è una regola di probabilità!
come un numero fra 1 e 6 lo è per un dado
o i valori 0 e 1 sono per il bit classico
Ma è un dado quantistico!La lezione della teoria quantistica Holismo: La conoscenza del tutto non implica la conoscenza delle parti. Esistono proprietà del tutto che sono incompatibili con qualunque proprietà delle parti.
La lezione della teoria quantistica
La nozione di oggetto come “insieme di proprietà” è
insostenibile.
Occorre sostituirla con quelle di sistema e di evento.
“oggetto” “sistema”Fondation Jean Piaget
Osserviamo eventi, non oggetti!
Chapitre)original)servant)d’introduction)au)recueil)d’articles)
Psychologie)et)épistémologie)publié)chez)
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Principi per la
teoria quantistica
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Cayley graph on Cayley graph
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m=0: deformed Lorentz
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Free Quantum
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m ∈ S1
LTM Standards discrete proper timeL’algoritmo della “particella relativistica” è l’algoritmo quantistico più semplice! La meccanica quantistica relativistica delle particelle discende da principi puramente informatici, senza usare: meccanica, cinematica, spazio-tempo, relatività, … In particolare, si ricava la relatività ristretta… Si ricava la fisica da matematica pura, senza usare primitive fisiche. La fisica emerge da un grande schermo digitale quantistico!
Version April 24, 2018 submitted to Entropy 12 of 16
La teoria che si ricava è
un automa cellulare quantistico
Figure 5. We show the evolution of a bound state of the two particles peaked around the value of the
total momentum p = 0.035p. The mass paramater is m = 0.6 and the coupling constant c = 0.2p. On
nel caso della teoria
the left is depicted the probability distribution of the initial state and on the right the that of the evolved
state after t = 128 time-steps. One can notice that in the relative coordinate x1 x2 the probability
delle particelle non
distribution remains concentrated on the diagonal, highlighting that the two particles are in a bound
state. The diffusion of the state happens only in the centre of mass coordinate.
interagenti è un
quantum walkD’Ariano, Mosco, Perinotti, Tosini, Entropy 2016 18 228
Dirac 3d
mass: 0.002
sigma: 32
x0: [140,140,140]
k0: [0.05,0.05,0.05]
spinor: ["Exp[I k0.#]",0,0,0]BGMP
Yi , A j , Bk , Dm Cl , En , F p , Gq
BGMP A B e
Dm
A
EA
Fenomenologia nuova
Cl , En , F p , Gq A j
B e
F B e e E
Aj
F e
p(A j , Yi ) = Yi A j p(A j , Y , i) = Y ,
HE e F e i H
A
p(A jA
B
, Yi ) = Yi O e , e
j H ee
E F e O e
= Yi O, e
H e ——————
1. tutto è Fermionico GR + QFT: la scala di Planck
O e
—————— ——————
2. “raddoppiano” le specie di particelle
Due particelle che collidono all’energia di Planck
—————— 2p 2p (.54MWh) producono un buco nero!
kx k⇤ 3.
) afrequenza
⇤= w w⇤ ) t⇤ = ,
, massima m m⇤
k⇤ w⇤
2p 2p 2p Una particella con una massa 2ptroppo grande
x k⇤ ) a =
4. vettore , w w ) t
kx k⇤ ) a⇤w= = , m mw -5g)wdiventa
⇤ ) tun mm
k⇤ d’onda massimo , (2.18*10 ⇤= ,
⇤ ⇤ ⇤ ⇤
1 h̄k ⇤ k⇤ w⇤
buco nero!
m⇤ = lim 2pp
w 5. wmassa
⇤ ) tdi⇤= particella m c(0)
k!0 , 3pmassima
c(k) m⇤
w⇤ 1 h̄k Planck mass
m⇤ = lim p a ⇤ 1 h̄k
c := c(0)k!0
6. dispersione del vuoto
= h̄ = mc(0)
,3p c(k) ⇤ a⇤ c m⇤ = lim p
c⇤ k!0 3p c(k) c(0)
1 h̄k a⇤
= lim 7. …
p c := c(0) = , h̄ = m⇤ a⇤ c
k!0 3p c(k) c(0) c⇤ a⇤
c := c(0) = , h̄ = m⇤ a⇤ c
a⇤ c⇤
0) = , h̄ = m⇤ a⇤ c
c⇤Cosa dobbiamo capire:
La realtà:
‣ non è così come ci appare
‣ è quantistica
‣ è un immenso computer quantistico
‣ la risoluzione è altissimaAj
e ——————
E F e
p(A j , Yi ) = Yi
H——————
e
, ——————
Teoria puramente matematica contiene i suoi standards LTM
e O
2p —————— 2p 2p
kx k⇤ 2p
) a⇤ = , kw k⇤ w
x = t⇤ , = w , w⇤ ) t⇤m
)⇤a⇤) =
2p
k m m⇤w⇤
k⇤
kx k⇤ ) a⇤ = , w ⇤ w⇤ ) t⇤ = ,
2p
k⇤ 2p
w⇤
kx k⇤ ) a⇤ = , w w⇤ ) t⇤ = , m m⇤ 1 h̄k
k⇤ w⇤ m⇤ = lim p
Utilizzando l’argomento
1 h̄k 1 h̄k k!0 3p c(k) c(
del mini buco nero si ha1
m lim m⇤ = lim p
h̄kp a⇤
}
=
m⇤ = lim⇤p
m∗ : massa di Planck 3p c(k)
c(k) c(0)
k!0 3p k!0 k!0c(0)3p c(k)c := c(0)
c(0)= ,
t⇤
h̄ = m
a⇤
h̄ =am⇤⇤ a⇤ c
c := c(0) = ,
t⇤
c := c(0) = , h̄ = ma ⇤⇤ a⇤ c
c44 :=
c c(0) = , h̄ = m⇤ a⇤ c
a⇤ = 1.62 ⇤ 10 35
m, t⇤ = 5.39 ⇤ 10 s, ⇤ m⇤ = 2.18 ⇤ 10 c8⇤
kg
dal limite
“relativistico”electron
The Planck scale
1cm3 —> 2.35*1098 = 1 tera di tera di .. di tera (8 volte) di qBp(A j , Yi ) = Yi
H
——————
,
e
BGMP O
——————
e ——————
A j , Bk , Dm Cl , En , F p , Gq
Teoria puramente matematica contiene i suoi standards LTM
——————
2p 2p 2p
kw k⇤ w
A B
kx kA⇤ 2p) a ⇤
e= , x
2p = t⇤ , = w , w⇤ ) t⇤m
)⇤a⇤) =
k m m⇤w⇤
j k
kx k⇤ )2p a⇤ =
E , e w 2pw⇤ ) t⇤ =
F ⇤ , ⇤
A jk,xYi )k⇤=)Y
a⇤i = H , kw⇤ w⇤ ) t⇤ =, , m m⇤ w⇤
k⇤ e w⇤ 1 h̄k
m⇤ = lim p
Utilizzando l’argomento
O e
1 h̄k 1 h̄k 1 h̄k k!0 3p c(k) c(
del mini bucom⇤nero si p
m
= lim ha
lim m = lim p a⇤
}
= p ⇤
m∗ : massa di Planck ⇤
k!0 3p c(k) c(0)
k!0 3p c(k) k!0c(0) 3p c(k)c := c(0)
c(0)= ,
t⇤
h̄ = m
—————— a⇤
c := c(0) = , h̄ =am⇤ a⇤ c
t⇤
c := c(0) =
⇤
, h̄ = a
m ⇤⇤ a⇤ c
c :=
c c(0) = , h̄ = m⇤ a⇤ c
a⇤ = 1.6210 35 m, t⇤ = 5.3910 44 s, ⇤ a⇤ = 2.1810 8ckg⇤
2p 2p
a⇤ = , w w⇤ ) t⇤ = , m m⇤
k⇤ w⇤
In principio m∗ si può misurare!
1 h̄k dal limite
m⇤ = lim p “relativistico”
k!0 3p c(k) c(0)
aARTICLES
PUBLISHED: 5 JUNE 2017 | VOLUME: 1 | ARTICLE NUMBER: 0139
In vacuo dispersion features for gamma-ray-burst
neutrinos and photons
ARTICLES
Giovanni Amelino-Camelia1,2*, Giacomo D’Amico1,2, Giacomo Rosati3 and Niccoló Loret4 NATURE ASTRONOMY
Over the past 15 years there has been considerable interest in the possibilityThe main challenges for the ininterpretation
of quantum-gravity-induced of the photon fea-
vacuo dispersion,
105
the possibility that spacetime itself might behave essentially like a dispersive
ture inmedium
terms offorthe
particle
modelpropagation.
(5) come from Twoprevious
recent data analyses
studies have exposed what might be in vacuo dispersion features for gamma-ray-burst (GRB) neutrinos of energy in
based on equation (5), which had given negative the rangeresults35–37. Most
of 100 TeV and for GRB photons with energy in the range of 10 GeV. We of here show
these that these
previous two features
analyses are roughly
focused mainly com- photons associ-
on single
4
patible 10
with a description such that the same effects apply over four orders
ated toofamagnitude in energy.results
GRB, and produced We alsothatshow thattoitbe incompatible
appear
should not happen so frequently that such pronounced features arise accidentally, as a result of (still unknown) aspects of the
with values of η of about 30 (as considered in the present study).
mechanisms producing photons at GRBs or as a result of background neutrinos accidentallyγ fitting the profile of a GRB neutrino
affected by in vacuo dispersion.
1,000
This might suggest that the correct (‘fundamental’) description
of the effects considered here is of a statistical nature, such that it
|∆t|/(1 + z) (s)
might be unnoticeable in certain analyses focused on a single par-
T
possibility of quantum-gravity-induced in vacuo disper- Model ticle. Still, we feel that the 30 GeV photon observed from the short
he100
sion, an energy dependence of the travel times of ultrarelati- The class of scenarios wedeserves
GRB090510 intend tospecial
contemplate here is grounded
consideration, even ifinthe fundamental
vistic (that is, of negligible mass) particles from a given source some much-studied descriptionmodels
of theofeffects
spacetime quantization
is statistical
1–8
and, for
in nature. the 30 GeV photon
That
to a given detector, has been suggested in several studies . Part of type of data
1–10
wasanalyses we are
observed 35 interested in, has the implication that
within the half-second time window where most
10
the interest in this possibility comes from the fact that it is a rare the time needed for a ultrarelativistic particle to travel from a given
GRB090510 photons with energy between 1 and 10 GeV were also
example of a candidate quantum-gravity effect that could lead to source to a given detector receives a quantum spacetime correction,
observably large manifestations—even if, as it appears to be safe to here denoted observed.
as Δt. WeInfocus
lightonofthethis,
classitofisscenarios
naturalwhose
to assume
predic-that the 30GeV
assume, its1 characteristic length scale is of the order of the minute tions for energy photon(E)could not have
dependence of accrued
Δt can allan beindescribed
vacuo dispersion
in terms effect of more
Planck length (inverse of the Planck energy scale MP ≃ 1028 eV) or, of the following than half a second,
equation travelling
(working in unitsfrom a redshift
with the of 0.9 (the redshift of
speed-of-light
at the most, not much larger than that. scale c setGRB090510),
to 1): which implies |ηγ| < 1. It might be significant that the
The best opportunity
10 for
100such experimental
1,000 tests 10
has4 so far
105 30 GeV photon from GRB090510 is the only photon in our sample
been provided by observations of gamma-ray bursts (GRBs) , 1–4 E E
E*/(1 + z) (GeV)
comingΔtfrom
= ηX a short
D(z ) ±GRB:
δX if(zthe
D ) effect is present (1 ) for long GRBs
which set up a sort of race among photons of different ener- M M
and absent for short GRBs, then the interpretation should be astro-
P P
gies and (probably) neutrinos11–14, all emitted within a relatively physical. Alternatively, it could be noted that GRB090510, with its
Figuretime
small 3 | |Δt|/(1
window.+ z) The
versus E*/(1
fact + z)
that for understanding
our our GRB photonsofand theGRB Here the redshift (z) dependent D(z) carries information
neutrino candidates.
mechanisms producing Here the content
GRBs remainsof Figs 1 and 2 is
primitive hasthe
been combined
main
redshift of 0.9, is one of the closest GRBs relevant for our photon
on the distance between source and detector, and it factors in
challenge,
to allow ansince any ofgiven
overview time-of-arrival
the correlation between |Δt|/(1 + z)
difference between
and E*/(1 the analysis.
+ z).interplay A scenario
between quantuminspacetime
which theeffectseffect and
is pronounced
the cur- only at large
two particles can, in principle, always be attributed to the emis- vature of redshifts spacetime.could be of quantum
As usually done in the spacetime
relevant origin, but
literature 1–3of course would
sion mechanism. (keeping require
in mind athat
quantum spacetime
the possibility picture indescriptions,
of alternative which the dependence on
20Conclusioni la lezione della teoria quantistica, la logica, la matematica ci insegnano che la realtà: non è fatta di particelle, ma di informazione pura. È un immenso computer grafico quantistico con risoluzione altissima ed enorme potenza di calcolo
Projects: A Quantum-Digital Universe, Grant ID: 43796
Quantum Causal Structures, Grant ID: 60609
G. Chiribella, G. M. D'Ariano, P. Perinotti, Informational derivation of Quantum
Theory, Phys. Rev A 84 012311 (2011)
AND PERINOTTI
CHIRIBELLA
D’ARIANO,
.” s
or y ki
the oo ,’
is b up .
n tum n , th ound lates es! ”
ua o
dq uti e gr stu rcis
trib th c po exe
G. M. D'Ariano, P. Perinotti, The Dirac Equation from Principles of information
hin con rom eti he
be
p l es ar ch ic s f theor all t
n o
nc i ese cha ion d d
- s,
pri VA al r me rmat it an te m t h e
ep E gin m s y s tr u c t
processing, Phys. Rev. A 90 062106 (2014)
d e EN o d al
t he OF G r t ori antu e inf d rea y si c c o n s b ot to
m
a qu mp oul l p h e
r t he m
on Y ,p fic an
ok build of si n sh
g
o ok RSIT o p eci we c from uantu Usin , the
b VE xtb ‘re ce atio
s
ry I of h o w u l e s t h e q l e s . t i o n s i v e
d ina , UN i c s te or t to quen form t h
ry
eo ows um r ts of rincip eriva spec
t
r n ff se in t
t a k sh an p e c s t p t d p e r o r
ao SIN cha ous e l con tum jus boo e qu e as m fir ficien new tion f er
extr S GI e t r y.
FROM FIRST PRINCIPLES
QUANTUM THEORY
m i a n o
hi s t h iti v f ro f l l y ma pu t
“An COL A m dac logic qua sn g
It i it y. T ildin rintu col s more dica infor com e th
e eo
NI ntu au n c s.
ua ting, s the lear bu te ra th
il to ,
q h ysi licab y re coun pro r and g a ntum ysic s g of
A. Bisio, G. M. D'Ariano, P. Perinotti, Quantum Cellular Automaton Theory of Light,
r t a ta t o IT p p b n
al l ap les, r the atio hor t f fer qu in ph and e in a in
“Pa ascin ting i hing N, M tic
ore er s
a cip te form ith s se. O y and nts erst
a f sen s wis NSO as
the univ al prin to m m in nd w al ea heor stude r und m e
M
nt u of t h
pre dent ARO l of h c u a n t , e ua
o u k w i t o r e t i h o w u a nt o n s , p t i o t u m n a l s d e e p s Q l ow y
Stu OT T A
s he a F el d em
U
t he wor -the earn uc t q uati exce quan ssio g a a c a
Ann. Phys. 368 177 (2016)
is e on ll tr eq th f fe in te is c
SC or y fram mati r wil cons sent d wi rse o , pro seek he He the A nd
T
t he w r e e e u s r re IT. e f a
e fo ad r re at c o er e w h p Q U er tion
o
tum er a n ix in he re iently o rep simil ient arch utsid it y, grou emb nica Xi ).
an
N
s t e o
Qu rath rom tep, t ef fic tion nd as ef fic t res ious
T
er s m u FQ of
t
b u o r y f b y s o w t o l n o t a o d a s a n ed a e c u r n i v s t h e c a , a o mm u t e ( c e c al
Y
U
a ead eri ic C stit ien et i
A
S c eor p
S
o
the Step nd h hica erst ontain s aim as th av i l
. a p d i t P , and of Am hoton ns In puter or Th rou
QUHEOR FIRLESach
p
u r ld , a n c k l l r a o G
gr e u o o k o o we y
s s o e o r iet o r
y P s ti m u te f o n
wo itive an b he b The b y, as e Co
u t of e T h l S o c nt e r f a l Q u of I n s t i t o q u i a s
int or y c eld, tes. soph Pr m a Ce n nt l n ns
s a nt u t i c tio me te r C o l s t i o t i o
the the fi adua philo O i Qua e Op f the unda ar t rime onal Que plica
A. Bisio, G. M. D'Ariano, P. Perinotti, Special relativity in a discrete quantum
r A N f t h o e p e i l p
on derg and R I n s o d o f e r e, e F o e D f P n at
o o na f or a
’A o t h tt h r at i
un e n c e O D a t i y a n L e t d of t w
r a ello e In und riz
te e
ch
es
sci UR und iet e e n s s o g F f th Fo y l P te a s
T ROM CIPl Appro
M A d F o S o c e nz IL , a ofe sitin tee o f the n We he t i o n
9781107043428: D’Ariano, Chiribella and Perinotti: PPC: C M Y K
M O a n c al S c i r n Pr re a
C O n i c s h y s i o of e s t e a t e a V i mi t b e r o m a n he ound .
universe, Phys. Rev. A 94, 04a2120 (2016)
I A c i i s m r w f y
G c h a n P a r d t hw o em H e ty
s s o He g C
r
a
M e e r i c L o mb t N o r r s i ed o n t h e o t h e
s A ong. ndin d a m d the i ve f
Am tuto ing a Ai n e Un cus field and o ed
L L n g K St a s , a a r d . v ia s f o m , d
i
I s t mp u t IB E f H o f t h e y s i c s aw t i o n P a v i t y i a nt u Q X i ) a w a r n s .
F RINmationa
I R o o h a a t i F
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walk in 3 + 1 dimensions, Phil. Trans. R. Soc. A 375: 20160394 (2017) He ernat hof f-
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ISBN 978-1-107-04342-8 GI OLO
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G. M. D’Ariano, M. Erba, P. Perinotti, A. Tosini, Virtually Abelian Quantum Walks, J. Phys. 9 781 1 07 043428 >
A: Math. Theor. 50 035301 (2017)
A. Bisio, G. M. D’Ariano, P. Perinotti, A. Tosini, The Thirring quantum cellular automaton, Phys.
Rev. A 97, 032132 (2018)
Paolo Perinotti Alessandro Bisio Alessandro Tosini Nicola Mosco Marco ErbaGrazie per la vostra attenzione!
Follow project on Researchgate: The algorithmic paradigm:
deriving the whole physics from information-theoretical principles.
REVIEW
G. M. D’Ariano, Physics without Physics, Int. J. Theor. Phys. 128 56 (2017),
[in memoriam of D. Finkelstein]You can also read
