
Memristor – The fictional circuit element - godelmachine
https://arxiv.org/abs/1808.05982
======
appleflaxen
I went down the rabbit hole.

Best terminal branches I found are:

* HP created something they claimed was a memristor [1]

* there were thermodynamic arguments about why it wouldn't work [2]

* HP discontinued the architecture based on the component [3]

1\. [https://arstechnica.com/information-technology/2014/06/hp-
la...](https://arstechnica.com/information-technology/2014/06/hp-labs-machine-
dissolves-the-difference-between-disk-and-memory/)

2\.
[https://arxiv.org/ftp/arxiv/papers/1207/1207.7319.pdf](https://arxiv.org/ftp/arxiv/papers/1207/1207.7319.pdf)

3\.
[https://www.theregister.co.uk/2016/11/29/hp_labs_delivered_m...](https://www.theregister.co.uk/2016/11/29/hp_labs_delivered_machine_proof_of_concept_prototype_but_machine_product_is_no_more)

~~~
no_identd
Well...

One thing about the OP paper smells very fishy to me:

About two years ago, an extremely important result about Memristors and the
notion of circuit elements in general came out. Unfortunately, it didn't get a
lot of attention, and remains not-that-well-known even among experts. But:
Anyone making claims like the OP paper would HAVE TO consider it in their
model if they want to get taken serious. Here's the paper:

[https://hal.archives-ouvertes.fr/hal-01322396/document](https://hal.archives-
ouvertes.fr/hal-01322396/document) Abdelouahab, Mohammed-Salah; Lozi, René;
Chua, Leon O. - Memfractance: A Mathematical Paradigm for Circuit Elements
with Memory [2016]

The fact that the OP paper doesn't even mention Memfractance makes me highly
suspicious, and doubly so as the OP paper also brings up a "periodic table" of
circuit elements - something the Memfractance paper also does (embedded in
ℝ²), but uh... let's say with a lot more behind it. In fact, I'll quote the
entire "Conclusions" section of the Memfractance paper here:

>In this paper, we have used fractional calculus in order to generalize and
provide a mathematical frame for circuit elements with memory: memfractance.
We have emphasized that the memfractance is a general paradigm for unifying
and enlarging the family of memristive, memcapacitive and memin ductive
elements. The motivation and significance of this paper is that there may
exist future nano-electronics devices that are more realistically modeled with
memfractance elements

>We have generalized the definition of fractance which was first introduced in
1983, and after that, introduced the paradigm of memfractance which is fitted
for circuit elements with memory such as memristor, meminductor, memcapacitor
and second-order memristor first introduced here. We have defined a new
element called memfractor which possesses interpolated characteristics between
those four circuit elements.

>We have then generalized Ohm’s law to memfractor and proved it. A particular,
albeit wide-ranging, case of memfractance: the interpolated memfractance has
been carefully studied through several numerical illustrative examples.
Special attention has been devoted to the interpolated char- acteristic of a
memfractor lying between memristor and memcapacitor which exhibits an
unexpected new behavior of time variation of flux (φ–t curve). This phenomenon
has been studied very carefully by the means of rigorous proofs.

>Finally, following Chua’s recent work in which an infinite discrete family of
circuit elements: the (α,β) element is introduced in the scope of developing a
rigorous mathematical theory of nonlinear circuits, we extend the previous
generalized Ohm’s law in order to embed memfractors elements into this
periodic table. For this aim, we define an infinite continued family of
circuit elements including circuit elements with memory (such as second-order
memcapacitor and meminductor and third-order memristor), with a special
metric. We call this family: fractional circuit element family.

Note: That last passage is a reference to this specific paper:

[https://www.semanticscholar.org/paper/The-Fourth-Element-
Chu...](https://www.semanticscholar.org/paper/The-Fourth-Element-
Chua/2d194f8216afbd5c9999b0931b9b75d47f923c51) \- Chua, Leon O. - The Fourth
Element [2012]

Which the OP paper also doesn't cite.

To me, this looks like a FUD campaign by Intel.

I also briefly glanced over the OP paper besides checking for citations in it,
and found this passage:

"We have borrowed the expression “periodic table” as attributed to Chua" \-
which cites a secondary resource from 2008, before Chua's two above papers.
Looking for any words starting with, or containing a fragment of, "fract" in
the paper also yields no results.

Looks like the typical outcome of someone who thinks they don't suck at
literature research, but does suck at literature research, which, quite
honestly, the vast majority of scientists do. Ask a randomly sampled
researcher if they ever heard the term "Main path analysis" and they'll stare
at you like a deer staring into headlights.

Having said that:

The paper does seem to bring up a few valid points, e.g. people making errors
& drawing bad conclusions from mislabeled diagrams. This isn't an issue in
Chua's work, however.

Oh, and: Here, some slides on memfractance:

[http://slideplayer.com/slide/3869533/](http://slideplayer.com/slide/3869533/)

Edit:

Actually, this got generalized even further in early 2017:

[https://www.sciencedirect.com/science/article/pii/S100757041...](https://www.sciencedirect.com/science/article/pii/S1007570416301988)
Machado, J.Tenreiro; Galhano, Alexandra M. - Generalized two-port elements

~~~
phkahler
>>In this paper, we have used fractional calculus in order to generalize and
provide a mathematical frame for circuit elements with memory: memfractance.
We have emphasized that the memfractance is a general paradigm for unifying
and enlarging the family of memristive, memcapacitive and memin ductive
elements. The motivation and significance of this paper is that there may
exist future nano-electronics devices that are more realistically modeled with
memfractance elements

That sounds like a hoax to me. I had to look up fractional calculus, but it
appears to be a real thing. It still sounds ridiculous and appears to bring in
memcapitive and meminductive elements to their odd new world. At the end of
the day, writing papers with strange terms isn't nearly as useful (to the rest
of us) as actually producing a new device.

~~~
beautifulfreak
Here's a well-explained article about fractional derivatives and integrals
(1). One freaky outcome is that the factorials of fractional numbers can be
found. (Example: negative one half factorial = square root of pi.) It can be
applied to all things quantum mechanical (2) so there's a fractional
Schrödinger equation etc. I had to look it up, but the links are worth the
bother.

(1)
[https://www.mathpages.com/home/kmath616/kmath616.htm](https://www.mathpages.com/home/kmath616/kmath616.htm)
(2) [https://arxiv.org/abs/1009.5533](https://arxiv.org/abs/1009.5533)

[https://www.mathpages.com/home/kmath616/kmath616.htm](https://www.mathpages.com/home/kmath616/kmath616.htm)

------
bacon_waffle
Pragmatic engineer's version: digikey shows 0 search results for "memristor".

(funny enough, doing the same at aliexpress yields a young kid's plastic ball
ad, containing "Warning:Memristor")

~~~
taneq
> (funny enough, doing the same at aliexpress yields a young kid's plastic
> ball ad, containing "Warning:Memristor")

Happy Fun Ball may contain one or more memristors, and may or may not be
sentient as a result. It is recommended to treat Happy Fun Ball with respect
as a precaution.

~~~
mchannon
For those among us 30 and younger who are too young to get the joke,

[https://en.wikipedia.org/wiki/Happy_Fun_Ball](https://en.wikipedia.org/wiki/Happy_Fun_Ball)

------
DonHopkins
My favorite fictional-sounding-but-real storage device is the Stringy Floppy!

When I hung out at Radio Shack after school to play with the TRS-80's, some
guy came by and showed his off, and I was in awe, and so jealous at how fast
it was! I was sure that Stringy Floppies were the wave of the future. You
didn't need to rewind them like tapes, because they wound back around!!!

[https://en.wikipedia.org/wiki/Exatron_Stringy_Floppy](https://en.wikipedia.org/wiki/Exatron_Stringy_Floppy)

[https://www.youtube.com/watch?v=EBfNy021K2Q](https://www.youtube.com/watch?v=EBfNy021K2Q)

Then there was the Transputer!

[https://en.wikipedia.org/wiki/Transputer](https://en.wikipedia.org/wiki/Transputer)

~~~
aidenn0
The Transputer is a success; a lot of the ideas developed for it are
mainstream today, even if we don't call it a transputer.

Kind of like all of the ideas from AI in the 70s and 80s that worked we don't
call AI anymore.

------
mchannon
Fictional or no, this company sells them:

[https://knowm.org/memristors/](https://knowm.org/memristors/)

~~~
mfer
You can buy them. Sometimes under branding that doesn't say memrister.

You can learn how they work and the science (see the video on
[https://knowm.org/memristors/](https://knowm.org/memristors/))

Are they a fundamental circuit element or one of the existing fundamental
elements? We can let scientists debate that.

~~~
VikingCoder
Yeah, I'm really lost.

I feel like someone described useful properties of A Thing if it existed.

Then we figured out how to make A Thing that had those useful properties.

Is it A Thing, or Two Things?

That's pedantic. Pragmatically, don't we have the useful properties?

~~~
YeGoblynQueenne
Well, in that case was the Mechanical Turk a machine that played chess? I
mean, it _was_ a machine and it _did_ play chess. There was a person inside it
that actually did all the work, but does that make it not a machine that
played chess? We could debate the meaning of "plays" until the cows come home
and perhaps arguing that the machine should be able to play chess on its own,
or that it doesn't because one component of it is a human being that also
functions independently to the machine is pedantic. But perhaps it is
productive after all, to challenge and analyse claims regarding the nature of
things people make.

If I understand this memristor paper correctly, the whole issue seems to be
that what is supposed to be a new kind of Thing, that didn't exist before, is
actually made up of already existing Things with well-understood properties in
one possible configuration that doesn't do anything radically new, that other
configurations can't already do anyway.

So in other ways- we have the useful properties but a) we always had them and
b) there's no new Thing.

~~~
VikingCoder
We did not always have what HP created.

It's not a trick, it just doesn't work on the underlying mechanism we thought
it did. The new configuration is itself radically new.

The Mechanical Turk was a trick, designed to deceive.

It's a very unfair comparison.

------
leni536
> _A nonlinear ϕ-q curve will always have a positive, albeit variable slope.
> However, the ratio of ϕ to q still has the units of ohm, without a phase
> shift, making this a nonlinear resistor._

I think this is false. A nonlinear ϕ-q curve will yield a resistance which
depends on time in a manner that can't be described by a single nonlinear v-i
curve.

------
jamesough
Heard on grape vine that IBM claim to have pulled first silicon for a
memristor RPU (design like below) just over a month ago.

[https://www.nature.com/articles/s41586-018-0180-5](https://www.nature.com/articles/s41586-018-0180-5)

------
devnull791101
i seem to remember HP having made these a number of years ago

~~~
cmiles74
This article from Ars Technica talks a little bit about memristors and HP's
plans for "The Machine". The original plan was for The Machine to demonstrate
this technology, but HP ended up removing feature after feature (including
memristor technology) before it's release. They quote John Sontag from HP in
the article:

"The simplest way to think about it is this—take a DRAM DIMM out, and put a
memristor DIMM in,” said Sontag. “You now have another pool of memory that’s
denser and nonvolatile. It’s a new class of memory—the consequence for
operating systems is that moving stuff around from I/O devices [to and from
disk] becomes unnecessary."

[https://arstechnica.com/information-technology/2014/06/hp-
la...](https://arstechnica.com/information-technology/2014/06/hp-labs-machine-
dissolves-the-difference-between-disk-and-memory/)

~~~
eat_veggies
Doesn't magnetic core memory (which has been around forever) do similar
things?

~~~
pjc50
The density is _terrible_ and the read process is destructive.

~~~
marcosdumay
Both seem to apply equally well for memristors. In both theory and practice.

------
usernam33
I dream of a bright Future where my PC will have no ram, hdd or ssd but only
memristor memory. No need for booting or shutdown, I just add power and
everything will be the same as it was when last used.

Since I first read about them years ago this is still what I am waiting for
even if it does not seem to be at grasp.

~~~
SamReidHughes
You've got to be able to reboot for when program bugs leave your memory in an
invalid state.

~~~
Koshkin
Rebooting does not help when your _files_ are in an invalid state. (This may
be relevant to software environments which persist the state of the entire
"world.")

------
hatsunearu
tldr + spoilers:

there doesn't seem to be a mechanism for memristors to exist without
significant nonlinearity or being a fully passive device, so it's kind of hard
to say it's a fundamental circuit element

------
grillvogel
more like memeristor

------
contravariant
I disagree with their claim that current is the time derivative of charge.

~~~
InitialLastName
Are you being as pedantic as to ask for "through an area"? Because that's
literally the defined relationship between current and charge.

~~~
contravariant
This isn't mere pedantry, there is a difference between current and the time
derivative of charge, I don't mind that they prefer to use one or the other,
but if you insist on making a periodic table then you've got to take both into
account.

It's also an especially bad idea to claim the time derivative of current is
the the double derivative of charge, given that these are two very different
notions of derivative.

To clarify, claiming current is the derivative of charge is like claiming the
current of a river is the derivative of it's water level.

~~~
lnx01
Current is unequivocally the time derivative of charge. There're no two ways
about it.

i(t) = dQ(t) / dt

"To clarify, claiming current is the derivative of charge is like claiming the
current of a river is the derivative of it's water level." This statement is
wrong, while water in some cases provides a decent analogy for electricity,
this is not one of them.

~~~
contravariant
If I have a piece of wire with a constant current through it the charge
everywhere on the wire remains constant. In fact the charge will be more or
less neutral in most cases.

Note that the alternative would be that the wire somehow accumulates charge as
it passes current, which clearly isn't happening.

~~~
tremon
No, you are wrong. Electrical current is the mathematical representation of a
charged particle moving between two points. The value of the current is
directly related to the amount of charge being moved.

As for your "wire" example, you're conveniently ignoring that a single (open-
ended) wire isn't a closed circuit and as such there can be no current (and
hence no accumulating charge). And if it's a closed circuit, then there are
other elements in the circuit that consume or generate charge.

~~~
contravariant
Fine, charge a circular piece of wire, place it in space and spin it around.
Voila, current without any accumulation of charge.

Honestly I'm confused why it's turning out to be such a controversial point
that there's a difference between a change in charge and the movement of
charges.

Heck in their diagram they claim that the voltage across an inductor is the
double derivative of its charge, but inductors can't even hold charge so it's
unclear what they're trying to say. They also claim that the charge across a
resistor is somehow related to the integral of the voltage across it, but
again (ideal) resistors can't really hold charge. The only way to interpret
this supposedly 'universal' periodic system is by interpreting charge and its
derivatives in different ways depending on context, which isn't convincing in
a supposedly universal system.

~~~
drostie
It's ok, if I didn't have a Master's in the field I would probably have
similarly down voted you.

The problem is mainly that the criticism you are making is not great for
pedagogy. What is being called “charge” is probably something like
“disposition to accumulate charge” or so, in the same way that force is not
actually mass times acceleration, but it's mass times a disposition to
accelerate, so that you can do things like measure my weight-force even though
I’m not falling through the floor.

The dispositional truth of the matter is fundamentally more cognitively
complex to teach than the simple rule that you get when you say that
everything does what it's disposed to do, and so everybody has memorized the
version of the definitions that has no dispositions, and gets very confused
when you point out that aspect of those definitions.

~~~
contravariant
I suppose I also didn't provide an awful lot of explanation to my point, but I
figured I could just explain when asked. I didn't expect the difference
between current and a change in charge to be this controversial.

~~~
Koshkin
Except there has been no controversy at all. Everybody understands that
current (i. e. _flow_ of electric charge, water, etc.) may have nothing
whatsoever to do with "change in charge" (or in the mass of water) contained
in a volume of space through which charge or water flows.

