Tensor products of Hilbert spaces and Hilbert-Schmidt operators

Clash Royale CLAN TAG#URR8PPP
up vote
2
down vote
favorite
I am trying to get a better understanding of tensor products of Hilbert spaces. Suppose that $x,yinmathbb H$, where $mathbb H$ is a Hilbert space. As far as I understand, we can think about the tensor $xotimes y$ as a bounded linear operator from $mathbb H$ to $mathbb H$ defined by
$$
(xotimes y)(z)=langle z,yrangle x
$$
for each $xinmathbb H$ and the tensor product $mathbb Hotimes mathbb H$ as the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ (see here). Let us denote the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ by $HS(mathbb H)$.
It seems that we can think about $xotimes y$ as an element in a Hilbert space $HS(mathbb H)$ and we can consider a tensor $xotimes ytildeotimes zotimes w$ with $x,y,z,winmathbb H$ as an element in the tensor product $HS(mathbb H)tildeotimes HS(mathbb H)$.
Does it make sense to define the tensor $xotimes ytildeotimes zotimes w$ by setting
$$
(xotimes ytildeotimes zotimes w)(varphi)=langlevarphi,zotimes wrangle_mathrmHS(xotimes y)
$$
for each $varphiin HS(mathbb H)$, where $langlecdot,cdotrangle$ is a Hilbert-Schmidt inner product? This would mean that we can think about $mathbb Hotimes mathbb Htildeotimes mathbb Hotimes mathbb H$ as the space $HS(HS(mathbb H))$ and, if $varphi=uotimes v$ for some $u,v
inmathbb H$, we would have
$$
(xotimes ytildeotimes zotimes w)(uotimes v)
=langle uotimes v,zotimes wrangle_mathrmHS (xotimes y)
=langle u,zranglelangle w,vrangle(xotimes y).
$$
References (textbooks, papers, etc.) are very welcome. Any help is much appreciated!
functional-analysis reference-request operator-theory hilbert-spaces tensor-products
add a comment |Â
up vote
2
down vote
favorite
I am trying to get a better understanding of tensor products of Hilbert spaces. Suppose that $x,yinmathbb H$, where $mathbb H$ is a Hilbert space. As far as I understand, we can think about the tensor $xotimes y$ as a bounded linear operator from $mathbb H$ to $mathbb H$ defined by
$$
(xotimes y)(z)=langle z,yrangle x
$$
for each $xinmathbb H$ and the tensor product $mathbb Hotimes mathbb H$ as the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ (see here). Let us denote the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ by $HS(mathbb H)$.
It seems that we can think about $xotimes y$ as an element in a Hilbert space $HS(mathbb H)$ and we can consider a tensor $xotimes ytildeotimes zotimes w$ with $x,y,z,winmathbb H$ as an element in the tensor product $HS(mathbb H)tildeotimes HS(mathbb H)$.
Does it make sense to define the tensor $xotimes ytildeotimes zotimes w$ by setting
$$
(xotimes ytildeotimes zotimes w)(varphi)=langlevarphi,zotimes wrangle_mathrmHS(xotimes y)
$$
for each $varphiin HS(mathbb H)$, where $langlecdot,cdotrangle$ is a Hilbert-Schmidt inner product? This would mean that we can think about $mathbb Hotimes mathbb Htildeotimes mathbb Hotimes mathbb H$ as the space $HS(HS(mathbb H))$ and, if $varphi=uotimes v$ for some $u,v
inmathbb H$, we would have
$$
(xotimes ytildeotimes zotimes w)(uotimes v)
=langle uotimes v,zotimes wrangle_mathrmHS (xotimes y)
=langle u,zranglelangle w,vrangle(xotimes y).
$$
References (textbooks, papers, etc.) are very welcome. Any help is much appreciated!
functional-analysis reference-request operator-theory hilbert-spaces tensor-products
I've never read a construction like this about tensor products between Hilbert Spaces, nonetheless, if your first characterization of tensor products is fine, there wouldn't be any reason to think that your characterizaction about tensor product between tensor products would be bad. Also, if you found some references about this I would appreciate if you could comment about them.
â Esteban Gutiérrez
May 16 at 3:08
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I am trying to get a better understanding of tensor products of Hilbert spaces. Suppose that $x,yinmathbb H$, where $mathbb H$ is a Hilbert space. As far as I understand, we can think about the tensor $xotimes y$ as a bounded linear operator from $mathbb H$ to $mathbb H$ defined by
$$
(xotimes y)(z)=langle z,yrangle x
$$
for each $xinmathbb H$ and the tensor product $mathbb Hotimes mathbb H$ as the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ (see here). Let us denote the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ by $HS(mathbb H)$.
It seems that we can think about $xotimes y$ as an element in a Hilbert space $HS(mathbb H)$ and we can consider a tensor $xotimes ytildeotimes zotimes w$ with $x,y,z,winmathbb H$ as an element in the tensor product $HS(mathbb H)tildeotimes HS(mathbb H)$.
Does it make sense to define the tensor $xotimes ytildeotimes zotimes w$ by setting
$$
(xotimes ytildeotimes zotimes w)(varphi)=langlevarphi,zotimes wrangle_mathrmHS(xotimes y)
$$
for each $varphiin HS(mathbb H)$, where $langlecdot,cdotrangle$ is a Hilbert-Schmidt inner product? This would mean that we can think about $mathbb Hotimes mathbb Htildeotimes mathbb Hotimes mathbb H$ as the space $HS(HS(mathbb H))$ and, if $varphi=uotimes v$ for some $u,v
inmathbb H$, we would have
$$
(xotimes ytildeotimes zotimes w)(uotimes v)
=langle uotimes v,zotimes wrangle_mathrmHS (xotimes y)
=langle u,zranglelangle w,vrangle(xotimes y).
$$
References (textbooks, papers, etc.) are very welcome. Any help is much appreciated!
functional-analysis reference-request operator-theory hilbert-spaces tensor-products
I am trying to get a better understanding of tensor products of Hilbert spaces. Suppose that $x,yinmathbb H$, where $mathbb H$ is a Hilbert space. As far as I understand, we can think about the tensor $xotimes y$ as a bounded linear operator from $mathbb H$ to $mathbb H$ defined by
$$
(xotimes y)(z)=langle z,yrangle x
$$
for each $xinmathbb H$ and the tensor product $mathbb Hotimes mathbb H$ as the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ (see here). Let us denote the space of Hilbert-Schmidt operators from $mathbb H$ to $mathbb H$ by $HS(mathbb H)$.
It seems that we can think about $xotimes y$ as an element in a Hilbert space $HS(mathbb H)$ and we can consider a tensor $xotimes ytildeotimes zotimes w$ with $x,y,z,winmathbb H$ as an element in the tensor product $HS(mathbb H)tildeotimes HS(mathbb H)$.
Does it make sense to define the tensor $xotimes ytildeotimes zotimes w$ by setting
$$
(xotimes ytildeotimes zotimes w)(varphi)=langlevarphi,zotimes wrangle_mathrmHS(xotimes y)
$$
for each $varphiin HS(mathbb H)$, where $langlecdot,cdotrangle$ is a Hilbert-Schmidt inner product? This would mean that we can think about $mathbb Hotimes mathbb Htildeotimes mathbb Hotimes mathbb H$ as the space $HS(HS(mathbb H))$ and, if $varphi=uotimes v$ for some $u,v
inmathbb H$, we would have
$$
(xotimes ytildeotimes zotimes w)(uotimes v)
=langle uotimes v,zotimes wrangle_mathrmHS (xotimes y)
=langle u,zranglelangle w,vrangle(xotimes y).
$$
References (textbooks, papers, etc.) are very welcome. Any help is much appreciated!
functional-analysis reference-request operator-theory hilbert-spaces tensor-products
edited Mar 6 at 17:32
asked Mar 5 at 10:39
Cm7F7Bb
12.1k32142
12.1k32142
I've never read a construction like this about tensor products between Hilbert Spaces, nonetheless, if your first characterization of tensor products is fine, there wouldn't be any reason to think that your characterizaction about tensor product between tensor products would be bad. Also, if you found some references about this I would appreciate if you could comment about them.
â Esteban Gutiérrez
May 16 at 3:08
add a comment |Â
I've never read a construction like this about tensor products between Hilbert Spaces, nonetheless, if your first characterization of tensor products is fine, there wouldn't be any reason to think that your characterizaction about tensor product between tensor products would be bad. Also, if you found some references about this I would appreciate if you could comment about them.
â Esteban Gutiérrez
May 16 at 3:08
I've never read a construction like this about tensor products between Hilbert Spaces, nonetheless, if your first characterization of tensor products is fine, there wouldn't be any reason to think that your characterizaction about tensor product between tensor products would be bad. Also, if you found some references about this I would appreciate if you could comment about them.
â Esteban Gutiérrez
May 16 at 3:08
I've never read a construction like this about tensor products between Hilbert Spaces, nonetheless, if your first characterization of tensor products is fine, there wouldn't be any reason to think that your characterizaction about tensor product between tensor products would be bad. Also, if you found some references about this I would appreciate if you could comment about them.
â Esteban Gutiérrez
May 16 at 3:08
add a comment |Â
active
oldest
votes
active
oldest
votes
active
oldest
votes
active
oldest
votes
active
oldest
votes
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2677590%2ftensor-products-of-hilbert-spaces-and-hilbert-schmidt-operators%23new-answer', 'question_page');
);
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
I've never read a construction like this about tensor products between Hilbert Spaces, nonetheless, if your first characterization of tensor products is fine, there wouldn't be any reason to think that your characterizaction about tensor product between tensor products would be bad. Also, if you found some references about this I would appreciate if you could comment about them.
â Esteban Gutiérrez
May 16 at 3:08